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Overview
Comment:Change 'stack' to the more descriptive 'no-push' in vdbe.c. (CVS 2429)
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Files: files | file ages | folders
SHA1:7e54d3c7289c091d449844d21b923e553f1d1f5f
User & Date: danielk1977 2005-03-29 13:07:00
Context
2005-03-29
13:17
Fix a C++-ism in the code. (CVS 2430) check-in: 312587ac user: drh tags: trunk
13:07
Change 'stack' to the more descriptive 'no-push' in vdbe.c. (CVS 2429) check-in: 7e54d3c7 user: danielk1977 tags: trunk
08:26
Reduce the space allocated for the runtime virtual machine stack. (CVS 2428) check-in: 7d6818da user: danielk1977 tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to mkopcodeh.awk.

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    if($i=="same" && $(i+1)=="as"){
      sym = $(i+2)
      sub(/,/,"",sym)
      op[name] = tk[sym]
      used[op[name]] = 1
      sameas[op[name]] = sym
    }
    if($i=="stack"){
      stack[name] = 1
    }
  }
}

# Assign numbers to all opcodes and output the result.
END {
  cnt = 0
................................................................................
      printf "#define %-25s %15d\n", sprintf( "OP_NotUsed_%-3d", i ), i
    }
  }

  # Generate the 10 16-bit bitmasks used by function opcodeUsesStack()
  # in vdbeaux.c. See comments in that function for details.
  # 
  stack[0] = 0              # 0..15
  stack[1] = 0              # 16..31
  stack[2] = 0              # 32..47
  stack[3] = 0              # 48..63
  stack[4] = 0              # 64..79
  stack[5] = 0              # 80..95
  stack[6] = 0              # 96..111
  stack[7] = 0              # 112..127
  stack[8] = 0              # 128..143
  stack[9] = 0              # 144..159
  for(name in op){
    if( stack[name] ){
      n = op[name]
      j = n%16
      i = ((n - j)/16)
      stack[i] = stack[i] + (2^j)
    }
  }
  printf "\n"
  for(i=0; i<10; i++){
    printf "#define STACK_MASK_%d %d\n", i, stack[i]
  }

}







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    if($i=="same" && $(i+1)=="as"){
      sym = $(i+2)
      sub(/,/,"",sym)
      op[name] = tk[sym]
      used[op[name]] = 1
      sameas[op[name]] = sym
    }
    if($i=="no-push"){
      nopush[name] = 1
    }
  }
}

# Assign numbers to all opcodes and output the result.
END {
  cnt = 0
................................................................................
      printf "#define %-25s %15d\n", sprintf( "OP_NotUsed_%-3d", i ), i
    }
  }

  # Generate the 10 16-bit bitmasks used by function opcodeUsesStack()
  # in vdbeaux.c. See comments in that function for details.
  # 
  nopush[0] = 0              # 0..15
  nopush[1] = 0              # 16..31
  nopush[2] = 0              # 32..47
  nopush[3] = 0              # 48..63
  nopush[4] = 0              # 64..79
  nopush[5] = 0              # 80..95
  nopush[6] = 0              # 96..111
  nopush[7] = 0              # 112..127
  nopush[8] = 0              # 128..143
  nopush[9] = 0              # 144..159
  for(name in op){
    if( nopush[name] ){
      n = op[name]
      j = n%16
      i = ((n - j)/16)
      nopush[i] = nopush[i] + (2^j)
    }
  }
  printf "\n"
  for(i=0; i<10; i++){
    printf "#define NOPUSH_MASK_%d %d\n", i, nopush[i]
  }
}

Changes to src/vdbe.c.

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**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.462 2005/03/29 08:26:13 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
      }
      nProgressOps++;
    }
#endif

#ifndef NDEBUG
    /* This is to check that the return value of static function
    ** opcodeUsesStack() (see vdbeaux.c) returns values that match the
    ** implementation of the virtual machine in this file. If
    ** opcodeUsesStack() returns non-zero, then the stack is guarenteed
    ** not to grow when the opcode is executed. If it returns zero, then
    ** the stack may grow by at most 1.
    **
    ** The global wrapper function sqlite3VdbeOpcodeUsesStack() is not 
    ** available if NDEBUG is defined at build time.
    */ 
    pStackLimit = pTos;
    if( !sqlite3VdbeOpcodeUsesStack(pOp->opcode) ){
      pStackLimit++;
    }
#endif

    switch( pOp->opcode ){

/*****************************************************************************
................................................................................
** will be filled with #defines that give unique integer values to each
** opcode and the opcodes.c file is filled with an array of strings where
** each string is the symbolic name for the corresponding opcode.  If the
** case statement is followed by a comment of the form "/# same as ... #/"
** that comment is used to determine the particular value of the opcode.
**
** If a comment on the same line as the "case OP_" construction contains
** the word "stack", then the opcode is guarenteed not to grow the 
** vdbe stack when it is executed. See function opcodeUsesStack() in
** vdbeaux.c for details.
**
** Documentation about VDBE opcodes is generated by scanning this file
** for lines of that contain "Opcode:".  That line and all subsequent
** comment lines are used in the generation of the opcode.html documentation
** file.
**
................................................................................
/* Opcode:  Goto * P2 *
**
** An unconditional jump to address P2.
** The next instruction executed will be 
** the one at index P2 from the beginning of
** the program.
*/
case OP_Goto: {             /* no stack growth */
  CHECK_FOR_INTERRUPT;
  pc = pOp->p2 - 1;
  break;
}

/* Opcode:  Gosub * P2 *
**
................................................................................
** and then jump to address P2.
**
** The return address stack is of limited depth.  If too many
** OP_Gosub operations occur without intervening OP_Returns, then
** the return address stack will fill up and processing will abort
** with a fatal error.
*/
case OP_Gosub: {            /* no stack growth */
  assert( p->returnDepth<sizeof(p->returnStack)/sizeof(p->returnStack[0]) );
  p->returnStack[p->returnDepth++] = pc+1;
  pc = pOp->p2 - 1;
  break;
}

/* Opcode:  Return * * *
**
** Jump immediately to the next instruction after the last unreturned
** OP_Gosub.  If an OP_Return has occurred for all OP_Gosubs, then
** processing aborts with a fatal error.
*/
case OP_Return: {           /* no stack growth */
  assert( p->returnDepth>0 );
  p->returnDepth--;
  pc = p->returnStack[p->returnDepth] - 1;
  break;
}

/* Opcode:  Halt P1 P2 *
................................................................................
** then back out all changes that have occurred during this execution of the
** VDBE, but do not rollback the transaction. 
**
** There is an implied "Halt 0 0 0" instruction inserted at the very end of
** every program.  So a jump past the last instruction of the program
** is the same as executing Halt.
*/
case OP_Halt: {            /* no stack growth */
  p->pTos = pTos;
  p->rc = pOp->p1;
  p->pc = pc;
  p->errorAction = pOp->p2;
  if( pOp->p3 ){
    sqlite3SetString(&p->zErrMsg, pOp->p3, (char*)0);
  }
................................................................................
  break;
}

/* Opcode: Pop P1 * *
**
** P1 elements are popped off of the top of stack and discarded.
*/
case OP_Pop: {            /* no stack growth */
  assert( pOp->p1>=0 );
  popStack(&pTos, pOp->p1);
  assert( pTos>=&p->aStack[-1] );
  break;
}

/* Opcode: Dup P1 P2 *
................................................................................
** the stack and pushed back on top of the stack.  The
** top of the stack is element 0, so "Pull 0 0 0" is
** a no-op.  "Pull 1 0 0" swaps the top two elements of
** the stack.
**
** See also the Dup instruction.
*/
case OP_Pull: {            /* no stack growth */
  Mem *pFrom = &pTos[-pOp->p1];
  int i;
  Mem ts;

  ts = *pFrom;
  Deephemeralize(pTos);
  for(i=0; i<pOp->p1; i++, pFrom++){
................................................................................

/* Opcode: Push P1 * *
**
** Overwrite the value of the P1-th element down on the
** stack (P1==0 is the top of the stack) with the value
** of the top of the stack.  Then pop the top of the stack.
*/
case OP_Push: {            /* no stack growth */
  Mem *pTo = &pTos[-pOp->p1];

  assert( pTo>=p->aStack );
  sqlite3VdbeMemMove(pTo, pTos);
  pTos--;
  break;
}
................................................................................

/* Opcode: Callback P1 * *
**
** Pop P1 values off the stack and form them into an array.  Then
** invoke the callback function using the newly formed array as the
** 3rd parameter.
*/
case OP_Callback: {            /* no stack growth */
  int i;
  assert( p->nResColumn==pOp->p1 );

  for(i=0; i<pOp->p1; i++){
    Mem *pVal = &pTos[0-i];
    sqlite3VdbeMemNulTerminate(pVal);
    storeTypeInfo(pVal, db->enc);
................................................................................
** first (what was on top of the stack) from the second (the
** next on stack)
** and push the remainder after division onto the stack.  If either element
** is a string then it is converted to a double using the atof()
** function before the division.  Division by zero returns NULL.
** If either operand is NULL, the result is NULL.
*/
case OP_Add:                   /* same as TK_PLUS, no stack growth */
case OP_Subtract:              /* same as TK_MINUS, no stack growth */
case OP_Multiply:              /* same as TK_STAR, no stack growth */
case OP_Divide:                /* same as TK_SLASH, no stack growth */
case OP_Remainder: {           /* same as TK_REM, no stack growth */
  Mem *pNos = &pTos[-1];
  assert( pNos>=p->aStack );
  if( ((pTos->flags | pNos->flags) & MEM_Null)!=0 ){
    Release(pTos);
    pTos--;
    Release(pTos);
    pTos->flags = MEM_Null;
................................................................................
** be returned. This is used by the built-in min(), max() and nullif()
** functions.
**
** The interface used by the implementation of the aforementioned functions
** to retrieve the collation sequence set by this opcode is not available
** publicly, only to user functions defined in func.c.
*/
case OP_CollSeq: {             /* no stack growth */
  assert( pOp->p3type==P3_COLLSEQ );
  break;
}

/* Opcode: Function P1 P2 P3
**
** Invoke a user function (P3 is a pointer to a Function structure that
................................................................................
/* Opcode: ShiftRight * * *
**
** Pop the top two elements from the stack.  Convert both elements
** to integers.  Push back onto the stack the second element shifted
** right by N bits where N is the top element on the stack.
** If either operand is NULL, the result is NULL.
*/
case OP_BitAnd:                 /* same as TK_BITAND, no stack growth */
case OP_BitOr:                  /* same as TK_BITOR, no stack growth */
case OP_ShiftLeft:              /* same as TK_LSHIFT, no stack growth */
case OP_ShiftRight: {           /* same as TK_RSHIFT, no stack growth */
  Mem *pNos = &pTos[-1];
  int a, b;

  assert( pNos>=p->aStack );
  if( (pTos->flags | pNos->flags) & MEM_Null ){
    popStack(&pTos, 2);
    pTos++;
................................................................................
/* Opcode: AddImm  P1 * *
** 
** Add the value P1 to whatever is on top of the stack.  The result
** is always an integer.
**
** To force the top of the stack to be an integer, just add 0.
*/
case OP_AddImm: {            /* no stack growth */
  assert( pTos>=p->aStack );
  Integerify(pTos);
  pTos->i += pOp->p1;
  break;
}

/* Opcode: ForceInt P1 P2 *
................................................................................
** the stack is not numeric (meaning that is is a NULL or a string that
** does not look like an integer or floating point number) then pop the
** stack and jump to P2.  If the top of the stack is numeric then
** convert it into the least integer that is greater than or equal to its
** current value if P1==0, or to the least integer that is strictly
** greater than its current value if P1==1.
*/
case OP_ForceInt: {            /* no stack growth */
  int v;
  assert( pTos>=p->aStack );
  applyAffinity(pTos, SQLITE_AFF_INTEGER, db->enc);
  if( (pTos->flags & (MEM_Int|MEM_Real))==0 ){
    Release(pTos);
    pTos--;
    pc = pOp->p2 - 1;
................................................................................
** with out data loss, then jump immediately to P2, or if P2==0
** raise an SQLITE_MISMATCH exception.
**
** If the top of the stack is not an integer and P2 is not zero and
** P1 is 1, then the stack is popped.  In all other cases, the depth
** of the stack is unchanged.
*/
case OP_MustBeInt: {            /* no stack growth */
  assert( pTos>=p->aStack );
  applyAffinity(pTos, SQLITE_AFF_INTEGER, db->enc);
  if( (pTos->flags & MEM_Int)==0 ){
    if( pOp->p2==0 ){
      rc = SQLITE_MISMATCH;
      goto abort_due_to_error;
    }else{
................................................................................
*/
/* Opcode: Ge P1 P2 P3
**
** This works just like the Eq opcode except that the jump is taken if
** the 2nd element down on the stack is greater than or equal to the
** top of the stack.  See the Eq opcode for additional information.
*/
case OP_Eq:               /* same as TK_EQ, no stack growth */
case OP_Ne:               /* same as TK_NE, no stack growth */
case OP_Lt:               /* same as TK_LT, no stack growth */
case OP_Le:               /* same as TK_LE, no stack growth */
case OP_Gt:               /* same as TK_GT, no stack growth */
case OP_Ge: {             /* same as TK_GE, no stack growth */
  Mem *pNos;
  int flags;
  int res;
  char affinity;

  pNos = &pTos[-1];
  flags = pTos->flags|pNos->flags;
................................................................................
*/
/* Opcode: Or * * *
**
** Pop two values off the stack.  Take the logical OR of the
** two values and push the resulting boolean value back onto the
** stack. 
*/
case OP_And:              /* same as TK_AND, no stack growth */
case OP_Or: {             /* same as TK_OR, no stack growth */
  Mem *pNos = &pTos[-1];
  int v1, v2;    /* 0==TRUE, 1==FALSE, 2==UNKNOWN or NULL */

  assert( pNos>=p->aStack );
  if( pTos->flags & MEM_Null ){
    v1 = 2;
  }else{
................................................................................
*/
/* Opcode: AbsValue * * *
**
** Treat the top of the stack as a numeric quantity.  Replace it
** with its absolute value. If the top of the stack is NULL
** its value is unchanged.
*/
case OP_Negative:              /* same as TK_UMINUS, no stack growth */
case OP_AbsValue: {
  assert( pTos>=p->aStack );
  if( pTos->flags & MEM_Real ){
    Release(pTos);
    if( pOp->opcode==OP_Negative || pTos->r<0.0 ){
      pTos->r = -pTos->r;
    }
................................................................................

/* Opcode: Not * * *
**
** Interpret the top of the stack as a boolean value.  Replace it
** with its complement.  If the top of the stack is NULL its value
** is unchanged.
*/
case OP_Not: {                /* same as TK_NOT, no stack growth */
  assert( pTos>=p->aStack );
  if( pTos->flags & MEM_Null ) break;  /* Do nothing to NULLs */
  Integerify(pTos);
  assert( (pTos->flags & MEM_Dyn)==0 );
  pTos->i = !pTos->i;
  pTos->flags = MEM_Int;
  break;
................................................................................

/* Opcode: BitNot * * *
**
** Interpret the top of the stack as an value.  Replace it
** with its ones-complement.  If the top of the stack is NULL its
** value is unchanged.
*/
case OP_BitNot: {             /* same as TK_BITNOT, no stack growth */
  assert( pTos>=p->aStack );
  if( pTos->flags & MEM_Null ) break;  /* Do nothing to NULLs */
  Integerify(pTos);
  assert( (pTos->flags & MEM_Dyn)==0 );
  pTos->i = ~pTos->i;
  pTos->flags = MEM_Int;
  break;
................................................................................
}

/* Opcode: Noop * * *
**
** Do nothing.  This instruction is often useful as a jump
** destination.
*/
case OP_Noop: {            /* no stack growth */
  break;
}

/* Opcode: If P1 P2 *
**
** Pop a single boolean from the stack.  If the boolean popped is
** true, then jump to p2.  Otherwise continue to the next instruction.
................................................................................
** false, then jump to p2.  Otherwise continue to the next instruction.
** An integer is false if zero and true otherwise.  A string is
** false if it has zero length and true otherwise.
**
** If the value popped of the stack is NULL, then take the jump if P1
** is true and fall through if P1 is false.
*/
case OP_If:                 /* no stack growth */
case OP_IfNot: {            /* no stack growth */
  int c;
  assert( pTos>=p->aStack );
  if( pTos->flags & MEM_Null ){
    c = pOp->p1;
  }else{
    c = sqlite3VdbeIntValue(pTos);
    if( pOp->opcode==OP_IfNot ) c = !c;
................................................................................

/* Opcode: IsNull P1 P2 *
**
** If any of the top abs(P1) values on the stack are NULL, then jump
** to P2.  Pop the stack P1 times if P1>0.   If P1<0 leave the stack
** unchanged.
*/
case OP_IsNull: {            /* same as TK_ISNULL, no stack growth */
  int i, cnt;
  Mem *pTerm;
  cnt = pOp->p1;
  if( cnt<0 ) cnt = -cnt;
  pTerm = &pTos[1-cnt];
  assert( pTerm>=p->aStack );
  for(i=0; i<cnt; i++, pTerm++){
................................................................................

/* Opcode: NotNull P1 P2 *
**
** Jump to P2 if the top P1 values on the stack are all not NULL.  Pop the
** stack if P1 times if P1 is greater than zero.  If P1 is less than
** zero then leave the stack unchanged.
*/
case OP_NotNull: {            /* same as TK_NOTNULL, no stack growth */
  int i, cnt;
  cnt = pOp->p1;
  if( cnt<0 ) cnt = -cnt;
  assert( &pTos[1-cnt] >= p->aStack );
  for(i=0; i<cnt && (pTos[1+i-cnt].flags & MEM_Null)==0; i++){}
  if( i>=cnt ) pc = pOp->p2-1;
  if( pOp->p1>0 ) popStack(&pTos, cnt);
................................................................................
** opcode must be called to set the number of fields in the table.
**
** This opcode sets the number of columns for cursor P1 to P2.
**
** If OP_KeyAsData is to be applied to cursor P1, it must be executed
** before this op-code.
*/
case OP_SetNumColumns: {       /* no stack growth */
  Cursor *pC;
  assert( (pOp->p1)<p->nCursor );
  assert( p->apCsr[pOp->p1]!=0 );
  pC = p->apCsr[pOp->p1];
  pC->nField = pOp->p2;
  if( (!pC->keyAsData && pC->zeroData) || (pC->keyAsData && pC->intKey) ){
    rc = SQLITE_CORRUPT;
................................................................................
** entire transaction.  The statement transaction will automatically
** commit when the VDBE halts.
**
** The statement is begun on the database file with index P1.  The main
** database file has an index of 0 and the file used for temporary tables
** has an index of 1.
*/
case OP_Statement: {       /* no stack growth */
  int i = pOp->p1;
  Btree *pBt;
  if( i>=0 && i<db->nDb && (pBt = db->aDb[i].pBt) && !(db->autoCommit) ){
    assert( sqlite3BtreeIsInTrans(pBt) );
    if( !sqlite3BtreeIsInStmt(pBt) ){
      rc = sqlite3BtreeBeginStmt(pBt);
    }
................................................................................
**
** Set the database auto-commit flag to P1 (1 or 0). If P2 is true, roll
** back any currently active btree transactions. If there are any active
** VMs (apart from this one), then the COMMIT or ROLLBACK statement fails.
**
** This instruction causes the VM to halt.
*/
case OP_AutoCommit: {       /* no stack growth */
  u8 i = pOp->p1;
  u8 rollback = pOp->p2;

  assert( i==1 || i==0 );
  assert( i==1 || rollback==0 );

  assert( db->activeVdbeCnt>0 );  /* At least this one VM is active */
................................................................................
** underway.  Starting a write transaction also creates a rollback journal. A
** write transaction must be started before any changes can be made to the
** database.  If P2 is 2 or greater then an EXCLUSIVE lock is also obtained
** on the file.
**
** If P2 is zero, then a read-lock is obtained on the database file.
*/
case OP_Transaction: {       /* no stack growth */
  int i = pOp->p1;
  Btree *pBt;

  assert( i>=0 && i<db->nDb );
  pBt = db->aDb[i].pBt;

  if( pBt ){
................................................................................
** P2==0 is the schema version.  P2==1 is the database format.
** P2==2 is the recommended pager cache size, and so forth.  P1==0 is
** the main database file and P1==1 is the database file used to store
** temporary tables.
**
** A transaction must be started before executing this opcode.
*/
case OP_SetCookie: {       /* no stack growth */
  Db *pDb;
  assert( pOp->p2<SQLITE_N_BTREE_META );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  pDb = &db->aDb[pOp->p1];
  assert( pDb->pBt!=0 );
  assert( pTos>=p->aStack );
  Integerify(pTos);
................................................................................
** This operation is used to detect when that the cookie has changed
** and that the current process needs to reread the schema.
**
** Either a transaction needs to have been started or an OP_Open needs
** to be executed (to establish a read lock) before this opcode is
** invoked.
*/
case OP_VerifyCookie: {       /* no stack growth */
  int iMeta;
  Btree *pBt;
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  pBt = db->aDb[pOp->p1].pBt;
  if( pBt ){
    rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&iMeta);
  }else{
................................................................................
**
** This instruction works just like OpenRead except that it opens the cursor
** in read/write mode.  For a given table, there can be one or more read-only
** cursors or a single read/write cursor but not both.
**
** See also OpenRead.
*/
case OP_OpenRead:          /* no stack growth */
case OP_OpenWrite: {       /* no stack growth */
  int i = pOp->p1;
  int p2 = pOp->p2;
  int wrFlag;
  Btree *pX;
  int iDb;
  Cursor *pCur;
  
................................................................................
** This opcode is used for tables that exist for the duration of a single
** SQL statement only.  Tables created using CREATE TEMPORARY TABLE
** are opened using OP_OpenRead or OP_OpenWrite.  "Temporary" in the
** context of this opcode means for the duration of a single SQL statement
** whereas "Temporary" in the context of CREATE TABLE means for the duration
** of the connection to the database.  Same word; different meanings.
*/
case OP_OpenTemp: {       /* no stack growth */
  int i = pOp->p1;
  Cursor *pCx;
  assert( i>=0 );
  pCx = allocateCursor(p, i);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  rc = sqlite3BtreeFactory(db, 0, 1, TEMP_PAGES, &pCx->pBt);
................................................................................
** row of data.  Any attempt to write a second row of data causes the
** first row to be deleted.  All data is deleted when the cursor is
** closed.
**
** A pseudo-table created by this opcode is useful for holding the
** NEW or OLD tables in a trigger.
*/
case OP_OpenPseudo: {       /* no stack growth */
  int i = pOp->p1;
  Cursor *pCx;
  assert( i>=0 );
  pCx = allocateCursor(p, i);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->pseudoTable = 1;
................................................................................
#endif

/* Opcode: Close P1 * *
**
** Close a cursor previously opened as P1.  If P1 is not
** currently open, this instruction is a no-op.
*/
case OP_Close: {       /* no stack growth */
  int i = pOp->p1;
  if( i>=0 && i<p->nCursor ){
    sqlite3VdbeFreeCursor(p->apCsr[i]);
    p->apCsr[i] = 0;
  }
  break;
}
................................................................................
** cursor P1 so that it points to the largest entry that is less than
** or equal to the key that was popped from the stack.
** If there are no records less than or eqal to the key and P2 is not zero,
** then jump to P2.
**
** See also: Found, NotFound, Distinct, MoveGt, MoveGe, MoveLt
*/
case OP_MoveLt:         /* no stack growth */
case OP_MoveLe:         /* no stack growth */
case OP_MoveGe:         /* no stack growth */
case OP_MoveGt: {       /* no stack growth */
  int i = pOp->p1;
  Cursor *pC;

  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
................................................................................
** record if it exists.  The key is popped from the stack.
**
** The difference between this operation and Distinct is that
** Distinct does not pop the key from the stack.
**
** See also: Distinct, Found, MoveTo, NotExists, IsUnique
*/
case OP_Distinct:       /* no stack growth */
case OP_NotFound:       /* no stack growth */
case OP_Found: {        /* no stack growth */
  int i = pOp->p1;
  int alreadyExists = 0;
  Cursor *pC;
  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pC = p->apCsr[i])->pCursor!=0 ){
................................................................................
** jump to P2.  If any entry does exist where the index string
** matches K but the record number is not R, then the record
** number for that entry is pushed onto the stack and control
** falls through to the next instruction.
**
** See also: Distinct, NotFound, NotExists, Found
*/
case OP_IsUnique: {        /* no stack growth */
  int i = pOp->p1;
  Mem *pNos = &pTos[-1];
  Cursor *pCx;
  BtCursor *pCrsr;
  i64 R;

  /* Pop the value R off the top of the stack
................................................................................
**
** The difference between this operation and NotFound is that this
** operation assumes the key is an integer and NotFound assumes it
** is a string.
**
** See also: Distinct, Found, MoveTo, NotFound, IsUnique
*/
case OP_NotExists: {        /* no stack growth */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
................................................................................
** created if it doesn't already exist or the data for an existing
** entry is overwritten.  The data is the value on the top of the
** stack.  The key is the next value down on the stack.  The key must
** be a string.  The stack is popped twice by this instruction.
**
** P1 may not be a pseudo-table opened using the OpenPseudo opcode.
*/
case OP_PutIntKey:          /* no stack growth */
case OP_PutStrKey: {        /* no stack growth */
  Mem *pNos = &pTos[-1];
  int i = pOp->p1;
  Cursor *pC;
  assert( pNos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( ((pC = p->apCsr[i])->pCursor!=0 || pC->pseudoTable) ){
................................................................................
** a record from within an Next loop.
**
** If the OPFLAG_NCHANGE flag of P2 is set, then the row change count is
** incremented (otherwise not).
**
** If P1 is a pseudo-table, then this instruction is a no-op.
*/
case OP_Delete: {        /* no stack growth */
  int i = pOp->p1;
  Cursor *pC;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( pC->pCursor!=0 ){
    rc = sqlite3VdbeCursorMoveto(pC);
................................................................................
/* Opcode: ResetCount P1 * *
**
** This opcode resets the VMs internal change counter to 0. If P1 is true,
** then the value of the change counter is copied to the database handle
** change counter (returned by subsequent calls to sqlite3_changes())
** before it is reset. This is used by trigger programs.
*/
case OP_ResetCount: {        /* no stack growth */
  if( pOp->p1 ){
    sqlite3VdbeSetChanges(db, p->nChange);
  }
  p->nChange = 0;
  break;
}

................................................................................
/* Opcode: KeyAsData P1 P2 *
**
** Turn the key-as-data mode for cursor P1 either on (if P2==1) or
** off (if P2==0).  In key-as-data mode, the OP_Column opcode pulls
** data off of the key rather than the data.  This is used for
** processing compound selects.
*/
case OP_KeyAsData: {        /* no stack growth */
  int i = pOp->p1;
  Cursor *pC;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  pC->keyAsData = pOp->p2;
  break;
................................................................................

/* Opcode: NullRow P1 * *
**
** Move the cursor P1 to a null row.  Any OP_Column operations
** that occur while the cursor is on the null row will always push 
** a NULL onto the stack.
*/
case OP_NullRow: {        /* no stack growth */
  int i = pOp->p1;
  Cursor *pC;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  pC->nullRow = 1;
................................................................................
**
** The next use of the Recno or Column or Next instruction for P1 
** will refer to the last entry in the database table or index.
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
*/
case OP_Last: {        /* no stack growth */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
................................................................................
**
** The next use of the Recno or Column or Next instruction for P1 
** will refer to the first entry in the database table or index.
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
*/
case OP_Rewind: {        /* no stack growth */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  int res;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
................................................................................
/* Opcode: Prev P1 P2 *
**
** Back up cursor P1 so that it points to the previous key/data pair in its
** table or index.  If there is no previous key/value pairs then fall through
** to the following instruction.  But if the cursor backup was successful,
** jump immediately to P2.
*/
case OP_Prev:          /* no stack growth */
case OP_Next: {        /* no stack growth */
  Cursor *pC;
  BtCursor *pCrsr;

  CHECK_FOR_INTERRUPT;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
................................................................................
** index P1.  Data for the entry is nil.
**
** If P2==1, then the key must be unique.  If the key is not unique,
** the program aborts with a SQLITE_CONSTRAINT error and the database
** is rolled back.  If P3 is not null, then it becomes part of the
** error message returned with the SQLITE_CONSTRAINT.
*/
case OP_IdxPut: {        /* no stack growth */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  assert( pTos->flags & MEM_Blob );
................................................................................
}

/* Opcode: IdxDelete P1 * *
**
** The top of the stack is an index key built using the MakeIdxKey opcode.
** This opcode removes that entry from the index.
*/
case OP_IdxDelete: {        /* no stack growth */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  assert( pTos>=p->aStack );
  assert( pTos->flags & MEM_Blob );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
................................................................................
** In either case, the stack is popped once.
**
** If P3 is the "+" string (or any other non-NULL string) then the
** index taken from the top of the stack is temporarily increased by
** an epsilon prior to the comparison.  This makes the opcode work
** like IdxLE.
*/
case OP_IdxLT:          /* no stack growth */
case OP_IdxGT:          /* no stack growth */
case OP_IdxGE: {        /* no stack growth */
  int i= pOp->p1;
  BtCursor *pCrsr;
  Cursor *pC;

  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  assert( pTos>=p->aStack );
................................................................................
** The top of the stack contains an index entry such as might be generated
** by the MakeIdxKey opcode.  This routine looks at the first P1 fields of
** that key.  If any of the first P1 fields are NULL, then a jump is made
** to address P2.  Otherwise we fall straight through.
**
** The index entry is always popped from the stack.
*/
case OP_IdxIsNull: {        /* no stack growth */
  int i = pOp->p1;
  int k, n;
  const char *z;
  u32 serial_type;

  assert( pTos>=p->aStack );
  assert( pTos->flags & MEM_Blob );
................................................................................
**
** The table being clear is in the main database file if P2==0.  If
** P2==1 then the table to be clear is in the auxiliary database file
** that is used to store tables create using CREATE TEMPORARY TABLE.
**
** See also: Destroy
*/
case OP_Clear: {        /* no stack growth */
  rc = sqlite3BtreeClearTable(db->aDb[pOp->p2].pBt, pOp->p1);
  break;
}

/* Opcode: CreateTable P1 * *
**
** Allocate a new table in the main database file if P2==0 or in the
................................................................................
**
** Read and parse all entries from the SQLITE_MASTER table of database P1
** that match the WHERE clause P3.
**
** This opcode invokes the parser to create a new virtual machine,
** then runs the new virtual machine.  It is thus a reentrant opcode.
*/
case OP_ParseSchema: {        /* no stack growth */
  char *zSql;
  int iDb = pOp->p1;
  const char *zMaster;
  InitData initData;

  assert( iDb>=0 && iDb<db->nDb );
  if( !DbHasProperty(db, iDb, DB_SchemaLoaded) ) break;
................................................................................
/* Opcode: DropTable P1 * P3
**
** Remove the internal (in-memory) data structures that describe
** the table named P3 in database P1.  This is called after a table
** is dropped in order to keep the internal representation of the
** schema consistent with what is on disk.
*/
case OP_DropTable: {        /* no stack growth */
  sqlite3UnlinkAndDeleteTable(db, pOp->p1, pOp->p3);
  break;
}

/* Opcode: DropIndex P1 * P3
**
** Remove the internal (in-memory) data structures that describe
** the index named P3 in database P1.  This is called after an index
** is dropped in order to keep the internal representation of the
** schema consistent with what is on disk.
*/
case OP_DropIndex: {        /* no stack growth */
  sqlite3UnlinkAndDeleteIndex(db, pOp->p1, pOp->p3);
  break;
}

/* Opcode: DropTrigger P1 * P3
**
** Remove the internal (in-memory) data structures that describe
** the trigger named P3 in database P1.  This is called after a trigger
** is dropped in order to keep the internal representation of the
** schema consistent with what is on disk.
*/
case OP_DropTrigger: {        /* no stack growth */
  sqlite3UnlinkAndDeleteTrigger(db, pOp->p1, pOp->p3);
  break;
}


#ifndef SQLITE_OMIT_INTEGRITY_CHECK
/* Opcode: IntegrityCk * P2 *
................................................................................
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */

/* Opcode: ListWrite * * *
**
** Write the integer on the top of the stack
** into the temporary storage list.
*/
case OP_ListWrite: {        /* no stack growth */
  Keylist *pKeylist;
  assert( pTos>=p->aStack );
  pKeylist = p->pList;
  if( pKeylist==0 || pKeylist->nUsed>=pKeylist->nKey ){
    pKeylist = sqliteMallocRaw( sizeof(Keylist)+999*sizeof(pKeylist->aKey[0]) );
    if( pKeylist==0 ) goto no_mem;
    pKeylist->nKey = 1000;
................................................................................
  break;
}

/* Opcode: ListRewind * * *
**
** Rewind the temporary buffer back to the beginning.
*/
case OP_ListRewind: {        /* no stack growth */
  /* What this opcode codes, really, is reverse the order of the
  ** linked list of Keylist structures so that they are read out
  ** in the same order that they were read in. */
  Keylist *pRev, *pTop;
  pRev = 0;
  while( p->pList ){
    pTop = p->pList;
................................................................................
  break;
}

/* Opcode: ListReset * * *
**
** Reset the temporary storage buffer so that it holds nothing.
*/
case OP_ListReset: {        /* no stack growth */
  if( p->pList ){
    sqlite3VdbeKeylistFree(p->pList);
    p->pList = 0;
  }
  break;
}

................................................................................
#ifndef SQLITE_OMIT_SUBQUERY
/* Opcode: AggContextPush * * * 
**
** Save the state of the current aggregator. It is restored an 
** AggContextPop opcode.
** 
*/
case OP_AggContextPush: {        /* no stack growth */
  p->pAgg++;
  assert( p->pAgg<&p->apAgg[p->nAgg] );
  break;
}

/* Opcode: AggContextPop * * *
**
** Restore the aggregator to the state it was in when AggContextPush
** was last called. Any data in the current aggregator is deleted.
*/
case OP_AggContextPop: {        /* no stack growth */
  p->pAgg--;
  assert( p->pAgg>=p->apAgg );
  break;
}
#endif

#ifndef SQLITE_OMIT_TRIGGER
/* Opcode: ContextPush * * * 
**
** Save the current Vdbe context such that it can be restored by a ContextPop
** opcode. The context stores the last insert row id, the last statement change
** count, and the current statement change count.
*/
case OP_ContextPush: {        /* no stack growth */
  int i = p->contextStackTop++;
  Context *pContext;

  assert( i>=0 );
  /* FIX ME: This should be allocated as part of the vdbe at compile-time */
  if( i>=p->contextStackDepth ){
    p->contextStackDepth = i+1;
................................................................................

/* Opcode: ContextPop * * * 
**
** Restore the Vdbe context to the state it was in when contextPush was last
** executed. The context stores the last insert row id, the last statement
** change count, and the current statement change count.
*/
case OP_ContextPop: {        /* no stack growth */
  Context *pContext = &p->contextStack[--p->contextStackTop];
  assert( p->contextStackTop>=0 );
  db->lastRowid = pContext->lastRowid;
  p->nChange = pContext->nChange;
  sqlite3VdbeKeylistFree(p->pList);
  p->pList = pContext->pList;
  break;
................................................................................

/* Opcode: SortPut * * *
**
** The TOS is the key and the NOS is the data.  Pop both from the stack
** and put them on the sorter.  The key and data should have been
** made using the MakeRecord opcode.
*/
case OP_SortPut: {        /* no stack growth */
  Mem *pNos = &pTos[-1];
  Sorter *pSorter;
  assert( pNos>=p->aStack );
  if( Dynamicify(pTos, db->enc) ) goto no_mem;
  pSorter = sqliteMallocRaw( sizeof(Sorter) );
  if( pSorter==0 ) goto no_mem;
  pSorter->pNext = p->pSort;
................................................................................

/* Opcode: Sort * * P3
**
** Sort all elements on the sorter.  The algorithm is a
** mergesort.  The P3 argument is a pointer to a KeyInfo structure
** that describes the keys to be sorted.
*/
case OP_Sort: {        /* no stack growth */
  int i;
  KeyInfo *pKeyInfo = (KeyInfo*)pOp->p3;
  Sorter *pElem;
  Sorter *apSorter[NSORT];
  sqlite3_sort_count++;
  pKeyInfo->enc = p->db->enc;
  for(i=0; i<NSORT; i++){
................................................................................
  break;
}

/* Opcode: SortReset * * *
**
** Remove any elements that remain on the sorter.
*/
case OP_SortReset: {        /* no stack growth */
  sqlite3VdbeSorterReset(p);
  break;
}

/* Opcode: MemStore P1 P2 *
**
** Write the top of the stack into memory location P1.
................................................................................
** P1 should be a small integer since space is allocated
** for all memory locations between 0 and P1 inclusive.
**
** After the data is stored in the memory location, the
** stack is popped once if P2 is 1.  If P2 is zero, then
** the original data remains on the stack.
*/
case OP_MemStore: {        /* no stack growth */
  assert( pTos>=p->aStack );
  assert( pOp->p1>=0 && pOp->p1<p->nMem );
  rc = sqlite3VdbeMemMove(&p->aMem[pOp->p1], pTos);
  pTos--;

  /* If P2 is 0 then fall thru to the next opcode, OP_MemLoad, that will
  ** restore the top of the stack to its original value.
................................................................................
**
** Set the value of memory cell P1 to the maximum of its current value
** and the value on the top of the stack.  The stack is unchanged.
**
** This instruction throws an error if the memory cell is not initially
** an integer.
*/
case OP_MemMax: {        /* no stack growth */
  int i = pOp->p1;
  Mem *pMem;
  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nMem );
  pMem = &p->aMem[i];
  Integerify(pMem);
  Integerify(pTos);
................................................................................
** Increment the integer valued memory cell P1 by 1.  If P2 is not zero
** and the result after the increment is exactly 1, then jump
** to P2.
**
** This instruction throws an error if the memory cell is not initially
** an integer.
*/
case OP_MemIncr: {        /* no stack growth */
  int i = pOp->p1;
  Mem *pMem;
  assert( i>=0 && i<p->nMem );
  pMem = &p->aMem[i];
  assert( pMem->flags==MEM_Int );
  pMem->i++;
  if( pOp->p2>0 && pMem->i==1 ){
................................................................................
}

/* Opcode: IfMemPos P1 P2 *
**
** If the value of memory cell P1 is 1 or greater, jump to P2. This
** opcode assumes that memory cell P1 holds an integer value.
*/
case OP_IfMemPos: {        /* no stack growth */
  int i = pOp->p1;
  Mem *pMem;
  assert( i>=0 && i<p->nMem );
  pMem = &p->aMem[i];
  assert( pMem->flags==MEM_Int );
  if( pMem->i>0 ){
     pc = pOp->p2 - 1;
................................................................................
** data. Future aggregator elements will contain P2 values each and be sorted
** using the KeyInfo structure pointed to by P3.
**
** If P1 is non-zero, then only a single aggregator row is available (i.e.
** there is no GROUP BY expression). In this case it is illegal to invoke
** OP_AggFocus.
*/
case OP_AggReset: {        /* no stack growth */
  assert( !pOp->p3 || pOp->p3type==P3_KEYINFO );
  if( pOp->p1 ){
    rc = sqlite3VdbeAggReset(0, p->pAgg, (KeyInfo *)pOp->p3);
    p->pAgg->nMem = pOp->p2;    /* Agg.nMem is used by AggInsert() */
    rc = AggInsert(p->pAgg, 0, 0);
  }else{
    rc = sqlite3VdbeAggReset(db, p->pAgg, (KeyInfo *)pOp->p3);
................................................................................

/* Opcode: AggInit * P2 P3
**
** Initialize the function parameters for an aggregate function.
** The aggregate will operate out of aggregate column P2.
** P3 is a pointer to the FuncDef structure for the function.
*/
case OP_AggInit: {        /* no stack growth */
  int i = pOp->p2;
  assert( i>=0 && i<p->pAgg->nMem );
  p->pAgg->apFunc[i] = (FuncDef*)pOp->p3;
  break;
}

/* Opcode: AggFunc * P2 P3
................................................................................
** structure that specifies the function.
**
** The top of the stack must be an integer which is the index of
** the aggregate column that corresponds to this aggregate function.
** Ideally, this index would be another parameter, but there are
** no free parameters left.  The integer is popped from the stack.
*/
case OP_AggFunc: {        /* no stack growth */
  int n = pOp->p2;
  int i;
  Mem *pMem, *pRec;
  sqlite3_context ctx;
  sqlite3_value **apVal;

  assert( n>=0 );
................................................................................
**
** The order of aggregator opcodes is important.  The order is:
** AggReset AggFocus AggNext.  In other words, you must execute
** AggReset first, then zero or more AggFocus operations, then
** zero or more AggNext operations.  You must not execute an AggFocus
** in between an AggNext and an AggReset.
*/
case OP_AggFocus: {        /* no stack growth */
  char *zKey;
  int nKey;
  int res;
  assert( pTos>=p->aStack );
  Stringify(pTos, db->enc);
  zKey = pTos->z;
  nKey = pTos->n;
................................................................................
}

/* Opcode: AggSet * P2 *
**
** Move the top of the stack into the P2-th field of the current
** aggregate.  String values are duplicated into new memory.
*/
case OP_AggSet: {        /* no stack growth */
  AggElem *pFocus;
  int i = pOp->p2;
  pFocus = p->pAgg->pCurrent;
  assert( pTos>=p->aStack );
  if( pFocus==0 ) goto no_mem;
  assert( i>=0 && i<p->pAgg->nMem );
  rc = sqlite3VdbeMemMove(&pFocus->aMem[i], pTos);
................................................................................
**
** The order of aggregator opcodes is important.  The order is:
** AggReset AggFocus AggNext.  In other words, you must execute
** AggReset first, then zero or more AggFocus operations, then
** zero or more AggNext operations.  You must not execute an AggFocus
** in between an AggNext and an AggReset.
*/
case OP_AggNext: {        /* no stack growth */
  int res;
  assert( rc==SQLITE_OK );
  CHECK_FOR_INTERRUPT;
  if( p->pAgg->searching==0 ){
    p->pAgg->searching = 1;
    if( p->pAgg->pCsr ){
      rc = sqlite3BtreeFirst(p->pAgg->pCsr, &res);
................................................................................

/* Opcode: Vacuum * * *
**
** Vacuum the entire database.  This opcode will cause other virtual
** machines to be created and run.  It may not be called from within
** a transaction.
*/
case OP_Vacuum: {        /* no stack growth */
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse; 
  rc = sqlite3RunVacuum(&p->zErrMsg, db);
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
  break;
}

/* Opcode: Expire P1 * *
................................................................................
** Cause precompiled statements to become expired. An expired statement
** fails with an error code of SQLITE_SCHEMA if it is ever executed 
** (via sqlite3_step()).
** 
** If P1 is 0, then all SQL statements become expired. If P1 is non-zero,
** then only the currently executing statement is affected. 
*/
case OP_Expire: {        /* no stack growth */
  if( !pOp->p1 ){
    sqlite3ExpirePreparedStatements(db);
  }else{
    p->expired = 1;
  }
  break;
}







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....
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
....
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
....
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
....
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
....
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
....
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
....
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
....
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
....
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
....
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
....
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
....
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
....
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
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4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
....
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
....
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
....
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
....
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
....
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
....
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
....
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
....
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
....
4310
4311
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4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
....
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
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4347
4348
....
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
....
4410
4411
4412
4413
4414
4415
4416
4417
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4419
4420
4421
4422
4423
4424
....
4444
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4451
4452
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4454
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4457
4458
....
4509
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4522
4523
....
4570
4571
4572
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4577
4578
4579
4580
4581
4582
4583
4584
....
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.463 2005/03/29 13:07:00 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
      }
      nProgressOps++;
    }
#endif

#ifndef NDEBUG
    /* This is to check that the return value of static function
    ** opcodeNoPush() (see vdbeaux.c) returns values that match the
    ** implementation of the virtual machine in this file. If
    ** opcodeNoPush() returns non-zero, then the stack is guarenteed
    ** not to grow when the opcode is executed. If it returns zero, then
    ** the stack may grow by at most 1.
    **
    ** The global wrapper function sqlite3VdbeOpcodeUsesStack() is not 
    ** available if NDEBUG is defined at build time.
    */ 
    pStackLimit = pTos;
    if( !sqlite3VdbeOpcodeNoPush(pOp->opcode) ){
      pStackLimit++;
    }
#endif

    switch( pOp->opcode ){

/*****************************************************************************
................................................................................
** will be filled with #defines that give unique integer values to each
** opcode and the opcodes.c file is filled with an array of strings where
** each string is the symbolic name for the corresponding opcode.  If the
** case statement is followed by a comment of the form "/# same as ... #/"
** that comment is used to determine the particular value of the opcode.
**
** If a comment on the same line as the "case OP_" construction contains
** the word "no-push", then the opcode is guarenteed not to grow the 
** vdbe stack when it is executed. See function opcode() in
** vdbeaux.c for details.
**
** Documentation about VDBE opcodes is generated by scanning this file
** for lines of that contain "Opcode:".  That line and all subsequent
** comment lines are used in the generation of the opcode.html documentation
** file.
**
................................................................................
/* Opcode:  Goto * P2 *
**
** An unconditional jump to address P2.
** The next instruction executed will be 
** the one at index P2 from the beginning of
** the program.
*/
case OP_Goto: {             /* no-push */
  CHECK_FOR_INTERRUPT;
  pc = pOp->p2 - 1;
  break;
}

/* Opcode:  Gosub * P2 *
**
................................................................................
** and then jump to address P2.
**
** The return address stack is of limited depth.  If too many
** OP_Gosub operations occur without intervening OP_Returns, then
** the return address stack will fill up and processing will abort
** with a fatal error.
*/
case OP_Gosub: {            /* no-push */
  assert( p->returnDepth<sizeof(p->returnStack)/sizeof(p->returnStack[0]) );
  p->returnStack[p->returnDepth++] = pc+1;
  pc = pOp->p2 - 1;
  break;
}

/* Opcode:  Return * * *
**
** Jump immediately to the next instruction after the last unreturned
** OP_Gosub.  If an OP_Return has occurred for all OP_Gosubs, then
** processing aborts with a fatal error.
*/
case OP_Return: {           /* no-push */
  assert( p->returnDepth>0 );
  p->returnDepth--;
  pc = p->returnStack[p->returnDepth] - 1;
  break;
}

/* Opcode:  Halt P1 P2 *
................................................................................
** then back out all changes that have occurred during this execution of the
** VDBE, but do not rollback the transaction. 
**
** There is an implied "Halt 0 0 0" instruction inserted at the very end of
** every program.  So a jump past the last instruction of the program
** is the same as executing Halt.
*/
case OP_Halt: {            /* no-push */
  p->pTos = pTos;
  p->rc = pOp->p1;
  p->pc = pc;
  p->errorAction = pOp->p2;
  if( pOp->p3 ){
    sqlite3SetString(&p->zErrMsg, pOp->p3, (char*)0);
  }
................................................................................
  break;
}

/* Opcode: Pop P1 * *
**
** P1 elements are popped off of the top of stack and discarded.
*/
case OP_Pop: {            /* no-push */
  assert( pOp->p1>=0 );
  popStack(&pTos, pOp->p1);
  assert( pTos>=&p->aStack[-1] );
  break;
}

/* Opcode: Dup P1 P2 *
................................................................................
** the stack and pushed back on top of the stack.  The
** top of the stack is element 0, so "Pull 0 0 0" is
** a no-op.  "Pull 1 0 0" swaps the top two elements of
** the stack.
**
** See also the Dup instruction.
*/
case OP_Pull: {            /* no-push */
  Mem *pFrom = &pTos[-pOp->p1];
  int i;
  Mem ts;

  ts = *pFrom;
  Deephemeralize(pTos);
  for(i=0; i<pOp->p1; i++, pFrom++){
................................................................................

/* Opcode: Push P1 * *
**
** Overwrite the value of the P1-th element down on the
** stack (P1==0 is the top of the stack) with the value
** of the top of the stack.  Then pop the top of the stack.
*/
case OP_Push: {            /* no-push */
  Mem *pTo = &pTos[-pOp->p1];

  assert( pTo>=p->aStack );
  sqlite3VdbeMemMove(pTo, pTos);
  pTos--;
  break;
}
................................................................................

/* Opcode: Callback P1 * *
**
** Pop P1 values off the stack and form them into an array.  Then
** invoke the callback function using the newly formed array as the
** 3rd parameter.
*/
case OP_Callback: {            /* no-push */
  int i;
  assert( p->nResColumn==pOp->p1 );

  for(i=0; i<pOp->p1; i++){
    Mem *pVal = &pTos[0-i];
    sqlite3VdbeMemNulTerminate(pVal);
    storeTypeInfo(pVal, db->enc);
................................................................................
** first (what was on top of the stack) from the second (the
** next on stack)
** and push the remainder after division onto the stack.  If either element
** is a string then it is converted to a double using the atof()
** function before the division.  Division by zero returns NULL.
** If either operand is NULL, the result is NULL.
*/
case OP_Add:                   /* same as TK_PLUS, no-push */
case OP_Subtract:              /* same as TK_MINUS, no-push */
case OP_Multiply:              /* same as TK_STAR, no-push */
case OP_Divide:                /* same as TK_SLASH, no-push */
case OP_Remainder: {           /* same as TK_REM, no-push */
  Mem *pNos = &pTos[-1];
  assert( pNos>=p->aStack );
  if( ((pTos->flags | pNos->flags) & MEM_Null)!=0 ){
    Release(pTos);
    pTos--;
    Release(pTos);
    pTos->flags = MEM_Null;
................................................................................
** be returned. This is used by the built-in min(), max() and nullif()
** functions.
**
** The interface used by the implementation of the aforementioned functions
** to retrieve the collation sequence set by this opcode is not available
** publicly, only to user functions defined in func.c.
*/
case OP_CollSeq: {             /* no-push */
  assert( pOp->p3type==P3_COLLSEQ );
  break;
}

/* Opcode: Function P1 P2 P3
**
** Invoke a user function (P3 is a pointer to a Function structure that
................................................................................
/* Opcode: ShiftRight * * *
**
** Pop the top two elements from the stack.  Convert both elements
** to integers.  Push back onto the stack the second element shifted
** right by N bits where N is the top element on the stack.
** If either operand is NULL, the result is NULL.
*/
case OP_BitAnd:                 /* same as TK_BITAND, no-push */
case OP_BitOr:                  /* same as TK_BITOR, no-push */
case OP_ShiftLeft:              /* same as TK_LSHIFT, no-push */
case OP_ShiftRight: {           /* same as TK_RSHIFT, no-push */
  Mem *pNos = &pTos[-1];
  int a, b;

  assert( pNos>=p->aStack );
  if( (pTos->flags | pNos->flags) & MEM_Null ){
    popStack(&pTos, 2);
    pTos++;
................................................................................
/* Opcode: AddImm  P1 * *
** 
** Add the value P1 to whatever is on top of the stack.  The result
** is always an integer.
**
** To force the top of the stack to be an integer, just add 0.
*/
case OP_AddImm: {            /* no-push */
  assert( pTos>=p->aStack );
  Integerify(pTos);
  pTos->i += pOp->p1;
  break;
}

/* Opcode: ForceInt P1 P2 *
................................................................................
** the stack is not numeric (meaning that is is a NULL or a string that
** does not look like an integer or floating point number) then pop the
** stack and jump to P2.  If the top of the stack is numeric then
** convert it into the least integer that is greater than or equal to its
** current value if P1==0, or to the least integer that is strictly
** greater than its current value if P1==1.
*/
case OP_ForceInt: {            /* no-push */
  int v;
  assert( pTos>=p->aStack );
  applyAffinity(pTos, SQLITE_AFF_INTEGER, db->enc);
  if( (pTos->flags & (MEM_Int|MEM_Real))==0 ){
    Release(pTos);
    pTos--;
    pc = pOp->p2 - 1;
................................................................................
** with out data loss, then jump immediately to P2, or if P2==0
** raise an SQLITE_MISMATCH exception.
**
** If the top of the stack is not an integer and P2 is not zero and
** P1 is 1, then the stack is popped.  In all other cases, the depth
** of the stack is unchanged.
*/
case OP_MustBeInt: {            /* no-push */
  assert( pTos>=p->aStack );
  applyAffinity(pTos, SQLITE_AFF_INTEGER, db->enc);
  if( (pTos->flags & MEM_Int)==0 ){
    if( pOp->p2==0 ){
      rc = SQLITE_MISMATCH;
      goto abort_due_to_error;
    }else{
................................................................................
*/
/* Opcode: Ge P1 P2 P3
**
** This works just like the Eq opcode except that the jump is taken if
** the 2nd element down on the stack is greater than or equal to the
** top of the stack.  See the Eq opcode for additional information.
*/
case OP_Eq:               /* same as TK_EQ, no-push */
case OP_Ne:               /* same as TK_NE, no-push */
case OP_Lt:               /* same as TK_LT, no-push */
case OP_Le:               /* same as TK_LE, no-push */
case OP_Gt:               /* same as TK_GT, no-push */
case OP_Ge: {             /* same as TK_GE, no-push */
  Mem *pNos;
  int flags;
  int res;
  char affinity;

  pNos = &pTos[-1];
  flags = pTos->flags|pNos->flags;
................................................................................
*/
/* Opcode: Or * * *
**
** Pop two values off the stack.  Take the logical OR of the
** two values and push the resulting boolean value back onto the
** stack. 
*/
case OP_And:              /* same as TK_AND, no-push */
case OP_Or: {             /* same as TK_OR, no-push */
  Mem *pNos = &pTos[-1];
  int v1, v2;    /* 0==TRUE, 1==FALSE, 2==UNKNOWN or NULL */

  assert( pNos>=p->aStack );
  if( pTos->flags & MEM_Null ){
    v1 = 2;
  }else{
................................................................................
*/
/* Opcode: AbsValue * * *
**
** Treat the top of the stack as a numeric quantity.  Replace it
** with its absolute value. If the top of the stack is NULL
** its value is unchanged.
*/
case OP_Negative:              /* same as TK_UMINUS, no-push */
case OP_AbsValue: {
  assert( pTos>=p->aStack );
  if( pTos->flags & MEM_Real ){
    Release(pTos);
    if( pOp->opcode==OP_Negative || pTos->r<0.0 ){
      pTos->r = -pTos->r;
    }
................................................................................

/* Opcode: Not * * *
**
** Interpret the top of the stack as a boolean value.  Replace it
** with its complement.  If the top of the stack is NULL its value
** is unchanged.
*/
case OP_Not: {                /* same as TK_NOT, no-push */
  assert( pTos>=p->aStack );
  if( pTos->flags & MEM_Null ) break;  /* Do nothing to NULLs */
  Integerify(pTos);
  assert( (pTos->flags & MEM_Dyn)==0 );
  pTos->i = !pTos->i;
  pTos->flags = MEM_Int;
  break;
................................................................................

/* Opcode: BitNot * * *
**
** Interpret the top of the stack as an value.  Replace it
** with its ones-complement.  If the top of the stack is NULL its
** value is unchanged.
*/
case OP_BitNot: {             /* same as TK_BITNOT, no-push */
  assert( pTos>=p->aStack );
  if( pTos->flags & MEM_Null ) break;  /* Do nothing to NULLs */
  Integerify(pTos);
  assert( (pTos->flags & MEM_Dyn)==0 );
  pTos->i = ~pTos->i;
  pTos->flags = MEM_Int;
  break;
................................................................................
}

/* Opcode: Noop * * *
**
** Do nothing.  This instruction is often useful as a jump
** destination.
*/
case OP_Noop: {            /* no-push */
  break;
}

/* Opcode: If P1 P2 *
**
** Pop a single boolean from the stack.  If the boolean popped is
** true, then jump to p2.  Otherwise continue to the next instruction.
................................................................................
** false, then jump to p2.  Otherwise continue to the next instruction.
** An integer is false if zero and true otherwise.  A string is
** false if it has zero length and true otherwise.
**
** If the value popped of the stack is NULL, then take the jump if P1
** is true and fall through if P1 is false.
*/
case OP_If:                 /* no-push */
case OP_IfNot: {            /* no-push */
  int c;
  assert( pTos>=p->aStack );
  if( pTos->flags & MEM_Null ){
    c = pOp->p1;
  }else{
    c = sqlite3VdbeIntValue(pTos);
    if( pOp->opcode==OP_IfNot ) c = !c;
................................................................................

/* Opcode: IsNull P1 P2 *
**
** If any of the top abs(P1) values on the stack are NULL, then jump
** to P2.  Pop the stack P1 times if P1>0.   If P1<0 leave the stack
** unchanged.
*/
case OP_IsNull: {            /* same as TK_ISNULL, no-push */
  int i, cnt;
  Mem *pTerm;
  cnt = pOp->p1;
  if( cnt<0 ) cnt = -cnt;
  pTerm = &pTos[1-cnt];
  assert( pTerm>=p->aStack );
  for(i=0; i<cnt; i++, pTerm++){
................................................................................

/* Opcode: NotNull P1 P2 *
**
** Jump to P2 if the top P1 values on the stack are all not NULL.  Pop the
** stack if P1 times if P1 is greater than zero.  If P1 is less than
** zero then leave the stack unchanged.
*/
case OP_NotNull: {            /* same as TK_NOTNULL, no-push */
  int i, cnt;
  cnt = pOp->p1;
  if( cnt<0 ) cnt = -cnt;
  assert( &pTos[1-cnt] >= p->aStack );
  for(i=0; i<cnt && (pTos[1+i-cnt].flags & MEM_Null)==0; i++){}
  if( i>=cnt ) pc = pOp->p2-1;
  if( pOp->p1>0 ) popStack(&pTos, cnt);
................................................................................
** opcode must be called to set the number of fields in the table.
**
** This opcode sets the number of columns for cursor P1 to P2.
**
** If OP_KeyAsData is to be applied to cursor P1, it must be executed
** before this op-code.
*/
case OP_SetNumColumns: {       /* no-push */
  Cursor *pC;
  assert( (pOp->p1)<p->nCursor );
  assert( p->apCsr[pOp->p1]!=0 );
  pC = p->apCsr[pOp->p1];
  pC->nField = pOp->p2;
  if( (!pC->keyAsData && pC->zeroData) || (pC->keyAsData && pC->intKey) ){
    rc = SQLITE_CORRUPT;
................................................................................
** entire transaction.  The statement transaction will automatically
** commit when the VDBE halts.
**
** The statement is begun on the database file with index P1.  The main
** database file has an index of 0 and the file used for temporary tables
** has an index of 1.
*/
case OP_Statement: {       /* no-push */
  int i = pOp->p1;
  Btree *pBt;
  if( i>=0 && i<db->nDb && (pBt = db->aDb[i].pBt) && !(db->autoCommit) ){
    assert( sqlite3BtreeIsInTrans(pBt) );
    if( !sqlite3BtreeIsInStmt(pBt) ){
      rc = sqlite3BtreeBeginStmt(pBt);
    }
................................................................................
**
** Set the database auto-commit flag to P1 (1 or 0). If P2 is true, roll
** back any currently active btree transactions. If there are any active
** VMs (apart from this one), then the COMMIT or ROLLBACK statement fails.
**
** This instruction causes the VM to halt.
*/
case OP_AutoCommit: {       /* no-push */
  u8 i = pOp->p1;
  u8 rollback = pOp->p2;

  assert( i==1 || i==0 );
  assert( i==1 || rollback==0 );

  assert( db->activeVdbeCnt>0 );  /* At least this one VM is active */
................................................................................
** underway.  Starting a write transaction also creates a rollback journal. A
** write transaction must be started before any changes can be made to the
** database.  If P2 is 2 or greater then an EXCLUSIVE lock is also obtained
** on the file.
**
** If P2 is zero, then a read-lock is obtained on the database file.
*/
case OP_Transaction: {       /* no-push */
  int i = pOp->p1;
  Btree *pBt;

  assert( i>=0 && i<db->nDb );
  pBt = db->aDb[i].pBt;

  if( pBt ){
................................................................................
** P2==0 is the schema version.  P2==1 is the database format.
** P2==2 is the recommended pager cache size, and so forth.  P1==0 is
** the main database file and P1==1 is the database file used to store
** temporary tables.
**
** A transaction must be started before executing this opcode.
*/
case OP_SetCookie: {       /* no-push */
  Db *pDb;
  assert( pOp->p2<SQLITE_N_BTREE_META );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  pDb = &db->aDb[pOp->p1];
  assert( pDb->pBt!=0 );
  assert( pTos>=p->aStack );
  Integerify(pTos);
................................................................................
** This operation is used to detect when that the cookie has changed
** and that the current process needs to reread the schema.
**
** Either a transaction needs to have been started or an OP_Open needs
** to be executed (to establish a read lock) before this opcode is
** invoked.
*/
case OP_VerifyCookie: {       /* no-push */
  int iMeta;
  Btree *pBt;
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  pBt = db->aDb[pOp->p1].pBt;
  if( pBt ){
    rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&iMeta);
  }else{
................................................................................
**
** This instruction works just like OpenRead except that it opens the cursor
** in read/write mode.  For a given table, there can be one or more read-only
** cursors or a single read/write cursor but not both.
**
** See also OpenRead.
*/
case OP_OpenRead:          /* no-push */
case OP_OpenWrite: {       /* no-push */
  int i = pOp->p1;
  int p2 = pOp->p2;
  int wrFlag;
  Btree *pX;
  int iDb;
  Cursor *pCur;
  
................................................................................
** This opcode is used for tables that exist for the duration of a single
** SQL statement only.  Tables created using CREATE TEMPORARY TABLE
** are opened using OP_OpenRead or OP_OpenWrite.  "Temporary" in the
** context of this opcode means for the duration of a single SQL statement
** whereas "Temporary" in the context of CREATE TABLE means for the duration
** of the connection to the database.  Same word; different meanings.
*/
case OP_OpenTemp: {       /* no-push */
  int i = pOp->p1;
  Cursor *pCx;
  assert( i>=0 );
  pCx = allocateCursor(p, i);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  rc = sqlite3BtreeFactory(db, 0, 1, TEMP_PAGES, &pCx->pBt);
................................................................................
** row of data.  Any attempt to write a second row of data causes the
** first row to be deleted.  All data is deleted when the cursor is
** closed.
**
** A pseudo-table created by this opcode is useful for holding the
** NEW or OLD tables in a trigger.
*/
case OP_OpenPseudo: {       /* no-push */
  int i = pOp->p1;
  Cursor *pCx;
  assert( i>=0 );
  pCx = allocateCursor(p, i);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->pseudoTable = 1;
................................................................................
#endif

/* Opcode: Close P1 * *
**
** Close a cursor previously opened as P1.  If P1 is not
** currently open, this instruction is a no-op.
*/
case OP_Close: {       /* no-push */
  int i = pOp->p1;
  if( i>=0 && i<p->nCursor ){
    sqlite3VdbeFreeCursor(p->apCsr[i]);
    p->apCsr[i] = 0;
  }
  break;
}
................................................................................
** cursor P1 so that it points to the largest entry that is less than
** or equal to the key that was popped from the stack.
** If there are no records less than or eqal to the key and P2 is not zero,
** then jump to P2.
**
** See also: Found, NotFound, Distinct, MoveGt, MoveGe, MoveLt
*/
case OP_MoveLt:         /* no-push */
case OP_MoveLe:         /* no-push */
case OP_MoveGe:         /* no-push */
case OP_MoveGt: {       /* no-push */
  int i = pOp->p1;
  Cursor *pC;

  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
................................................................................
** record if it exists.  The key is popped from the stack.
**
** The difference between this operation and Distinct is that
** Distinct does not pop the key from the stack.
**
** See also: Distinct, Found, MoveTo, NotExists, IsUnique
*/
case OP_Distinct:       /* no-push */
case OP_NotFound:       /* no-push */
case OP_Found: {        /* no-push */
  int i = pOp->p1;
  int alreadyExists = 0;
  Cursor *pC;
  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pC = p->apCsr[i])->pCursor!=0 ){
................................................................................
** jump to P2.  If any entry does exist where the index string
** matches K but the record number is not R, then the record
** number for that entry is pushed onto the stack and control
** falls through to the next instruction.
**
** See also: Distinct, NotFound, NotExists, Found
*/
case OP_IsUnique: {        /* no-push */
  int i = pOp->p1;
  Mem *pNos = &pTos[-1];
  Cursor *pCx;
  BtCursor *pCrsr;
  i64 R;

  /* Pop the value R off the top of the stack
................................................................................
**
** The difference between this operation and NotFound is that this
** operation assumes the key is an integer and NotFound assumes it
** is a string.
**
** See also: Distinct, Found, MoveTo, NotFound, IsUnique
*/
case OP_NotExists: {        /* no-push */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
................................................................................
** created if it doesn't already exist or the data for an existing
** entry is overwritten.  The data is the value on the top of the
** stack.  The key is the next value down on the stack.  The key must
** be a string.  The stack is popped twice by this instruction.
**
** P1 may not be a pseudo-table opened using the OpenPseudo opcode.
*/
case OP_PutIntKey:          /* no-push */
case OP_PutStrKey: {        /* no-push */
  Mem *pNos = &pTos[-1];
  int i = pOp->p1;
  Cursor *pC;
  assert( pNos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( ((pC = p->apCsr[i])->pCursor!=0 || pC->pseudoTable) ){
................................................................................
** a record from within an Next loop.
**
** If the OPFLAG_NCHANGE flag of P2 is set, then the row change count is
** incremented (otherwise not).
**
** If P1 is a pseudo-table, then this instruction is a no-op.
*/
case OP_Delete: {        /* no-push */
  int i = pOp->p1;
  Cursor *pC;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( pC->pCursor!=0 ){
    rc = sqlite3VdbeCursorMoveto(pC);
................................................................................
/* Opcode: ResetCount P1 * *
**
** This opcode resets the VMs internal change counter to 0. If P1 is true,
** then the value of the change counter is copied to the database handle
** change counter (returned by subsequent calls to sqlite3_changes())
** before it is reset. This is used by trigger programs.
*/
case OP_ResetCount: {        /* no-push */
  if( pOp->p1 ){
    sqlite3VdbeSetChanges(db, p->nChange);
  }
  p->nChange = 0;
  break;
}

................................................................................
/* Opcode: KeyAsData P1 P2 *
**
** Turn the key-as-data mode for cursor P1 either on (if P2==1) or
** off (if P2==0).  In key-as-data mode, the OP_Column opcode pulls
** data off of the key rather than the data.  This is used for
** processing compound selects.
*/
case OP_KeyAsData: {        /* no-push */
  int i = pOp->p1;
  Cursor *pC;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  pC->keyAsData = pOp->p2;
  break;
................................................................................

/* Opcode: NullRow P1 * *
**
** Move the cursor P1 to a null row.  Any OP_Column operations
** that occur while the cursor is on the null row will always push 
** a NULL onto the stack.
*/
case OP_NullRow: {        /* no-push */
  int i = pOp->p1;
  Cursor *pC;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  pC->nullRow = 1;
................................................................................
**
** The next use of the Recno or Column or Next instruction for P1 
** will refer to the last entry in the database table or index.
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
*/
case OP_Last: {        /* no-push */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
................................................................................
**
** The next use of the Recno or Column or Next instruction for P1 
** will refer to the first entry in the database table or index.
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
*/
case OP_Rewind: {        /* no-push */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  int res;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
................................................................................
/* Opcode: Prev P1 P2 *
**
** Back up cursor P1 so that it points to the previous key/data pair in its
** table or index.  If there is no previous key/value pairs then fall through
** to the following instruction.  But if the cursor backup was successful,
** jump immediately to P2.
*/
case OP_Prev:          /* no-push */
case OP_Next: {        /* no-push */
  Cursor *pC;
  BtCursor *pCrsr;

  CHECK_FOR_INTERRUPT;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
................................................................................
** index P1.  Data for the entry is nil.
**
** If P2==1, then the key must be unique.  If the key is not unique,
** the program aborts with a SQLITE_CONSTRAINT error and the database
** is rolled back.  If P3 is not null, then it becomes part of the
** error message returned with the SQLITE_CONSTRAINT.
*/
case OP_IdxPut: {        /* no-push */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  assert( pTos->flags & MEM_Blob );
................................................................................
}

/* Opcode: IdxDelete P1 * *
**
** The top of the stack is an index key built using the MakeIdxKey opcode.
** This opcode removes that entry from the index.
*/
case OP_IdxDelete: {        /* no-push */
  int i = pOp->p1;
  Cursor *pC;
  BtCursor *pCrsr;
  assert( pTos>=p->aStack );
  assert( pTos->flags & MEM_Blob );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
................................................................................
** In either case, the stack is popped once.
**
** If P3 is the "+" string (or any other non-NULL string) then the
** index taken from the top of the stack is temporarily increased by
** an epsilon prior to the comparison.  This makes the opcode work
** like IdxLE.
*/
case OP_IdxLT:          /* no-push */
case OP_IdxGT:          /* no-push */
case OP_IdxGE: {        /* no-push */
  int i= pOp->p1;
  BtCursor *pCrsr;
  Cursor *pC;

  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  assert( pTos>=p->aStack );
................................................................................
** The top of the stack contains an index entry such as might be generated
** by the MakeIdxKey opcode.  This routine looks at the first P1 fields of
** that key.  If any of the first P1 fields are NULL, then a jump is made
** to address P2.  Otherwise we fall straight through.
**
** The index entry is always popped from the stack.
*/
case OP_IdxIsNull: {        /* no-push */
  int i = pOp->p1;
  int k, n;
  const char *z;
  u32 serial_type;

  assert( pTos>=p->aStack );
  assert( pTos->flags & MEM_Blob );
................................................................................
**
** The table being clear is in the main database file if P2==0.  If
** P2==1 then the table to be clear is in the auxiliary database file
** that is used to store tables create using CREATE TEMPORARY TABLE.
**
** See also: Destroy
*/
case OP_Clear: {        /* no-push */
  rc = sqlite3BtreeClearTable(db->aDb[pOp->p2].pBt, pOp->p1);
  break;
}

/* Opcode: CreateTable P1 * *
**
** Allocate a new table in the main database file if P2==0 or in the
................................................................................
**
** Read and parse all entries from the SQLITE_MASTER table of database P1
** that match the WHERE clause P3.
**
** This opcode invokes the parser to create a new virtual machine,
** then runs the new virtual machine.  It is thus a reentrant opcode.
*/
case OP_ParseSchema: {        /* no-push */
  char *zSql;
  int iDb = pOp->p1;
  const char *zMaster;
  InitData initData;

  assert( iDb>=0 && iDb<db->nDb );
  if( !DbHasProperty(db, iDb, DB_SchemaLoaded) ) break;
................................................................................
/* Opcode: DropTable P1 * P3
**
** Remove the internal (in-memory) data structures that describe
** the table named P3 in database P1.  This is called after a table
** is dropped in order to keep the internal representation of the
** schema consistent with what is on disk.
*/
case OP_DropTable: {        /* no-push */
  sqlite3UnlinkAndDeleteTable(db, pOp->p1, pOp->p3);
  break;
}

/* Opcode: DropIndex P1 * P3
**
** Remove the internal (in-memory) data structures that describe
** the index named P3 in database P1.  This is called after an index
** is dropped in order to keep the internal representation of the
** schema consistent with what is on disk.
*/
case OP_DropIndex: {        /* no-push */
  sqlite3UnlinkAndDeleteIndex(db, pOp->p1, pOp->p3);
  break;
}

/* Opcode: DropTrigger P1 * P3
**
** Remove the internal (in-memory) data structures that describe
** the trigger named P3 in database P1.  This is called after a trigger
** is dropped in order to keep the internal representation of the
** schema consistent with what is on disk.
*/
case OP_DropTrigger: {        /* no-push */
  sqlite3UnlinkAndDeleteTrigger(db, pOp->p1, pOp->p3);
  break;
}


#ifndef SQLITE_OMIT_INTEGRITY_CHECK
/* Opcode: IntegrityCk * P2 *
................................................................................
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */

/* Opcode: ListWrite * * *
**
** Write the integer on the top of the stack
** into the temporary storage list.
*/
case OP_ListWrite: {        /* no-push */
  Keylist *pKeylist;
  assert( pTos>=p->aStack );
  pKeylist = p->pList;
  if( pKeylist==0 || pKeylist->nUsed>=pKeylist->nKey ){
    pKeylist = sqliteMallocRaw( sizeof(Keylist)+999*sizeof(pKeylist->aKey[0]) );
    if( pKeylist==0 ) goto no_mem;
    pKeylist->nKey = 1000;
................................................................................
  break;
}

/* Opcode: ListRewind * * *
**
** Rewind the temporary buffer back to the beginning.
*/
case OP_ListRewind: {        /* no-push */
  /* What this opcode codes, really, is reverse the order of the
  ** linked list of Keylist structures so that they are read out
  ** in the same order that they were read in. */
  Keylist *pRev, *pTop;
  pRev = 0;
  while( p->pList ){
    pTop = p->pList;
................................................................................
  break;
}

/* Opcode: ListReset * * *
**
** Reset the temporary storage buffer so that it holds nothing.
*/
case OP_ListReset: {        /* no-push */
  if( p->pList ){
    sqlite3VdbeKeylistFree(p->pList);
    p->pList = 0;
  }
  break;
}

................................................................................
#ifndef SQLITE_OMIT_SUBQUERY
/* Opcode: AggContextPush * * * 
**
** Save the state of the current aggregator. It is restored an 
** AggContextPop opcode.
** 
*/
case OP_AggContextPush: {        /* no-push */
  p->pAgg++;
  assert( p->pAgg<&p->apAgg[p->nAgg] );
  break;
}

/* Opcode: AggContextPop * * *
**
** Restore the aggregator to the state it was in when AggContextPush
** was last called. Any data in the current aggregator is deleted.
*/
case OP_AggContextPop: {        /* no-push */
  p->pAgg--;
  assert( p->pAgg>=p->apAgg );
  break;
}
#endif

#ifndef SQLITE_OMIT_TRIGGER
/* Opcode: ContextPush * * * 
**
** Save the current Vdbe context such that it can be restored by a ContextPop
** opcode. The context stores the last insert row id, the last statement change
** count, and the current statement change count.
*/
case OP_ContextPush: {        /* no-push */
  int i = p->contextStackTop++;
  Context *pContext;

  assert( i>=0 );
  /* FIX ME: This should be allocated as part of the vdbe at compile-time */
  if( i>=p->contextStackDepth ){
    p->contextStackDepth = i+1;
................................................................................

/* Opcode: ContextPop * * * 
**
** Restore the Vdbe context to the state it was in when contextPush was last
** executed. The context stores the last insert row id, the last statement
** change count, and the current statement change count.
*/
case OP_ContextPop: {        /* no-push */
  Context *pContext = &p->contextStack[--p->contextStackTop];
  assert( p->contextStackTop>=0 );
  db->lastRowid = pContext->lastRowid;
  p->nChange = pContext->nChange;
  sqlite3VdbeKeylistFree(p->pList);
  p->pList = pContext->pList;
  break;
................................................................................

/* Opcode: SortPut * * *
**
** The TOS is the key and the NOS is the data.  Pop both from the stack
** and put them on the sorter.  The key and data should have been
** made using the MakeRecord opcode.
*/
case OP_SortPut: {        /* no-push */
  Mem *pNos = &pTos[-1];
  Sorter *pSorter;
  assert( pNos>=p->aStack );
  if( Dynamicify(pTos, db->enc) ) goto no_mem;
  pSorter = sqliteMallocRaw( sizeof(Sorter) );
  if( pSorter==0 ) goto no_mem;
  pSorter->pNext = p->pSort;
................................................................................

/* Opcode: Sort * * P3
**
** Sort all elements on the sorter.  The algorithm is a
** mergesort.  The P3 argument is a pointer to a KeyInfo structure
** that describes the keys to be sorted.
*/
case OP_Sort: {        /* no-push */
  int i;
  KeyInfo *pKeyInfo = (KeyInfo*)pOp->p3;
  Sorter *pElem;
  Sorter *apSorter[NSORT];
  sqlite3_sort_count++;
  pKeyInfo->enc = p->db->enc;
  for(i=0; i<NSORT; i++){
................................................................................
  break;
}

/* Opcode: SortReset * * *
**
** Remove any elements that remain on the sorter.
*/
case OP_SortReset: {        /* no-push */
  sqlite3VdbeSorterReset(p);
  break;
}

/* Opcode: MemStore P1 P2 *
**
** Write the top of the stack into memory location P1.
................................................................................
** P1 should be a small integer since space is allocated
** for all memory locations between 0 and P1 inclusive.
**
** After the data is stored in the memory location, the
** stack is popped once if P2 is 1.  If P2 is zero, then
** the original data remains on the stack.
*/
case OP_MemStore: {        /* no-push */
  assert( pTos>=p->aStack );
  assert( pOp->p1>=0 && pOp->p1<p->nMem );
  rc = sqlite3VdbeMemMove(&p->aMem[pOp->p1], pTos);
  pTos--;

  /* If P2 is 0 then fall thru to the next opcode, OP_MemLoad, that will
  ** restore the top of the stack to its original value.
................................................................................
**
** Set the value of memory cell P1 to the maximum of its current value
** and the value on the top of the stack.  The stack is unchanged.
**
** This instruction throws an error if the memory cell is not initially
** an integer.
*/
case OP_MemMax: {        /* no-push */
  int i = pOp->p1;
  Mem *pMem;
  assert( pTos>=p->aStack );
  assert( i>=0 && i<p->nMem );
  pMem = &p->aMem[i];
  Integerify(pMem);
  Integerify(pTos);
................................................................................
** Increment the integer valued memory cell P1 by 1.  If P2 is not zero
** and the result after the increment is exactly 1, then jump
** to P2.
**
** This instruction throws an error if the memory cell is not initially
** an integer.
*/
case OP_MemIncr: {        /* no-push */
  int i = pOp->p1;
  Mem *pMem;
  assert( i>=0 && i<p->nMem );
  pMem = &p->aMem[i];
  assert( pMem->flags==MEM_Int );
  pMem->i++;
  if( pOp->p2>0 && pMem->i==1 ){
................................................................................
}

/* Opcode: IfMemPos P1 P2 *
**
** If the value of memory cell P1 is 1 or greater, jump to P2. This
** opcode assumes that memory cell P1 holds an integer value.
*/
case OP_IfMemPos: {        /* no-push */
  int i = pOp->p1;
  Mem *pMem;
  assert( i>=0 && i<p->nMem );
  pMem = &p->aMem[i];
  assert( pMem->flags==MEM_Int );
  if( pMem->i>0 ){
     pc = pOp->p2 - 1;
................................................................................
** data. Future aggregator elements will contain P2 values each and be sorted
** using the KeyInfo structure pointed to by P3.
**
** If P1 is non-zero, then only a single aggregator row is available (i.e.
** there is no GROUP BY expression). In this case it is illegal to invoke
** OP_AggFocus.
*/
case OP_AggReset: {        /* no-push */
  assert( !pOp->p3 || pOp->p3type==P3_KEYINFO );
  if( pOp->p1 ){
    rc = sqlite3VdbeAggReset(0, p->pAgg, (KeyInfo *)pOp->p3);
    p->pAgg->nMem = pOp->p2;    /* Agg.nMem is used by AggInsert() */
    rc = AggInsert(p->pAgg, 0, 0);
  }else{
    rc = sqlite3VdbeAggReset(db, p->pAgg, (KeyInfo *)pOp->p3);
................................................................................

/* Opcode: AggInit * P2 P3
**
** Initialize the function parameters for an aggregate function.
** The aggregate will operate out of aggregate column P2.
** P3 is a pointer to the FuncDef structure for the function.
*/
case OP_AggInit: {        /* no-push */
  int i = pOp->p2;
  assert( i>=0 && i<p->pAgg->nMem );
  p->pAgg->apFunc[i] = (FuncDef*)pOp->p3;
  break;
}

/* Opcode: AggFunc * P2 P3
................................................................................
** structure that specifies the function.
**
** The top of the stack must be an integer which is the index of
** the aggregate column that corresponds to this aggregate function.
** Ideally, this index would be another parameter, but there are
** no free parameters left.  The integer is popped from the stack.
*/
case OP_AggFunc: {        /* no-push */
  int n = pOp->p2;
  int i;
  Mem *pMem, *pRec;
  sqlite3_context ctx;
  sqlite3_value **apVal;

  assert( n>=0 );
................................................................................
**
** The order of aggregator opcodes is important.  The order is:
** AggReset AggFocus AggNext.  In other words, you must execute
** AggReset first, then zero or more AggFocus operations, then
** zero or more AggNext operations.  You must not execute an AggFocus
** in between an AggNext and an AggReset.
*/
case OP_AggFocus: {        /* no-push */
  char *zKey;
  int nKey;
  int res;
  assert( pTos>=p->aStack );
  Stringify(pTos, db->enc);
  zKey = pTos->z;
  nKey = pTos->n;
................................................................................
}

/* Opcode: AggSet * P2 *
**
** Move the top of the stack into the P2-th field of the current
** aggregate.  String values are duplicated into new memory.
*/
case OP_AggSet: {        /* no-push */
  AggElem *pFocus;
  int i = pOp->p2;
  pFocus = p->pAgg->pCurrent;
  assert( pTos>=p->aStack );
  if( pFocus==0 ) goto no_mem;
  assert( i>=0 && i<p->pAgg->nMem );
  rc = sqlite3VdbeMemMove(&pFocus->aMem[i], pTos);
................................................................................
**
** The order of aggregator opcodes is important.  The order is:
** AggReset AggFocus AggNext.  In other words, you must execute
** AggReset first, then zero or more AggFocus operations, then
** zero or more AggNext operations.  You must not execute an AggFocus
** in between an AggNext and an AggReset.
*/
case OP_AggNext: {        /* no-push */
  int res;
  assert( rc==SQLITE_OK );
  CHECK_FOR_INTERRUPT;
  if( p->pAgg->searching==0 ){
    p->pAgg->searching = 1;
    if( p->pAgg->pCsr ){
      rc = sqlite3BtreeFirst(p->pAgg->pCsr, &res);
................................................................................

/* Opcode: Vacuum * * *
**
** Vacuum the entire database.  This opcode will cause other virtual
** machines to be created and run.  It may not be called from within
** a transaction.
*/
case OP_Vacuum: {        /* no-push */
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse; 
  rc = sqlite3RunVacuum(&p->zErrMsg, db);
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
  break;
}

/* Opcode: Expire P1 * *
................................................................................
** Cause precompiled statements to become expired. An expired statement
** fails with an error code of SQLITE_SCHEMA if it is ever executed 
** (via sqlite3_step()).
** 
** If P1 is 0, then all SQL statements become expired. If P1 is non-zero,
** then only the currently executing statement is affected. 
*/
case OP_Expire: {        /* no-push */
  if( !pOp->p1 ){
    sqlite3ExpirePreparedStatements(db);
  }else{
    p->expired = 1;
  }
  break;
}

Changes to src/vdbeInt.h.

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int sqlite3VdbeMemIntegerify(Mem*);
double sqlite3VdbeRealValue(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
#ifndef NDEBUG
void sqlite3VdbeMemSanity(Mem*, u8);
int sqlite3VdbeOpcodeUsesStack(u8);
#endif
int sqlite3VdbeMemTranslate(Mem*, u8);
void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf, int nBuf);
int sqlite3VdbeMemHandleBom(Mem *pMem);







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int sqlite3VdbeMemIntegerify(Mem*);
double sqlite3VdbeRealValue(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
#ifndef NDEBUG
void sqlite3VdbeMemSanity(Mem*, u8);
int sqlite3VdbeOpcodeNoPush(u8);
#endif
int sqlite3VdbeMemTranslate(Mem*, u8);
void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf, int nBuf);
int sqlite3VdbeMemHandleBom(Mem *pMem);

Changes to src/vdbeaux.c.

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  }
}

/*
** Return non-zero if opcode 'op' is guarenteed not to push more values
** onto the VDBE stack than it pops off.
*/
static int opcodeUsesStack(u8 op){
  /* The 10 STACK_MASK_n constants are defined in the automatically
  ** generated header file opcodes.h. Each is a 16-bit bitmask, one
  ** bit corresponding to each opcode implemented by the virtual
  ** machine in vdbe.c. The bit is true if the word "stack" appears
  ** in a comment on the same line as the "case OP_XXX:" in 
  ** sqlite3VdbeExec() in vdbe.c.
  **
  ** If the bit is true, then the corresponding opcode is guarenteed not
  ** to grow the stack when it is executed. Otherwise, it may grow the
  ** stack by at most one entry.
  **
  ** STACK_MASK_0 corresponds to opcodes 0 to 15. STACK_MASK_1 contains
  ** one bit for opcodes 16 to 31, and so on.
  **
  ** 16-bit bitmasks (rather than 32-bit) are specified in opcodes.h 
  ** because the file is generated by an awk program. Awk manipulates
  ** all numbers as floating-point and we don't want to risk a rounding
  ** error if someone builds with an awk that uses (for example) 32-bit 
  ** IEEE floats.
  */ 
  static u32 masks[5] = {
    STACK_MASK_0 + (STACK_MASK_1<<16),
    STACK_MASK_2 + (STACK_MASK_3<<16),
    STACK_MASK_4 + (STACK_MASK_5<<16),
    STACK_MASK_6 + (STACK_MASK_7<<16),
    STACK_MASK_8 + (STACK_MASK_9<<16)
  };
  return (masks[op>>5] & (1<<(op&0x1F)));
}

#ifndef NDEBUG
int sqlite3VdbeOpcodeUsesStack(u8 op){
  return opcodeUsesStack(op);
}
#endif

/*
** Loop through the program looking for P2 values that are negative.
** Each such value is a label.  Resolve the label by setting the P2
** value to its correct non-zero value.
................................................................................
     */
    if( opcode==OP_Function ){
      if( pOp->p1>nMaxArgs ) nMaxArgs = pOp->p1;
    }else if( opcode==OP_AggFunc ){
      if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
    }

    if( opcodeUsesStack(opcode) ){
      nMaxStack--;
    }

    if( pOp->p2>=0 ) continue;
    assert( -1-pOp->p2<p->nLabel );
    pOp->p2 = aLabel[-1-pOp->p2];
  }







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  }
}

/*
** Return non-zero if opcode 'op' is guarenteed not to push more values
** onto the VDBE stack than it pops off.
*/
static int opcodeNoPush(u8 op){
  /* The 10 NOPUSH_MASK_n constants are defined in the automatically
  ** generated header file opcodes.h. Each is a 16-bit bitmask, one
  ** bit corresponding to each opcode implemented by the virtual
  ** machine in vdbe.c. The bit is true if the word "no-push" appears
  ** in a comment on the same line as the "case OP_XXX:" in 
  ** sqlite3VdbeExec() in vdbe.c.
  **
  ** If the bit is true, then the corresponding opcode is guarenteed not
  ** to grow the stack when it is executed. Otherwise, it may grow the
  ** stack by at most one entry.
  **
  ** NOPUSH_MASK_0 corresponds to opcodes 0 to 15. NOPUSH_MASK_1 contains
  ** one bit for opcodes 16 to 31, and so on.
  **
  ** 16-bit bitmasks (rather than 32-bit) are specified in opcodes.h 
  ** because the file is generated by an awk program. Awk manipulates
  ** all numbers as floating-point and we don't want to risk a rounding
  ** error if someone builds with an awk that uses (for example) 32-bit 
  ** IEEE floats.
  */ 
  static u32 masks[5] = {
    NOPUSH_MASK_0 + (NOPUSH_MASK_1<<16),
    NOPUSH_MASK_2 + (NOPUSH_MASK_3<<16),
    NOPUSH_MASK_4 + (NOPUSH_MASK_5<<16),
    NOPUSH_MASK_6 + (NOPUSH_MASK_7<<16),
    NOPUSH_MASK_8 + (NOPUSH_MASK_9<<16)
  };
  return (masks[op>>5] & (1<<(op&0x1F)));
}

#ifndef NDEBUG
int sqlite3VdbeOpcodeNoPush(u8 op){
  return opcodeNoPush(op);
}
#endif

/*
** Loop through the program looking for P2 values that are negative.
** Each such value is a label.  Resolve the label by setting the P2
** value to its correct non-zero value.
................................................................................
     */
    if( opcode==OP_Function ){
      if( pOp->p1>nMaxArgs ) nMaxArgs = pOp->p1;
    }else if( opcode==OP_AggFunc ){
      if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
    }

    if( opcodeNoPush(opcode) ){
      nMaxStack--;
    }

    if( pOp->p2>=0 ) continue;
    assert( -1-pOp->p2<p->nLabel );
    pOp->p2 = aLabel[-1-pOp->p2];
  }