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]
  }

}

    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]
  }
}

**
** 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;
}

**
** 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;
}

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);

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);

  }
}

/*
** 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];
  }

  }
}

/*
** 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];
  }