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Overview
Comment:Break up the implementation of OP_Move, OP_Copy, and OP_SCopy to reduce the number of branch instructions. (CVS 4945)
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SHA1:53e533d3a764d1973c24bffaacc505ea4b61a2b9
User & Date: drh 2008-04-01 00:36:10
Context
2008-04-01
01:42
Initial test cases and bug fixes in the CSE logic. (CVS 4946) check-in: e5aff09a user: drh tags: trunk
00:36
Break up the implementation of OP_Move, OP_Copy, and OP_SCopy to reduce the number of branch instructions. (CVS 4945) check-in: 53e533d3 user: drh tags: trunk
2008-03-31
23:51
Add the veryquick.test script for a very fast overview test that omits all i/o and malloc testing. (CVS 4944) check-in: f61df8da user: drh tags: trunk
Changes
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Changes to src/vdbe.c.

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**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.723 2008/03/31 18:19:54 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................

/* Opcode: Move P1 P2 * * *
**
** Move the value in register P1 over into register P2.  Register P1
** is left holding a NULL.  It is an error for P1 and P2 to be the
** same register.
*/


















/* Opcode: Copy P1 P2 * * *
**
** Make a copy of register P1 into register P2.
**
** This instruction makes a deep copy of the value.  A duplicate
** is made of any string or blob constant.  See also OP_SCopy.
*/















/* Opcode: SCopy P1 P2 * * *
**
** Make a shallow copy of register P1 into register P2.
**
** This instruction makes a shallow copy of the value.  If the value
** is a string or blob, then the copy is only a pointer to the
** original and hence if the original changes so will the copy.
** Worse, if the original is deallocated, the copy becomes invalid.
** Thus the program must guarantee that the original will not change
** during the lifetime of the copy.  Use OP_Copy to make a complete
** copy.
*/
case OP_Move:
case OP_Copy:
case OP_SCopy: {
  assert( pOp->p1>0 );
  assert( pOp->p1<=p->nMem );
  pIn1 = &p->aMem[pOp->p1];
  REGISTER_TRACE(pOp->p1, pIn1);
  assert( pOp->p2>0 );
  assert( pOp->p2<=p->nMem );
  pOut = &p->aMem[pOp->p2];
  assert( pOut!=pIn1 );
  if( pOp->opcode==OP_Move ){
    char *zMalloc = pOut->zMalloc;
    pOut->zMalloc = 0;
    sqlite3VdbeMemMove(pOut, pIn1);
    pIn1->zMalloc = zMalloc;
  }else{
    sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
    if( pOp->opcode==OP_Copy ){
      Deephemeralize(pOut);
    }
  }
  REGISTER_TRACE(pOp->p2, pOut);
  break;
}

/* Opcode: ResultRow P1 P2 * * *
**
** The registers P1 throught P1+P2-1 contain a single row of







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**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.724 2008/04/01 00:36:10 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................

/* Opcode: Move P1 P2 * * *
**
** Move the value in register P1 over into register P2.  Register P1
** is left holding a NULL.  It is an error for P1 and P2 to be the
** same register.
*/
case OP_Move: {
  char *zMalloc;
  assert( pOp->p1>0 );
  assert( pOp->p1<=p->nMem );
  pIn1 = &p->aMem[pOp->p1];
  REGISTER_TRACE(pOp->p1, pIn1);
  assert( pOp->p2>0 );
  assert( pOp->p2<=p->nMem );
  pOut = &p->aMem[pOp->p2];
  assert( pOut!=pIn1 );
  zMalloc = pOut->zMalloc;
  pOut->zMalloc = 0;
  sqlite3VdbeMemMove(pOut, pIn1);
  pIn1->zMalloc = zMalloc;
  REGISTER_TRACE(pOp->p2, pOut);
  break;
}

/* Opcode: Copy P1 P2 * * *
**
** Make a copy of register P1 into register P2.
**
** This instruction makes a deep copy of the value.  A duplicate
** is made of any string or blob constant.  See also OP_SCopy.
*/
case OP_Copy: {
  assert( pOp->p1>0 );
  assert( pOp->p1<=p->nMem );
  pIn1 = &p->aMem[pOp->p1];
  REGISTER_TRACE(pOp->p1, pIn1);
  assert( pOp->p2>0 );
  assert( pOp->p2<=p->nMem );
  pOut = &p->aMem[pOp->p2];
  assert( pOut!=pIn1 );
  sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
  Deephemeralize(pOut);
  REGISTER_TRACE(pOp->p2, pOut);
  break;
}

/* Opcode: SCopy P1 P2 * * *
**
** Make a shallow copy of register P1 into register P2.
**
** This instruction makes a shallow copy of the value.  If the value
** is a string or blob, then the copy is only a pointer to the
** original and hence if the original changes so will the copy.
** Worse, if the original is deallocated, the copy becomes invalid.
** Thus the program must guarantee that the original will not change
** during the lifetime of the copy.  Use OP_Copy to make a complete
** copy.
*/


case OP_SCopy: {
  assert( pOp->p1>0 );
  assert( pOp->p1<=p->nMem );
  pIn1 = &p->aMem[pOp->p1];
  REGISTER_TRACE(pOp->p1, pIn1);
  assert( pOp->p2>0 );
  assert( pOp->p2<=p->nMem );
  pOut = &p->aMem[pOp->p2];
  assert( pOut!=pIn1 );






  sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);




  REGISTER_TRACE(pOp->p2, pOut);
  break;
}

/* Opcode: ResultRow P1 P2 * * *
**
** The registers P1 throught P1+P2-1 contain a single row of