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Refactor some jump opcodes in the VDBE. Add JumpZeroIncr and DecrJumpZero.

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Fix the LIKE optimization to work with DESC sort order.

FossilOrigin-Name: 26cb5145bf52f8c3fffa8c69b6c24aee4d974883
This commit is contained in:
drh
2015-03-07 00:57:37 +00:00
parent a9c18a9067
commit 16897072b5
7 changed files with 100 additions and 38 deletions
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56
src/vdbe.c
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@@ -5585,10 +5585,12 @@ case OP_MemMax: { /* in2 */
/* Opcode: IfPos P1 P2 * * *
** Synopsis: if r[P1]>0 goto P2
**
** If the value of register P1 is 1 or greater, jump to P2.
** Register P1 must contain an integer.
** If the value of register P1 is 1 or greater, jump to P2 and
** add the literal value P3 to register P1.
**
** It is illegal to use this instruction on a register that does
** not contain an integer. An assertion fault will result if you try.
** If the initial value of register P1 is less than 1, then the
** value is unchanged and control passes through to the next instruction.
*/
case OP_IfPos: { /* jump, in1 */
pIn1 = &aMem[pOp->p1];
@@ -5617,16 +5619,34 @@ case OP_IfNeg: { /* jump, in1 */
break;
}
/* Opcode: IfZero P1 P2 P3 * *
** Synopsis: r[P1]+=P3, if r[P1]==0 goto P2
/* Opcode: IfNotZero P1 P2 P3 * *
** Synopsis: if r[P1]!=0 then r[P1]+=P3, goto P2
**
** The register P1 must contain an integer. Add literal P3 to the
** value in register P1. If the result is exactly 0, jump to P2.
** Register P1 must contain an integer. If the content of register P1 is
** initially nonzero, then add P3 to P1 and jump to P2. If register P1 is
** initially zero, leave it unchanged and fall through.
*/
case OP_IfZero: { /* jump, in1 */
case OP_IfNotZero: { /* jump, in1 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags&MEM_Int );
pIn1->u.i += pOp->p3;
VdbeBranchTaken(pIn1->u.i<0, 2);
if( pIn1->u.i ){
pIn1->u.i += pOp->p3;
pc = pOp->p2 - 1;
}
break;
}
/* Opcode: DecrJumpZero P1 P2 * * *
** Synopsis: if (--r[P1])==0 goto P2
**
** Register P1 must hold an integer. Decrement the value in register P1
** then jump to P2 if the new value is exactly zero.
*/
case OP_DecrJumpZero: { /* jump, in1 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags&MEM_Int );
pIn1->u.i--;
VdbeBranchTaken(pIn1->u.i==0, 2);
if( pIn1->u.i==0 ){
pc = pOp->p2 - 1;
@@ -5634,6 +5654,24 @@ case OP_IfZero: { /* jump, in1 */
break;
}
/* Opcode: JumpZeroIncr P1 P2 * * *
** Synopsis: if (r[P1]++)==0 ) goto P2
**
** The register P1 must contain an integer. If register P1 is initially
** zero, then jump to P2. Increment register P1 regardless of whether or
** not the jump is taken.
*/
case OP_JumpZeroIncr: { /* jump, in1 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags&MEM_Int );
VdbeBranchTaken(pIn1->u.i==0, 2);
if( (pIn1->u.i++)==0 ){
pc = pOp->p2 - 1;
}
break;
}
/* Opcode: AggStep * P2 P3 P4 P5
** Synopsis: accum=r[P3] step(r[P2@P5])
**