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Overview
| Comment: | Change the OP_IfNotZero opcode so that it decrements register P1 by 1 rather than the value in P3, and so that it only decrements if originally positive. This avoids decrementing the smallest 64-bit signed integer. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
165c044686212fbf7182dd560ad1e57e |
| User & Date: | drh 2016-12-18 17:42:00 |
Context
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2016-12-21
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| 19:45 | Simplifications to the way UnpackedRecord objects are allocated. Smaller and faster code that also fixes a subtle (currently unreachable) bug. check-in: f7ab01f2 user: drh tags: trunk | |
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2016-12-18
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| 17:42 | Change the OP_IfNotZero opcode so that it decrements register P1 by 1 rather than the value in P3, and so that it only decrements if originally positive. This avoids decrementing the smallest 64-bit signed integer. check-in: 165c0446 user: drh tags: trunk | |
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2016-12-17
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| 21:07 | Refinements to the new dbfuzz test program. check-in: 50325abe user: drh tags: trunk | |
Changes
Changes to src/select.c.
592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 |
if( iLimit ){
int addr;
int r1 = 0;
/* Fill the sorter until it contains LIMIT+OFFSET entries. (The iLimit
** register is initialized with value of LIMIT+OFFSET.) After the sorter
** fills up, delete the least entry in the sorter after each insert.
** Thus we never hold more than the LIMIT+OFFSET rows in memory at once */
addr = sqlite3VdbeAddOp3(v, OP_IfNotZero, iLimit, 0, 1); VdbeCoverage(v);
sqlite3VdbeAddOp1(v, OP_Last, pSort->iECursor);
if( pSort->bOrderedInnerLoop ){
r1 = ++pParse->nMem;
sqlite3VdbeAddOp3(v, OP_Column, pSort->iECursor, nExpr, r1);
VdbeComment((v, "seq"));
}
sqlite3VdbeAddOp1(v, OP_Delete, pSort->iECursor);
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592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 |
if( iLimit ){
int addr;
int r1 = 0;
/* Fill the sorter until it contains LIMIT+OFFSET entries. (The iLimit
** register is initialized with value of LIMIT+OFFSET.) After the sorter
** fills up, delete the least entry in the sorter after each insert.
** Thus we never hold more than the LIMIT+OFFSET rows in memory at once */
addr = sqlite3VdbeAddOp1(v, OP_IfNotZero, iLimit); VdbeCoverage(v);
sqlite3VdbeAddOp1(v, OP_Last, pSort->iECursor);
if( pSort->bOrderedInnerLoop ){
r1 = ++pParse->nMem;
sqlite3VdbeAddOp3(v, OP_Column, pSort->iECursor, nExpr, r1);
VdbeComment((v, "seq"));
}
sqlite3VdbeAddOp1(v, OP_Delete, pSort->iECursor);
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Changes to src/vdbe.c.
6008 6009 6010 6011 6012 6013 6014 6015 6016 6017 6018 6019 6020 6021 6022 6023 6024 6025 6026 6027 6028 6029 6030 6031 6032 6033 6034 6035 |
pOut->u.i = -1;
}else{
pOut->u.i = x;
}
break;
}
/* Opcode: IfNotZero P1 P2 P3 * *
** Synopsis: if r[P1]!=0 then r[P1]-=P3, goto P2
**
** Register P1 must contain an integer. If the content of register P1 is
** initially nonzero, then subtract P3 from the value in register P1 and
** jump to P2. If register P1 is initially zero, leave it unchanged
** and fall through.
*/
case OP_IfNotZero: { /* jump, in1 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags&MEM_Int );
VdbeBranchTaken(pIn1->u.i<0, 2);
if( pIn1->u.i ){
pIn1->u.i -= pOp->p3;
goto jump_to_p2;
}
break;
}
/* Opcode: DecrJumpZero P1 P2 * * *
** Synopsis: if (--r[P1])==0 goto P2
|
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6008 6009 6010 6011 6012 6013 6014 6015 6016 6017 6018 6019 6020 6021 6022 6023 6024 6025 6026 6027 6028 6029 6030 6031 6032 6033 6034 6035 |
pOut->u.i = -1;
}else{
pOut->u.i = x;
}
break;
}
/* Opcode: IfNotZero P1 P2 * * *
** Synopsis: if r[P1]!=0 then r[P1]--, goto P2
**
** Register P1 must contain an integer. If the content of register P1 is
** initially greater than zero, then decrement the value in register P1.
** If it is non-zero (negative or positive) and then also jump to P2.
** If register P1 is initially zero, leave it unchanged and fall through.
*/
case OP_IfNotZero: { /* jump, in1 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags&MEM_Int );
VdbeBranchTaken(pIn1->u.i<0, 2);
if( pIn1->u.i ){
if( pIn1->u.i>0 ) pIn1->u.i--;
goto jump_to_p2;
}
break;
}
/* Opcode: DecrJumpZero P1 P2 * * *
** Synopsis: if (--r[P1])==0 goto P2
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