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Overview
| Comment: | Faster implementation for sqlite3MulInt64(). |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
010c48f671e909cb406f3716102a0032 |
| User & Date: | drh 2014-02-10 12:59:15 |
Context
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2014-02-10
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| 15:56 | Improvements to a "Synopsis:" comment in the VDBE engine. check-in: 0dfa7ee9 user: drh tags: trunk | |
| 12:59 | Faster implementation for sqlite3MulInt64(). check-in: 010c48f6 user: drh tags: trunk | |
| 03:21 | Faster and smaller implementation of sqlite3_value_type(). check-in: 5708bc24 user: drh tags: trunk | |
Changes
Changes to src/util.c.
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i64 iA = *pA;
testcase( iA==0 ); testcase( iA==1 );
testcase( iB==-1 ); testcase( iB==0 );
if( iB>=0 ){
testcase( iA>0 && LARGEST_INT64 - iA == iB );
testcase( iA>0 && LARGEST_INT64 - iA == iB - 1 );
if( iA>0 && LARGEST_INT64 - iA < iB ) return 1;
*pA += iB;
}else{
testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 1 );
testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 2 );
if( iA<0 && -(iA + LARGEST_INT64) > iB + 1 ) return 1;
*pA += iB;
}
return 0;
}
int sqlite3SubInt64(i64 *pA, i64 iB){
testcase( iB==SMALLEST_INT64+1 );
if( iB==SMALLEST_INT64 ){
testcase( (*pA)==(-1) ); testcase( (*pA)==0 );
if( (*pA)>=0 ) return 1;
................................................................................
i64 iA = *pA;
i64 iA1, iA0, iB1, iB0, r;
iA1 = iA/TWOPOWER32;
iA0 = iA % TWOPOWER32;
iB1 = iB/TWOPOWER32;
iB0 = iB % TWOPOWER32;
if( iA1*iB1 != 0 ) return 1;
assert( iA1*iB0==0 || iA0*iB1==0 );
r = iA1*iB0 + iA0*iB1;
testcase( r==(-TWOPOWER31)-1 );
testcase( r==(-TWOPOWER31) );
testcase( r==TWOPOWER31 );
testcase( r==TWOPOWER31-1 );
if( r<(-TWOPOWER31) || r>=TWOPOWER31 ) return 1;
r *= TWOPOWER32;
if( sqlite3AddInt64(&r, iA0*iB0) ) return 1;
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i64 iA = *pA;
testcase( iA==0 ); testcase( iA==1 );
testcase( iB==-1 ); testcase( iB==0 );
if( iB>=0 ){
testcase( iA>0 && LARGEST_INT64 - iA == iB );
testcase( iA>0 && LARGEST_INT64 - iA == iB - 1 );
if( iA>0 && LARGEST_INT64 - iA < iB ) return 1;
}else{
testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 1 );
testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 2 );
if( iA<0 && -(iA + LARGEST_INT64) > iB + 1 ) return 1;
}
*pA += iB;
return 0;
}
int sqlite3SubInt64(i64 *pA, i64 iB){
testcase( iB==SMALLEST_INT64+1 );
if( iB==SMALLEST_INT64 ){
testcase( (*pA)==(-1) ); testcase( (*pA)==0 );
if( (*pA)>=0 ) return 1;
................................................................................
i64 iA = *pA;
i64 iA1, iA0, iB1, iB0, r;
iA1 = iA/TWOPOWER32;
iA0 = iA % TWOPOWER32;
iB1 = iB/TWOPOWER32;
iB0 = iB % TWOPOWER32;
if( iA1==0 ){
if( iB1==0 ){
*pA *= iB;
return 0;
}
r = iA0*iB1;
}else if( iB1==0 ){
r = iA1*iB0;
}else{
/* If both iA1 and iB1 are non-zero, overflow will result */
return 1;
}
testcase( r==(-TWOPOWER31)-1 );
testcase( r==(-TWOPOWER31) );
testcase( r==TWOPOWER31 );
testcase( r==TWOPOWER31-1 );
if( r<(-TWOPOWER31) || r>=TWOPOWER31 ) return 1;
r *= TWOPOWER32;
if( sqlite3AddInt64(&r, iA0*iB0) ) return 1;
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