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Overview
| Comment: | Prevent unnecessary rounding before multiplying |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
68dfaa349103e9111e7a53e26ebe3d07 |
| User & Date: | peterreid 2013-10-23 22:54:23 |
Context
|
2013-10-24
| ||
| 19:59 | Updates to code to read log files. check-in: aabb6dacf6 user: dan tags: trunk | |
|
2013-10-23
| ||
| 22:54 | Prevent unnecessary rounding before multiplying check-in: 68dfaa3491 user: peterreid tags: trunk | |
| 22:43 | Fix undetected multiplication overflow check-in: 2eba06d522 user: peterreid tags: trunk | |
Changes
Changes to src/math.c.
151 152 153 154 155 156 157 158 159 160 161 162 163 164 |
r.approx = 0;
return r;
}
if( A.m==0 ) return A;
if( B.m==0 ) return B;
while( A.m%10==0 ){ A.m /= 10; A.e++; }
while( B.m%10==0 ){ B.m /= 10; B.e++; }
r.sign = A.sign ^ B.sign;
r.approx = A.approx | B.approx;
while( multWillOverflow(A.m, B.m) ){
r.approx = 1;
if( A.m>B.m ){
A.m /= 10;
A.e++;
|
> > |
151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 |
r.approx = 0;
return r;
}
if( A.m==0 ) return A;
if( B.m==0 ) return B;
while( A.m%10==0 ){ A.m /= 10; A.e++; }
while( B.m%10==0 ){ B.m /= 10; B.e++; }
while( A.m%5==0 && B.m%2==0 ){ A.m /= 5; A.e++; B.m /= 2; }
while( B.m%5==0 && A.m%2==0 ){ B.m /= 5; B.e++; A.m /= 2; }
r.sign = A.sign ^ B.sign;
r.approx = A.approx | B.approx;
while( multWillOverflow(A.m, B.m) ){
r.approx = 1;
if( A.m>B.m ){
A.m /= 10;
A.e++;
|
Changes to test/num.test.
94 95 96 97 98 99 100 101 102 103 104 105 106 107 |
7 NaN 1 NaN
8 NaN -9 NaN
9 NaN NaN NaN
} {
do_test num-5.1.$tn {
sqlite4_num_to_text [sqlite4_num_mul $a $b]
} $product
}
# 5.2: Overflow that depends on the product of the two least
# significant halves
do_test num-5.2.1 {
sqlite4_num_mul 3 6148914691236517211
} {sign:0 approx:1 e:1 m:1844674407370955163}
do_test num-5.2.2 {
|
> > > > > > > > > |
94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 |
7 NaN 1 NaN
8 NaN -9 NaN
9 NaN NaN NaN
} {
do_test num-5.1.$tn {
sqlite4_num_to_text [sqlite4_num_mul $a $b]
} $product
}
foreach {tn a b product} {
1 1125899906842624 95367431640625 107374182400000000000000000000
1 95367431640625 1125899906842624 107374182400000000000000000000
2 40000000000 30000000000 1200000000000000000000
} {
do_test num-5.2.$tn {
sqlite4_num_compare [sqlite4_num_mul $a $b] $product
} {equal}
}
# 5.2: Overflow that depends on the product of the two least
# significant halves
do_test num-5.2.1 {
sqlite4_num_mul 3 6148914691236517211
} {sign:0 approx:1 e:1 m:1844674407370955163}
do_test num-5.2.2 {
|