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V0.9: Fix verinum negative comparisons. 

For mixed sized negative operands the verinum comparisons were sometimes
returning the wrong value.
This commit is contained in:
Cary R 2011-07-18 19:53:15 -07:00 committed by Stephen Williams
parent bfb1678dee
commit 0af5b0b16e
1 changed files with 32 additions and 6 deletions
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38
verinum.cc
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@ -768,7 +768,8 @@ verinum::V operator <= (const verinum&left, const verinum&right)
{ {
verinum::V left_pad = verinum::V0; verinum::V left_pad = verinum::V0;
verinum::V right_pad = verinum::V0; verinum::V right_pad = verinum::V0;
if (left.has_sign() && right.has_sign()) { bool signed_calc = left.has_sign() && right.has_sign();
if (signed_calc) {
left_pad = left.get(left.len()-1); left_pad = left.get(left.len()-1);
right_pad = right.get(right.len()-1); right_pad = right.get(right.len()-1);
@ -780,11 +781,23 @@ verinum::V operator <= (const verinum&left, const verinum&right)
unsigned idx; unsigned idx;
for (idx = left.len() ; idx > right.len() ; idx -= 1) { for (idx = left.len() ; idx > right.len() ; idx -= 1) {
if (left[idx-1] != right_pad) return verinum::V0; if (left[idx-1] != right_pad) {
// A change of padding for a negative left argument
// denotes the left value is less than the right.
return (signed_calc &&
(left_pad == verinum::V1)) ? verinum::V1 :
verinum::V0;
}
} }
for (idx = right.len() ; idx > left.len() ; idx -= 1) { for (idx = right.len() ; idx > left.len() ; idx -= 1) {
if (right[idx-1] != left_pad) return verinum::V1; if (right[idx-1] != left_pad) {
// A change of padding for a negative right argument
// denotes the left value is not less than the right.
return (signed_calc &&
(right_pad == verinum::V1)) ? verinum::V0 :
verinum::V1;
}
} }
idx = right.len(); idx = right.len();
@ -807,7 +820,8 @@ verinum::V operator < (const verinum&left, const verinum&right)
{ {
verinum::V left_pad = verinum::V0; verinum::V left_pad = verinum::V0;
verinum::V right_pad = verinum::V0; verinum::V right_pad = verinum::V0;
if (left.has_sign() && right.has_sign()) { bool signed_calc = left.has_sign() && right.has_sign();
if (signed_calc) {
left_pad = left.get(left.len()-1); left_pad = left.get(left.len()-1);
right_pad = right.get(right.len()-1); right_pad = right.get(right.len()-1);
@ -819,11 +833,23 @@ verinum::V operator < (const verinum&left, const verinum&right)
unsigned idx; unsigned idx;
for (idx = left.len() ; idx > right.len() ; idx -= 1) { for (idx = left.len() ; idx > right.len() ; idx -= 1) {
if (left[idx-1] != right_pad) return verinum::V0; if (left[idx-1] != right_pad) {
// A change of padding for a negative left argument
// denotes the left value is less than the right.
return (signed_calc &&
(left_pad == verinum::V1)) ? verinum::V1 :
verinum::V0;
}
} }
for (idx = right.len() ; idx > left.len() ; idx -= 1) { for (idx = right.len() ; idx > left.len() ; idx -= 1) {
if (right[idx-1] != left_pad) return verinum::V1; if (right[idx-1] != left_pad) {
// A change of padding for a negative right argument
// denotes the left value is not less than the right.
return (signed_calc &&
(right_pad == verinum::V1)) ? verinum::V0 :
verinum::V1;
}
} }
while (idx > 0) { while (idx > 0) {