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cxxrtl: Fix `ctlz` implementation

This commit is contained in:
Martin Povišer 2023-12-11 22:10:51 +01:00
parent cca12d9d9b
commit bcf5e92389
1 changed files with 6 additions and 5 deletions
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11
backends/cxxrtl/runtime/cxxrtl/cxxrtl.h
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@ -508,12 +508,13 @@ struct value : public expr_base<value<Bits>> {
size_t count = 0; size_t count = 0;
for (size_t n = 0; n < chunks; n++) { for (size_t n = 0; n < chunks; n++) {
chunk::type x = data[chunks - 1 - n]; chunk::type x = data[chunks - 1 - n];
if (x == 0) { // First add to `count` as if the chunk is zero
count += (n == 0 ? Bits % chunk::bits : chunk::bits); count += (n == 0 ? Bits % chunk::bits : chunk::bits);
} else { // If the chunk isn't zero, correct the `count` value and return
// This loop implements the find first set idiom as recognized by LLVM. if (x != 0) {
for (; x != 0; count++) for (; x != 0; count--)
x >>= 1; x >>= 1;
break;
} }
} }
return count; return count;