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cxxrtl: Extract divmod algorithm into value

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Merry 2023-12-09 14:37:53 +00:00 • committed by Catherine
parent 99c8143ded
commit 0681baae19
1 changed files with 42 additions and 23 deletions
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65
backends/cxxrtl/runtime/cxxrtl/cxxrtl.h
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@ -576,6 +576,37 @@ struct value : public expr_base<value<Bits>> {
result.data[result.chunks - 1] &= result.msb_mask;
return result;
}
std::pair<value<Bits>, value<Bits>> udivmod(value<Bits> divisor) const {
value<Bits> quotient;
value<Bits> dividend = *this;
if (dividend.ucmp(divisor))
return {/*quotient=*/value<Bits>{0u}, /*remainder=*/dividend};
uint32_t divisor_shift = dividend.ctlz() - divisor.ctlz();
divisor = divisor.shl(value<Bits>{divisor_shift});
for (size_t step = 0; step <= divisor_shift; step++) {
quotient = quotient.shl(value<Bits>{1u});
if (!dividend.ucmp(divisor)) {
dividend = dividend.sub(divisor);
quotient.set_bit(0, true);
}
divisor = divisor.shr(value<Bits>{1u});
}
return {quotient, /*remainder=*/dividend};
}
std::pair<value<Bits>, value<Bits>> sdivmod(const value<Bits> &other) const {
value<Bits + 1> quotient;
value<Bits + 1> remainder;
value<Bits + 1> dividend = sext<Bits + 1>();
value<Bits + 1> divisor = other.template sext<Bits + 1>();
if (dividend.is_neg()) dividend = dividend.neg();
if (divisor.is_neg()) divisor = divisor.neg();
std::tie(quotient, remainder) = dividend.udivmod(divisor);
if (dividend.is_neg() != divisor.is_neg()) quotient = quotient.neg();
if (dividend.is_neg()) remainder = remainder.neg();
return {quotient.template trunc<Bits>(), remainder.template trunc<Bits>()};
}
};
// Expression template for a slice, usable as lvalue or rvalue, and composable with other expression templates here.
@ -764,7 +795,7 @@ std::ostream &operator<<(std::ostream &os, const value_formatted<Bits> &vf)
buf += '0';
while (!val.is_zero()) {
value<Bits> quotient, remainder;
std::tie(quotient, remainder) = val.template divmod_uu<Bits>(value<Bits>{10u});
std::tie(quotient, remainder) = val.udivmod(value<Bits>{10u});
buf += '0' + remainder.template trunc<(Bits > 4 ? 4 : Bits)>().val().template get<uint8_t>();
val = quotient;
}
@ -1649,35 +1680,23 @@ CXXRTL_ALWAYS_INLINE
std::pair<value<BitsY>, value<BitsY>> divmod_uu(const value<BitsA> &a, const value<BitsB> &b) {
constexpr size_t Bits = max(BitsY, max(BitsA, BitsB));
value<Bits> quotient;
value<Bits> remainder;
value<Bits> dividend = a.template zext<Bits>();
value<Bits> divisor = b.template zext<Bits>();
if (dividend.ucmp(divisor))
return {/*quotient=*/value<BitsY> { 0u }, /*remainder=*/dividend.template trunc<BitsY>()};
uint32_t divisor_shift = dividend.ctlz() - divisor.ctlz();
divisor = divisor.shl(value<32> { divisor_shift });
for (size_t step = 0; step <= divisor_shift; step++) {
quotient = quotient.shl(value<1> { 1u });
if (!dividend.ucmp(divisor)) {
dividend = dividend.sub(divisor);
quotient.set_bit(0, true);
}
divisor = divisor.shr(value<1> { 1u });
}
return {quotient.template trunc<BitsY>(), /*remainder=*/dividend.template trunc<BitsY>()};
std::tie(quotient, remainder) = dividend.udivmod(divisor);
return {quotient.template trunc<BitsY>(), remainder.template trunc<BitsY>()};
}
template<size_t BitsY, size_t BitsA, size_t BitsB>
CXXRTL_ALWAYS_INLINE
std::pair<value<BitsY>, value<BitsY>> divmod_ss(const value<BitsA> &a, const value<BitsB> &b) {
value<BitsA + 1> ua = a.template sext<BitsA + 1>();
value<BitsB + 1> ub = b.template sext<BitsB + 1>();
if (ua.is_neg()) ua = ua.neg();
if (ub.is_neg()) ub = ub.neg();
value<BitsY> y, r;
std::tie(y, r) = divmod_uu<BitsY>(ua, ub);
if (a.is_neg() != b.is_neg()) y = y.neg();
if (a.is_neg()) r = r.neg();
return {y, r};
constexpr size_t Bits = max(BitsY, max(BitsA, BitsB));
value<Bits> quotient;
value<Bits> remainder;
value<Bits> dividend = a.template sext<Bits>();
value<Bits> divisor = b.template sext<Bits>();
std::tie(quotient, remainder) = dividend.sdivmod(divisor);
return {quotient.template trunc<BitsY>(), remainder.template trunc<BitsY>()};
}
template<size_t BitsY, size_t BitsA, size_t BitsB>