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Merge pull request #1020 from TomHarte/RotateMask

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Improve PowerPC rotate mask generation.
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Thomas Harte 2022-04-10 15:24:17 -04:00 committed by GitHub
commit 945e935312
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1 changed files with 4 additions and 3 deletions
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7
InstructionSets/PowerPC/Instruction.hpp
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@ -1451,12 +1451,13 @@ struct Instruction {
/// mb < me+1 => set [mb, me]
/// mb == me+1 => set all bits
/// mb > me+1 => complement of set [me+1, mb-1]
uint32_t rotate_mask() const {
template <typename IntT> IntT rotate_mask() const {
const auto mb_bit = mb();
const auto me_bit = me();
uint32_t result = (0xffff'ffff >> mb_bit) ^ (0x7fff'ffff >> me_bit);
return result ^ ((mb_bit < me_bit+1) ? 0 : 0xffff'ffff);
const IntT result = (0xffff'ffff >> mb_bit) ^ (0x7fff'ffff >> me_bit);
const IntT sign = ~IntT((int32_t(mb_bit) - int32_t(me_bit+1)) >> 16);
return result ^ sign;
}
/// Condition register source bit A.