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UserspaceEmulator: The generic_RM*_imm8 functions need to sign extend

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We are supposed to sign-extend the 8-bit immediate here,
"cmp eax, 0xff" is actually "cmp eax, 0xffffffff"
This commit is contained in:
Andreas Kling 2020-07-11 23:19:31 +02:00
parent 21837544bb
commit 6febad1ef3
1 changed files with 12 additions and 4 deletions
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16
DevTools/UserspaceEmulator/SoftCPU.cpp
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@ -32,6 +32,14 @@
namespace UserspaceEmulator {
template<typename T, typename U>
inline constexpr T sign_extended_to(U value)
{
if (!(value & X86::TypeTrivia<U>::sign_bit))
return value;
return (X86::TypeTrivia<T>::mask & ~X86::TypeTrivia<U>::mask) | value;
}
template<typename T>
struct TypeDoubler {
};
@ -443,7 +451,7 @@ template<bool update_dest, typename Op>
void SoftCPU::generic_RM16_imm8(Op op, const X86::Instruction& insn)
{
auto dest = insn.modrm().read16(*this, insn);
auto src = insn.imm8();
auto src = sign_extended_to<u16>(insn.imm8());
auto result = op(*this, dest, src);
if (update_dest)
insn.modrm().write16(*this, insn, result);
@ -473,7 +481,7 @@ template<bool update_dest, typename Op>
void SoftCPU::generic_RM32_imm8(Op op, const X86::Instruction& insn)
{
auto dest = insn.modrm().read32(*this, insn);
auto src = insn.imm8();
auto src = sign_extended_to<u32>(insn.imm8());
auto result = op(*this, dest, src);
if (update_dest)
insn.modrm().write32(*this, insn, result);
@ -1307,8 +1315,8 @@ void SoftCPU::XLAT(const X86::Instruction&) { TODO(); }
#define DEFINE_GENERIC_INSN_HANDLERS(mnemonic, op, update_dest) \
DEFINE_GENERIC_INSN_HANDLERS_PARTIAL(mnemonic, op, update_dest) \
void SoftCPU::mnemonic##_RM16_imm8(const X86::Instruction& insn) { generic_RM16_imm8<update_dest>(op<u16, u8>, insn); } \
void SoftCPU::mnemonic##_RM32_imm8(const X86::Instruction& insn) { generic_RM32_imm8<update_dest>(op<u32, u8>, insn); } \
void SoftCPU::mnemonic##_RM16_imm8(const X86::Instruction& insn) { generic_RM16_imm8<update_dest>(op<u16, u16>, insn); } \
void SoftCPU::mnemonic##_RM32_imm8(const X86::Instruction& insn) { generic_RM32_imm8<update_dest>(op<u32, u32>, insn); } \
void SoftCPU::mnemonic##_reg16_RM16(const X86::Instruction& insn) { generic_reg16_RM16<update_dest>(op<u16, u16>, insn); } \
void SoftCPU::mnemonic##_reg32_RM32(const X86::Instruction& insn) { generic_reg32_RM32<update_dest>(op<u32, u32>, insn); } \
void SoftCPU::mnemonic##_reg8_RM8(const X86::Instruction& insn) { generic_reg8_RM8<update_dest>(op<u8, u8>, insn); }