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Give the decoder responsibility for sanity-checking repetitions.

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This may avoid some spurious extension words.
This commit is contained in:
Thomas Harte 2023-09-26 17:29:20 -04:00
parent cd072e1b57
commit b03b408984
3 changed files with 93 additions and 61 deletions
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124
InstructionSets/x86/Decoder.cpp
View File

@ -31,11 +31,16 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
// MARK: - Prefixes (if present) and the opcode.
/// Sets the operation and verifies that the current repetition, if any, is compatible, discarding it otherwise.
#define SetOperation(op) \
operation_ = op; \
repetition_ = supports(op, repetition_) ? repetition_ : Repetition::None
/// Helper macro for those that follow.
#define SetOpSrcDestSize(op, src, dest, size) \
operation_ = Operation::op; \
source_ = Source::src; \
destination_ = Source::dest; \
SetOperation(Operation::op); \
source_ = Source::src; \
destination_ = Source::dest; \
operation_size_ = size
/// Covers anything which is complete as soon as the opcode is encountered.
@ -65,7 +70,7 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
/// Covers both `mem/reg, reg` and `reg, mem/reg`.
#define MemRegReg(op, format, size) \
operation_ = Operation::op; \
SetOperation(Operation::op); \
phase_ = Phase::ModRegRM; \
modregrm_format_ = ModRegRMFormat::format; \
operand_size_ = DataSize::None; \
@ -73,27 +78,27 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
/// Handles JO, JNO, JB, etc — anything with only a displacement.
#define Displacement(op, size) \
operation_ = Operation::op; \
SetOperation(Operation::op); \
phase_ = Phase::DisplacementOrOperand; \
displacement_size_ = size
/// Handles PUSH [immediate], etc — anything with only an immediate operand.
#define Immediate(op, size) \
operation_ = Operation::op; \
SetOperation(Operation::op); \
source_ = Source::Immediate; \
phase_ = Phase::DisplacementOrOperand; \
operand_size_ = size
/// Handles far CALL and far JMP — fixed four or six byte operand operations.
#define Far(op) \
operation_ = Operation::op; \
SetOperation(Operation::op); \
phase_ = Phase::DisplacementOrOperand; \
operand_size_ = DataSize::Word; \
displacement_size_ = data_size(default_address_size_)
/// Handles ENTER — a fixed three-byte operation.
#define Displacement16Operand8(op) \
operation_ = Operation::op; \
SetOperation(Operation::op); \
phase_ = Phase::DisplacementOrOperand; \
displacement_size_ = DataSize::Word; \
operand_size_ = DataSize::Byte
@ -702,13 +707,13 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
switch(reg) {
default: undefined();
case 0: operation_ = Operation::TEST; break;
case 2: operation_ = Operation::NOT; break;
case 3: operation_ = Operation::NEG; break;
case 4: operation_ = Operation::MUL; break;
case 5: operation_ = Operation::IMUL_1; break;
case 6: operation_ = Operation::DIV; break;
case 7: operation_ = Operation::IDIV; break;
case 0: SetOperation(Operation::TEST); break;
case 2: SetOperation(Operation::NOT); break;
case 3: SetOperation(Operation::NEG); break;
case 4: SetOperation(Operation::MUL); break;
case 5: SetOperation(Operation::IMUL_1); break;
case 6: SetOperation(Operation::DIV); break;
case 7: SetOperation(Operation::IDIV); break;
}
break;
@ -744,13 +749,13 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
switch(reg) {
default: undefined();
case 0: operation_ = Operation::ROL; break;
case 1: operation_ = Operation::ROR; break;
case 2: operation_ = Operation::RCL; break;
case 3: operation_ = Operation::RCR; break;
case 4: operation_ = Operation::SAL; break;
case 5: operation_ = Operation::SHR; break;
case 7: operation_ = Operation::SAR; break;
case 0: SetOperation(Operation::ROL); break;
case 1: SetOperation(Operation::ROR); break;
case 2: SetOperation(Operation::RCL); break;
case 3: SetOperation(Operation::RCR); break;
case 4: SetOperation(Operation::SAL); break;
case 5: SetOperation(Operation::SHR); break;
case 7: SetOperation(Operation::SAR); break;
}
break;
@ -760,8 +765,8 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
switch(reg) {
default: undefined();
case 0: operation_ = Operation::INC; break;
case 1: operation_ = Operation::DEC; break;
case 0: SetOperation(Operation::INC); break;
case 1: SetOperation(Operation::DEC); break;
}
break;
@ -771,13 +776,13 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
switch(reg) {
default: undefined();
case 0: operation_ = Operation::INC; break;
case 1: operation_ = Operation::DEC; break;
case 2: operation_ = Operation::CALLabs; break;
case 3: operation_ = Operation::CALLfar; break;
case 4: operation_ = Operation::JMPabs; break;
case 5: operation_ = Operation::JMPfar; break;
case 6: operation_ = Operation::PUSH; break;
case 0: SetOperation(Operation::INC); break;
case 1: SetOperation(Operation::DEC); break;
case 2: SetOperation(Operation::CALLabs); break;
case 3: SetOperation(Operation::CALLfar); break;
case 4: SetOperation(Operation::JMPabs); break;
case 5: SetOperation(Operation::JMPfar); break;
case 6: SetOperation(Operation::PUSH); break;
}
// TODO: CALLfar and JMPfar aren't correct above; find out what is.
break;
@ -804,14 +809,14 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
sign_extend_operand_ = true; // Will be effective only if modregrm_format_ == ModRegRMFormat::MemRegADD_to_CMP_SignExtend.
switch(reg) {
default: operation_ = Operation::ADD; break;
case 1: operation_ = Operation::OR; break;
case 2: operation_ = Operation::ADC; break;
case 3: operation_ = Operation::SBB; break;
case 4: operation_ = Operation::AND; break;
case 5: operation_ = Operation::SUB; break;
case 6: operation_ = Operation::XOR; break;
case 7: operation_ = Operation::CMP; break;
default: SetOperation(Operation::ADD); break;
case 1: SetOperation(Operation::OR); break;
case 2: SetOperation(Operation::ADC); break;
case 3: SetOperation(Operation::SBB); break;
case 4: SetOperation(Operation::AND); break;
case 5: SetOperation(Operation::SUB); break;
case 6: SetOperation(Operation::XOR); break;
case 7: SetOperation(Operation::CMP); break;
}
break;
@ -821,12 +826,12 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
switch(reg) {
default: undefined();
case 0: operation_ = Operation::SLDT; break;
case 1: operation_ = Operation::STR; break;
case 2: operation_ = Operation::LLDT; break;
case 3: operation_ = Operation::LTR; break;
case 4: operation_ = Operation::VERR; break;
case 5: operation_ = Operation::VERW; break;
case 0: SetOperation(Operation::SLDT); break;
case 1: SetOperation(Operation::STR); break;
case 2: SetOperation(Operation::LLDT); break;
case 3: SetOperation(Operation::LTR); break;
case 4: SetOperation(Operation::VERR); break;
case 5: SetOperation(Operation::VERW); break;
}
break;
@ -836,12 +841,12 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
switch(reg) {
default: undefined();
case 0: operation_ = Operation::SGDT; break;
case 1: operation_ = Operation::SIDT; break;
case 2: operation_ = Operation::LGDT; break;
case 3: operation_ = Operation::LIDT; break;
case 4: operation_ = Operation::SMSW; break;
case 6: operation_ = Operation::LMSW; break;
case 0: SetOperation(Operation::SGDT); break;
case 1: SetOperation(Operation::SIDT); break;
case 2: SetOperation(Operation::LGDT); break;
case 3: SetOperation(Operation::LIDT); break;
case 4: SetOperation(Operation::SMSW); break;
case 6: SetOperation(Operation::LMSW); break;
}
break;
@ -853,10 +858,10 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
switch(reg) {
default: undefined();
case 4: operation_ = Operation::BT; break;
case 5: operation_ = Operation::BTS; break;
case 6: operation_ = Operation::BTR; break;
case 7: operation_ = Operation::BTC; break;
case 4: SetOperation(Operation::BT); break;
case 5: SetOperation(Operation::BTS); break;
case 6: SetOperation(Operation::BTR); break;
case 7: SetOperation(Operation::BTC); break;
}
break;
@ -871,6 +876,7 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
}
#undef undefined
#undef SetOperation
// MARK: - ScaleIndexBase
@ -913,10 +919,10 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
if(!sign_extend_displacement_) {
switch(displacement_size_) {
case DataSize::None: displacement_ = 0; break;
case DataSize::Byte: displacement_ = decltype(operand_)(uint8_t(inward_data_)); break;
case DataSize::Word: displacement_ = decltype(operand_)(uint16_t(inward_data_)); break;
case DataSize::DWord: displacement_ = decltype(operand_)(uint32_t(inward_data_)); break;
case DataSize::None: displacement_ = 0; break;
case DataSize::Byte: displacement_ = decltype(displacement_)(uint8_t(inward_data_)); break;
case DataSize::Word: displacement_ = decltype(displacement_)(uint16_t(inward_data_)); break;
case DataSize::DWord: displacement_ = decltype(displacement_)(uint32_t(inward_data_)); break;
}
} else {
switch(displacement_size_) {

21
InstructionSets/x86/Instruction.hpp
View File

@ -510,6 +510,27 @@ enum class Repetition: uint8_t {
None, RepE, RepNE
};
constexpr bool supports(Operation operation, Repetition repetition) {
switch(operation) {
default: return false;
case Operation::INS:
case Operation::OUTS:
case Operation::LODS:
return repetition == Repetition::RepE;
case Operation::STOS:
case Operation::MOVS:
case Operation::CMPS:
case Operation::SCAS:
return true;
case Operation::IDIV:
return repetition == Repetition::RepNE;
}
}
/// Provides a 32-bit-style scale, index and base; to produce the address this represents,
/// calcluate base() + (index() << scale()).
///

9
OSBindings/Mac/Clock SignalTests/8088Tests.mm
View File

@ -176,11 +176,16 @@ std::string to_string(InstructionSet::x86::DataPointer pointer, const Instructio
// Form string version, compare.
std::string operation;
// TODO: determine which reps, if any, this operation permits, and print only as relevant.
// TODO: this was a bit of a guess at the logic behind rep versus repe but doesn't seem to fit;
// check more thoroughly.
using Repetition = InstructionSet::x86::Repetition;
switch(instruction.repetition()) {
case Repetition::None: break;
case Repetition::RepE: operation += "repe "; break;
case Repetition::RepE:
operation +=
InstructionSet::x86::supports(instruction.operation, Repetition::RepNE)
? "repe " : "rep ";
break;
case Repetition::RepNE: operation += "repne "; break;
}