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Attempt CMPS, changing storage of direction; add flags check.

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This commit is contained in:
Thomas Harte
2023-10-19 14:07:59 -04:00
parent 617be7cba7
commit f715cd89a9
3 changed files with 160 additions and 59 deletions
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71
InstructionSets/x86/Implementation/PerformImplementation.hpp
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@@ -1354,6 +1354,72 @@ void pushf(MemoryT &memory, RegistersT &registers, Status &status) {
push<uint16_t>(value, memory, registers);
}
template <typename AddressT, typename InstructionT, typename RegistersT>
bool repetition_over(const InstructionT &instruction, RegistersT &registers) {
if(instruction.repetition() == Repetition::None) {
return false;
}
if constexpr (std::is_same_v<AddressT, uint16_t>) {
return !registers.cx();
} else {
return !registers.ecx();
}
}
template <typename AddressT, typename InstructionT, typename RegistersT, typename FlowControllerT>
void repeat(const InstructionT &instruction, Status &status, RegistersT &registers, FlowControllerT &flow_controller) {
if(instruction.repetition() == Repetition::None) {
return;
}
bool count_exhausted = false;
if constexpr (std::is_same_v<AddressT, uint16_t>) {
count_exhausted = !(--registers.cx());
} else {
count_exhausted = !(--registers.ecx());
}
if(count_exhausted) {
return;
}
const bool zero = status.flag<Flag::Zero>();
if(instruction.repetition() == Repetition::RepE && !zero) {
return;
} else if(instruction.repetition() == Repetition::RepNE && zero) {
return;
}
flow_controller.repeat_last();
}
template <typename IntT, typename AddressT, typename InstructionT, typename MemoryT, typename RegistersT, typename FlowControllerT>
void cmps(const InstructionT &instruction, MemoryT &memory, RegistersT &registers, Status &status, FlowControllerT &flow_controller) {
if(repetition_over<AddressT>(instruction, registers)) {
return;
}
Source source_segment = instruction.segment_override();
if(source_segment == Source::None) source_segment = Source::DS;
if constexpr (std::is_same_v<AddressT, uint16_t>) {
IntT source = memory.template access<IntT>(source_segment, registers.si());
IntT destination = memory.template access<IntT>(Source::ES, registers.di());
Primitive::sub<false, false>(destination, source, status);
registers.si() += status.direction<AddressT>();
registers.di() += status.direction<AddressT>();
} else {
IntT source = memory.template access<IntT>(source_segment, registers.esi());
IntT destination = memory.template access<IntT>(Source::ES, registers.edi());
Primitive::sub<false, false>(destination, source, status);
registers.esi() += status.direction<AddressT>();
registers.edi() += status.direction<AddressT>();
}
repeat<AddressT>(instruction, status, registers, flow_controller);
}
}
template <
@@ -1569,6 +1635,11 @@ template <
case Operation::PUSH: Primitive::push<IntT>(source(), memory, registers); break;
case Operation::POPF: Primitive::popf(memory, registers, status); break;
case Operation::PUSHF: Primitive::pushf(memory, registers, status); break;
// TODO: don't assume address size below.
case Operation::CMPS:
Primitive::cmps<IntT, uint16_t>(instruction, memory, registers, status, flow_controller);
break;
}
// Write to memory if required to complete this operation.