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Introduce calculate EA steps.

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This commit is contained in:
Thomas Harte 2022-04-29 20:30:48 -04:00
parent 9359f6477b
commit e4426dc952
3 changed files with 18 additions and 10 deletions
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4
InstructionSets/M68k/Implementation/PerformImplementation.hpp
View File

@ -399,7 +399,7 @@ template <
// JMP: copies EA(0) to the program counter.
case Operation::JMP:
flow_controller.set_pc(flow_controller.effective_address(0));
flow_controller.set_pc(src.l);
break;
/*
@ -438,7 +438,7 @@ template <
break;
case Operation::LEA:
dest.l = flow_controller.effective_address(0);
dest.l = src.l;
break;
// case Operation::PEA:

7
InstructionSets/M68k/Sequence.cpp
View File

@ -11,14 +11,14 @@
using namespace InstructionSet::M68k;
template <Step... T> struct Steps {
static constexpr uint16_t value = 0;
static constexpr uint32_t value = 0;
};
template <Step F, Step... T> struct Steps<F, T...> {
static constexpr uint16_t value = uint16_t(F) | uint16_t(Steps<T...>::value << 3);
static constexpr uint32_t value = uint16_t(F) | uint16_t(Steps<T...>::value << 4);
};
template<Model model> uint16_t Sequence<model>::steps_for(Operation operation) {
template<Model model> uint32_t Sequence<model>::steps_for(Operation operation) {
switch(operation) {
// This handles a NOP, and not much else.
default: return 0;
@ -28,6 +28,7 @@ template<Model model> uint16_t Sequence<model>::steps_for(Operation operation) {
//
case Operation::LEA:
return Steps<
Step::CalcEA1,
Step::Perform
>::value;

17
InstructionSets/M68k/Sequence.hpp
View File

@ -35,6 +35,12 @@ enum class Step {
StoreOp1,
/// Store the value of operand 2.
StoreOp2,
/// Calculate effective address of operand 1.
CalcEA1,
/// Calculate effective address of operand 2.
CalcEA2,
Max = CalcEA2
};
/// Indicates the abstract steps necessary to perform an operation,
@ -47,8 +53,9 @@ template<Model model> class Sequence {
/// if no further steps remain. This step is removed from the
/// list of remaining steps.
Step pop_front() {
const auto step = Step(steps_ & 7);
steps_ >>= 3;
static_assert(int(Step::Max) < 16);
const auto step = Step(steps_ & 15);
steps_ >>= 4;
return step;
}
@ -59,12 +66,12 @@ template<Model model> class Sequence {
}
private:
uint16_t steps_ = 0;
uint32_t steps_ = 0;
uint16_t steps_for(Operation);
uint32_t steps_for(Operation);
};
static_assert(sizeof(Sequence<Model::M68000>) == sizeof(uint16_t));
static_assert(sizeof(Sequence<Model::M68000>) == sizeof(uint32_t));
}
}