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

7
InstructionSets/M68k/Sequence.cpp
View File

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

17
InstructionSets/M68k/Sequence.hpp
View File

@ -35,6 +35,12 @@ enum class Step {
StoreOp1, StoreOp1,
/// Store the value of operand 2. /// Store the value of operand 2.
StoreOp2, 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, /// 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 /// if no further steps remain. This step is removed from the
/// list of remaining steps. /// list of remaining steps.
Step pop_front() { Step pop_front() {
const auto step = Step(steps_ & 7); static_assert(int(Step::Max) < 16);
steps_ >>= 3; const auto step = Step(steps_ & 15);
steps_ >>= 4;
return step; return step;
} }
@ -59,12 +66,12 @@ template<Model model> class Sequence {
} }
private: 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));
} }
} }