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Add MULU/S functionality, though not timing.

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This commit is contained in:
Thomas Harte 2022-05-22 08:02:32 -04:00
parent 4a6512f5d5
commit 3c1c4f89e9
2 changed files with 31 additions and 2 deletions
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29
Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
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@ -162,6 +162,7 @@ enum ExecutionState: int {
MOVEMtoM_finish,
DIVU_DIVS,
MULU_MULS,
};
// MARK: - The state machine.
@ -697,6 +698,8 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
StdCASE(DIVU, perform_state_ = DIVU_DIVS);
StdCASE(DIVS, perform_state_ = DIVU_DIVS);
StdCASE(MULU, perform_state_ = MULU_MULS);
StdCASE(MULS, perform_state_ = MULU_MULS);
default:
assert(false);
@ -1854,6 +1857,24 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
Prefetch(); // np
MoveToStateSpecific(Decode);
//
// MULU and MULS
//
BeginState(MULU_MULS):
Prefetch(); // np
// Perform the instruction.
PerformDynamic();
// Delay the correct amount of time.
IdleBus(dynamic_instruction_length_);
// MULU and MULS are always to a register, so just write back here
// to save on dispatch costs.
registers_[instruction_.reg(1)] = operand_[1];
MoveToStateSpecific(Decode);
//
// Various states TODO.
//
@ -1951,6 +1972,14 @@ template <bool did_overflow> void ProcessorBase::did_divs(int32_t, int32_t) {
// TODO: calculate cost.
}
template <typename IntT> void ProcessorBase::did_mulu(IntT) {
// TODO: calculate cost.
}
template <typename IntT> void ProcessorBase::did_muls(IntT) {
// TODO: calculate cost.
}
template <bool use_current_instruction_pc> void ProcessorBase::raise_exception(int vector) {
// No overt action is taken here; instructions that might throw an exception are required
// to check-in after the fact.

4
Processors/68000Mk2/Implementation/68000Mk2Storage.hpp
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@ -122,8 +122,8 @@ struct ProcessorBase: public InstructionSet::M68k::NullFlowController {
// Flow controller... many TODO.
using Preinstruction = InstructionSet::M68k::Preinstruction;
template <typename IntT> void did_mulu(IntT) {} //
template <typename IntT> void did_muls(IntT) {} //
template <typename IntT> void did_mulu(IntT);
template <typename IntT> void did_muls(IntT);
inline void did_chk(bool, bool);
inline void did_scc(bool);
inline void did_shift(int) {} //