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Implement MOVEM to memory.

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This commit is contained in:
Thomas Harte
2022-05-05 18:51:29 -04:00
parent 47f4bbeec6
commit d7d0a5c15e
3 changed files with 50 additions and 7 deletions
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46
InstructionSets/M68k/Implementation/ExecutorImplementation.hpp
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@@ -440,11 +440,51 @@ void Executor<model, BusHandler>::movep(Preinstruction instruction, uint32_t sou
template <Model model, typename BusHandler>
template <typename IntT>
void Executor<model, BusHandler>::movem(Preinstruction instruction, uint32_t source, uint32_t dest) {
if(instruction.mode<0>() == AddressingMode::DataRegisterDirect) {
// Move registers to memory.
// NB:
//
// "For the MC68020, MC68030, MC68040, and CPU32, if the addressing register is also
// moved to memory, the value written is the initial register value decremented by the
// size of the operation. The MC68000 and MC68010 write the initial register value
// (not decremented)."
if(instruction.mode<0>() == AddressingMode::ImmediateData) {
// Move registers to memory. This is the only permitted use of the predecrement mode,
// which reverses output order.
if(instruction.mode<1>() == AddressingMode::AddressRegisterIndirectWithPredecrement) {
} else {
// The structure of the code in the mainline part of the executor is such
// that the address register will already have been predecremented before
// reaching here, and it'll have been by two bytes per the operand size
// rather than according to the instruction size. That's not wanted, so undo it.
//
// (TODO: with the caveat that the 68020+ have different behaviour.).
registers_[8 + instruction.reg<1>()].l += 2;
uint32_t reg = registers_[8 + instruction.reg<1>()].l;
int index = 15;
while(source) {
if(source & 1) {
reg -= sizeof(IntT);
bus_handler_.template write<IntT>(reg, IntT(registers_[index].l));
}
--index;
source >>= 1;
}
registers_[8 + instruction.reg<1>()].l = reg;
return;
}
int index = 0;
while(source) {
if(source & 1) {
bus_handler_.template write<IntT>(dest, IntT(registers_[index].l));
dest += sizeof(IntT);
}
++index;
source >>= 1;
}
} else {
// Move memory to registers.
}