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Add EXG, ABCD, SBCD.

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This commit is contained in:
Thomas Harte 2022-05-19 15:19:00 -04:00
parent 0471decfc8
commit ce7f94559b
1 changed files with 43 additions and 1 deletions
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44
Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
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@ -68,6 +68,8 @@ enum ExecutionState: int {
MOVEw,
MOVEwRegisterDirect,
MOVEwAddressRegisterIndirectWithPostincrement,
SABCD_PreDec,
};
// MARK: - The state machine.
@ -288,6 +290,7 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
})
StdCASE(SWAP, perform_state_ = Perform_np);
StdCASE(EXG, perform_state_ = Perform_np_n);
StdCASE(MOVEw, perform_state_ = MOVEw);
@ -344,6 +347,24 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
}
})
CASE(SBCD)
if(instruction_.mode(0) == Mode::DataRegisterDirect) {
perform_state_ = Perform_np_n;
SetupDataAccess(Microcycle::Read, Microcycle::SelectByte);
MoveToState(FetchOperand_bw);
} else {
MoveToState(SABCD_PreDec);
}
CASE(ABCD)
if(instruction_.mode(0) == Mode::DataRegisterDirect) {
perform_state_ = Perform_np_n;
SetupDataAccess(Microcycle::Read, Microcycle::SelectByte);
MoveToState(FetchOperand_bw);
} else {
MoveToState(SABCD_PreDec);
}
default:
assert(false);
}
@ -766,7 +787,6 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
default: assert(false);
}
BeginState(MOVEwRegisterDirect):
registers_[instruction_.lreg(1)].w = operand_[1].w;
Prefetch(); // np
@ -778,6 +798,28 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
Prefetch() // np
MoveToState(Decode);
BeginState(SABCD_PreDec):
IdleBus(1); // n
SetupDataAccess(Microcycle::Read, Microcycle::SelectByte);
registers_[8 + instruction_.reg(0)].l -= byte_word_increments[0][instruction_.reg(0)];
SetDataAddress(registers_[8 + instruction_.reg(0)].l);
Access(operand_[0].low); // nr
registers_[8 + instruction_.reg(1)].l -= byte_word_increments[1][instruction_.reg(1)];
SetDataAddress(registers_[8 + instruction_.reg(1)].l);
Access(operand_[1].low); // nr
Prefetch(); // np
InstructionSet::M68k::perform<InstructionSet::M68k::Model::M68000>(
instruction_, operand_[0], operand_[1], status_, *static_cast<ProcessorBase *>(this));
SetupDataAccess(0, Microcycle::SelectByte);
Access(operand_[1].low); // nw
MoveToState(Decode);
// Various states TODO.
#define TODOState(x) \
BeginState(x): [[fallthrough]];