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Merge pull request #33 from TomHarte/NMI

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Made an attempt to implement NMI
This commit is contained in:
Thomas Harte 2016-06-27 22:06:26 -04:00 committed by GitHub
commit 24280844cb
1 changed files with 31 additions and 8 deletions
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39
Processors/6502/CPU6502.hpp
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@ -120,7 +120,9 @@ template <class T> class Processor {
OperationSBX, OperationLXA, OperationANE, OperationANC,
OperationLAS, CycleAddSignedOperandToPC, OperationSetFlagsFromOperand, OperationSetOperandFromFlagsWithBRKSet,
OperationSetOperandFromFlags,
OperationSetFlagsFromA, CycleReadRSTLow, CycleReadRSTHigh, CycleScheduleJam
OperationSetFlagsFromA,
CycleReadRSTLow, CycleReadRSTHigh, CycleReadNMILow, CycleReadNMIHigh,
CycleScheduleJam
};
#define JAM {CycleFetchOperand, CycleScheduleJam, OperationMoveToNextProgram}
@ -496,6 +498,24 @@ template <class T> class Processor {
return reset;
}
/*!
Gets the program representing an NMI response.
@returns The program representing an NMI response.
*/
inline const MicroOp *get_nmi_program() {
static const MicroOp reset[] = {
CyclePushPCH,
CyclePushPCL,
OperationSetOperandFromFlags,
CyclePushOperand,
CycleReadNMILow,
CycleReadNMIHigh,
OperationMoveToNextProgram
};
return reset;
}
protected:
Processor() :
_scheduleProgramsReadPointer(0),
@ -558,11 +578,13 @@ template <class T> class Processor {
scheduleProgramsReadPointer = _scheduleProgramsWritePointer = scheduleProgramProgramCounter = 0;\
if(_reset_line_is_enabled) {\
schedule_program(get_reset_program());\
} else if(_nmi_line_is_enabled) {\
_nmi_line_is_enabled = false;\
schedule_program(get_nmi_program());\
} else if(_irq_request_history[0]) {\
schedule_program(get_irq_program());\
} else {\
if(_irq_request_history[0])\
schedule_program(get_irq_program());\
else\
schedule_program(fetch_decode_execute);\
schedule_program(fetch_decode_execute);\
}\
op;\
}
@ -649,6 +671,8 @@ template <class T> class Processor {
case CycleReadFromS: throwaway_read(_s | 0x100); break;
case CycleReadFromPC: throwaway_read(_pc.full); break;
case CycleReadNMILow: read_mem(_pc.bytes.low, 0xfffa); break;
case CycleReadNMIHigh: read_mem(_pc.bytes.high, 0xfffb); break;
case CycleReadRSTLow: read_mem(_pc.bytes.low, 0xfffc); break;
case CycleReadRSTHigh: read_mem(_pc.bytes.high, 0xfffd); break;
case CycleSetIReadBRKLow: _interruptFlag = Flag::Interrupt; read_mem(_pc.bytes.low, 0xfffe); break;
@ -1177,9 +1201,8 @@ template <class T> class Processor {
*/
inline void set_nmi_line(bool active)
{
// TODO: NMI is edge triggered, not level, and in any case _nmi_line_is_enabled
// is not honoured elsewhere. So NMI is yet to be implemented.
_nmi_line_is_enabled = active;
// NMI is edge triggered, not level
_nmi_line_is_enabled |= active;
}
/*!