fceux/x6502.c

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/* FCE Ultra - NES/Famicom Emulator
*
* Copyright notice for this file:
* Copyright (C) 2002 Xodnizel
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <string.h>
#include "types.h"
#include "x6502.h"
#include "fceu.h"
#include "sound.h"
X6502 X;
#ifdef FCEUDEF_DEBUGGER
void (*X6502_Run)(int32 cycles);
#endif
uint32 timestamp;
void FP_FASTAPASS(1) (*MapIRQHook)(int a);
#define _PC X.PC
#define _A X.A
#define _X X.X
#define _Y X.Y
#define _S X.S
#define _P X.P
#define _PI X.mooPI
#define _DB X.DB
#define _count X.count
#define _tcount X.tcount
#define _IRQlow X.IRQlow
#define _jammed X.jammed
#define ADDCYC(x) \
{ \
int __x=x; \
_tcount+=__x; \
_count-=__x*48; \
timestamp+=__x; \
}
static INLINE uint8 RdMemNorm(unsigned int A)
{
return(_DB=ARead[A](A));
}
static INLINE void WrMemNorm(unsigned int A, uint8 V)
{
BWrite[A](A,V);
}
#ifdef FCEUDEF_DEBUGGER
X6502 XSave; /* This is getting ugly. */
//#define RdMemHook(A) ( X.ReadHook?(_DB=X.ReadHook(&X,A)):(_DB=ARead[A](A)) )
//#define WrMemHook(A,V) { if(X.WriteHook) X.WriteHook(&X,A,V); else BWrite[A](A,V); }
static INLINE uint8 RdMemHook(unsigned int A)
{
if(X.ReadHook)
return(_DB = X.ReadHook(&X,A) );
else
return(_DB=ARead[A](A));
}
static INLINE void WrMemHook(unsigned int A, uint8 V)
{
if(X.WriteHook)
X.WriteHook(&X,A,V);
else
BWrite[A](A,V);
}
#endif
//#define RdRAMFast(A) (_DB=RAM[(A)])
//#define WrRAMFast(A,V) RAM[(A)]=(V)
static INLINE uint8 RdRAMFast(unsigned int A)
{
return(_DB=RAM[A]);
}
static INLINE void WrRAMFast(unsigned int A, uint8 V)
{
RAM[A]=V;
}
uint8 FASTAPASS(1) X6502_DMR(uint32 A)
{
ADDCYC(1);
return(X.DB=ARead[A](A));
}
void FASTAPASS(2) X6502_DMW(uint32 A, uint8 V)
{
ADDCYC(1);
BWrite[A](A,V);
}
#define PUSH(V) \
{ \
uint8 VTMP=V; \
WrRAM(0x100+_S,VTMP); \
_S--; \
}
#define POP() RdRAM(0x100+(++_S))
static uint8 ZNTable[256];
/* Some of these operations will only make sense if you know what the flag
constants are. */
#define X_ZN(zort) _P&=~(Z_FLAG|N_FLAG);_P|=ZNTable[zort]
#define X_ZNT(zort) _P|=ZNTable[zort]
#define JR(cond); \
{ \
if(cond) \
{ \
uint32 tmp; \
int32 disp; \
disp=(int8)RdMem(_PC); \
_PC++; \
ADDCYC(1); \
tmp=_PC; \
_PC+=disp; \
if((tmp^_PC)&0x100) \
ADDCYC(1); \
} \
else _PC++; \
}
#define LDA _A=x;X_ZN(_A)
#define LDX _X=x;X_ZN(_X)
#define LDY _Y=x;X_ZN(_Y)
/* All of the freaky arithmetic operations. */
#define AND _A&=x;X_ZN(_A)
#define BIT _P&=~(Z_FLAG|V_FLAG|N_FLAG);_P|=ZNTable[x&_A]&Z_FLAG;_P|=x&(V_FLAG|N_FLAG)
#define EOR _A^=x;X_ZN(_A)
#define ORA _A|=x;X_ZN(_A)
#define ADC { \
uint32 l=_A+x+(_P&1); \
_P&=~(Z_FLAG|C_FLAG|N_FLAG|V_FLAG); \
_P|=((((_A^x)&0x80)^0x80) & ((_A^l)&0x80))>>1; \
_P|=(l>>8)&C_FLAG; \
_A=l; \
X_ZNT(_A); \
}
#define SBC { \
uint32 l=_A-x-((_P&1)^1); \
_P&=~(Z_FLAG|C_FLAG|N_FLAG|V_FLAG); \
_P|=((_A^l)&(_A^x)&0x80)>>1; \
_P|=((l>>8)&C_FLAG)^C_FLAG; \
_A=l; \
X_ZNT(_A); \
}
#define CMPL(a1,a2) { \
uint32 t=a1-a2; \
X_ZN(t&0xFF); \
_P&=~C_FLAG; \
_P|=((t>>8)&C_FLAG)^C_FLAG; \
}
/* Special undocumented operation. Very similar to CMP. */
#define AXS { \
uint32 t=(_A&_X)-x; \
X_ZN(t&0xFF); \
_P&=~C_FLAG; \
_P|=((t>>8)&C_FLAG)^C_FLAG; \
_X=t; \
}
#define CMP CMPL(_A,x)
#define CPX CMPL(_X,x)
#define CPY CMPL(_Y,x)
/* The following operations modify the byte being worked on. */
#define DEC x--;X_ZN(x)
#define INC x++;X_ZN(x)
#define ASL _P&=~C_FLAG;_P|=x>>7;x<<=1;X_ZN(x)
#define LSR _P&=~(C_FLAG|N_FLAG|Z_FLAG);_P|=x&1;x>>=1;X_ZNT(x)
/* For undocumented instructions, maybe for other things later... */
#define LSRA _P&=~(C_FLAG|N_FLAG|Z_FLAG);_P|=_A&1;_A>>=1;X_ZNT(_A)
#define ROL { \
uint8 l=x>>7; \
x<<=1; \
x|=_P&C_FLAG; \
_P&=~(Z_FLAG|N_FLAG|C_FLAG); \
_P|=l; \
X_ZNT(x); \
}
#define ROR { \
uint8 l=x&1; \
x>>=1; \
x|=(_P&C_FLAG)<<7; \
_P&=~(Z_FLAG|N_FLAG|C_FLAG); \
_P|=l; \
X_ZNT(x); \
}
/* Icky icky thing for some undocumented instructions. Can easily be
broken if names of local variables are changed.
*/
/* Absolute */
#define GetAB(target) \
{ \
target=RdMem(_PC); \
_PC++; \
target|=RdMem(_PC)<<8; \
_PC++; \
}
/* Absolute Indexed(for reads) */
#define GetABIRD(target, i) \
{ \
unsigned int tmp; \
GetAB(tmp); \
target=tmp; \
target+=i; \
if((target^tmp)&0x100) \
{ \
target&=0xFFFF; \
RdMem(target^0x100); \
ADDCYC(1); \
} \
}
/* Absolute Indexed(for writes and rmws) */
#define GetABIWR(target, i) \
{ \
unsigned int rt; \
GetAB(rt); \
target=rt; \
target+=i; \
target&=0xFFFF; \
RdMem((target&0x00FF)|(rt&0xFF00)); \
}
/* Zero Page */
#define GetZP(target) \
{ \
target=RdMem(_PC); \
_PC++; \
}
/* Zero Page Indexed */
#define GetZPI(target,i) \
{ \
target=i+RdMem(_PC); \
_PC++; \
}
/* Indexed Indirect */
#define GetIX(target) \
{ \
uint8 tmp; \
tmp=RdMem(_PC); \
_PC++; \
tmp+=_X; \
target=RdRAM(tmp); \
tmp++; \
target|=RdRAM(tmp)<<8; \
}
/* Indirect Indexed(for reads) */
#define GetIYRD(target) \
{ \
unsigned int rt; \
uint8 tmp; \
tmp=RdMem(_PC); \
_PC++; \
rt=RdRAM(tmp); \
tmp++; \
rt|=RdRAM(tmp)<<8; \
target=rt; \
target+=_Y; \
if((target^rt)&0x100) \
{ \
target&=0xFFFF; \
RdMem(target^0x100); \
ADDCYC(1); \
} \
}
/* Indirect Indexed(for writes and rmws) */
#define GetIYWR(target) \
{ \
unsigned int rt; \
uint8 tmp; \
tmp=RdMem(_PC); \
_PC++; \
rt=RdRAM(tmp); \
tmp++; \
rt|=RdRAM(tmp)<<8; \
target=rt; \
target+=_Y; \
target&=0xFFFF; \
RdMem((target&0x00FF)|(rt&0xFF00)); \
}
/* Now come the macros to wrap up all of the above stuff addressing mode functions
and operation macros. Note that operation macros will always operate(redundant
redundant) on the variable "x".
*/
#define RMW_A(op) {uint8 x=_A; op; _A=x; break; } /* Meh... */
#define RMW_AB(op) {unsigned int A; uint8 x; GetAB(A); x=RdMem(A); WrMem(A,x); op; WrMem(A,x); break; }
#define RMW_ABI(reg,op) {unsigned int A; uint8 x; GetABIWR(A,reg); x=RdMem(A); WrMem(A,x); op; WrMem(A,x); break; }
#define RMW_ABX(op) RMW_ABI(_X,op)
#define RMW_ABY(op) RMW_ABI(_Y,op)
#define RMW_IX(op) {unsigned int A; uint8 x; GetIX(A); x=RdMem(A); WrMem(A,x); op; WrMem(A,x); break; }
#define RMW_IY(op) {unsigned int A; uint8 x; GetIYWR(A); x=RdMem(A); WrMem(A,x); op; WrMem(A,x); break; }
#define RMW_ZP(op) {uint8 A; uint8 x; GetZP(A); x=RdRAM(A); op; WrRAM(A,x); break; }
#define RMW_ZPX(op) {uint8 A; uint8 x; GetZPI(A,_X); x=RdRAM(A); op; WrRAM(A,x); break;}
#define LD_IM(op) {uint8 x; x=RdMem(_PC); _PC++; op; break;}
#define LD_ZP(op) {uint8 A; uint8 x; GetZP(A); x=RdRAM(A); op; break;}
#define LD_ZPX(op) {uint8 A; uint8 x; GetZPI(A,_X); x=RdRAM(A); op; break;}
#define LD_ZPY(op) {uint8 A; uint8 x; GetZPI(A,_Y); x=RdRAM(A); op; break;}
#define LD_AB(op) {unsigned int A; uint8 x; GetAB(A); x=RdMem(A); op; break; }
#define LD_ABI(reg,op) {unsigned int A; uint8 x; GetABIRD(A,reg); x=RdMem(A); op; break;}
#define LD_ABX(op) LD_ABI(_X,op)
#define LD_ABY(op) LD_ABI(_Y,op)
#define LD_IX(op) {unsigned int A; uint8 x; GetIX(A); x=RdMem(A); op; break;}
#define LD_IY(op) {unsigned int A; uint8 x; GetIYRD(A); x=RdMem(A); op; break;}
#define ST_ZP(r) {uint8 A; GetZP(A); WrRAM(A,r); break;}
#define ST_ZPX(r) {uint8 A; GetZPI(A,_X); WrRAM(A,r); break;}
#define ST_ZPY(r) {uint8 A; GetZPI(A,_Y); WrRAM(A,r); break;}
#define ST_AB(r) {unsigned int A; GetAB(A); WrMem(A,r); break;}
#define ST_ABI(reg,r) {unsigned int A; GetABIWR(A,reg); WrMem(A,r); break; }
#define ST_ABX(r) ST_ABI(_X,r)
#define ST_ABY(r) ST_ABI(_Y,r)
#define ST_IX(r) {unsigned int A; GetIX(A); WrMem(A,r); break; }
#define ST_IY(r) {unsigned int A; GetIYWR(A); WrMem(A,r); break; }
static uint8 CycTable[256] =
{
/*0x00*/ 7,6,2,8,3,3,5,5,3,2,2,2,4,4,6,6,
/*0x10*/ 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,
/*0x20*/ 6,6,2,8,3,3,5,5,4,2,2,2,4,4,6,6,
/*0x30*/ 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,
/*0x40*/ 6,6,2,8,3,3,5,5,3,2,2,2,3,4,6,6,
/*0x50*/ 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,
/*0x60*/ 6,6,2,8,3,3,5,5,4,2,2,2,5,4,6,6,
/*0x70*/ 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,
/*0x80*/ 2,6,2,6,3,3,3,3,2,2,2,2,4,4,4,4,
/*0x90*/ 2,6,2,6,4,4,4,4,2,5,2,5,5,5,5,5,
/*0xA0*/ 2,6,2,6,3,3,3,3,2,2,2,2,4,4,4,4,
/*0xB0*/ 2,5,2,5,4,4,4,4,2,4,2,4,4,4,4,4,
/*0xC0*/ 2,6,2,8,3,3,5,5,2,2,2,2,4,4,6,6,
/*0xD0*/ 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,
/*0xE0*/ 2,6,3,8,3,3,5,5,2,2,2,2,4,4,6,6,
/*0xF0*/ 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,
};
void FASTAPASS(1) X6502_IRQBegin(int w)
{
_IRQlow|=w;
}
void FASTAPASS(1) X6502_IRQEnd(int w)
{
_IRQlow&=~w;
}
void TriggerNMI(void)
{
_IRQlow|=FCEU_IQNMI;
}
void TriggerNMI2(void)
{
_IRQlow|=FCEU_IQNMI2;
}
#ifdef FCEUDEF_DEBUGGER
/* Called from debugger. */
void FCEUI_NMI(void)
{
_IRQlow|=FCEU_IQNMI;
}
void FCEUI_IRQ(void)
{
_IRQlow|=FCEU_IQTEMP;
}
void FCEUI_GetIVectors(uint16 *reset, uint16 *irq, uint16 *nmi)
{
fceuindbg=1;
*reset=RdMemNorm(0xFFFC);
*reset|=RdMemNorm(0xFFFD)<<8;
*nmi=RdMemNorm(0xFFFA);
*nmi|=RdMemNorm(0xFFFB)<<8;
*irq=RdMemNorm(0xFFFE);
*irq|=RdMemNorm(0xFFFF)<<8;
fceuindbg=0;
}
static int debugmode;
#endif
void X6502_Reset(void)
{
_IRQlow=FCEU_IQRESET;
}
void X6502_Init(void)
{
int x;
memset((void *)&X,0,sizeof(X));
for(x=0;x<256;x++)
if(!x) ZNTable[x]=Z_FLAG;
else if(x&0x80) ZNTable[x]=N_FLAG;
else ZNTable[x]=0;
#ifdef FCEUDEF_DEBUGGER
X6502_Debug(0,0,0);
#endif
}
void X6502_Power(void)
{
_count=_tcount=_IRQlow=_PC=_A=_X=_Y=_S=_P=_PI=_DB=_jammed=0;
timestamp=0;
X6502_Reset();
}
#ifdef FCEUDEF_DEBUGGER
static void X6502_RunDebug(int32 cycles)
{
#define RdRAM RdMemHook
#define WrRAM WrMemHook
#define RdMem RdMemHook
#define WrMem WrMemHook
if(PAL)
cycles*=15; // 15*4=60
else
cycles*=16; // 16*4=64
_count+=cycles;
while(_count>0)
{
int32 temp;
uint8 b1;
if(_IRQlow)
{
if(_IRQlow&FCEU_IQRESET)
{
_PC=RdMem(0xFFFC);
_PC|=RdMem(0xFFFD)<<8;
_jammed=0;
_PI=_P=I_FLAG;
_IRQlow&=~FCEU_IQRESET;
}
else if(_IRQlow&FCEU_IQNMI2)
{
_IRQlow&=~FCEU_IQNMI2;
_IRQlow|=FCEU_IQNMI;
}
else if(_IRQlow&FCEU_IQNMI)
{
if(!_jammed)
{
ADDCYC(7);
PUSH(_PC>>8);
PUSH(_PC);
PUSH((_P&~B_FLAG)|(U_FLAG));
_P|=I_FLAG;
_PC=RdMem(0xFFFA);
_PC|=RdMem(0xFFFB)<<8;
_IRQlow&=~FCEU_IQNMI;
}
}
else
{
if(!(_PI&I_FLAG) && !_jammed)
{
ADDCYC(7);
PUSH(_PC>>8);
PUSH(_PC);
PUSH((_P&~B_FLAG)|(U_FLAG));
_P|=I_FLAG;
_PC=RdMem(0xFFFE);
_PC|=RdMem(0xFFFF)<<8;
}
}
_IRQlow&=~(FCEU_IQTEMP);
if(_count<=0)
{
_PI=_P;
return;
} /* Should increase accuracy without a */
/* major speed hit. */
}
if(X.CPUHook) X.CPUHook(&X);
/* Ok, now the real fun starts. */
/* Do the pre-exec voodoo. */
if(X.ReadHook || X.WriteHook)
{
uint32 tsave=timestamp;
XSave=X;
fceuindbg=1;
X.preexec=1;
b1=RdMem(_PC);
_PC++;
switch(b1)
{
#include "ops.h"
}
timestamp=tsave;
/* In case an NMI/IRQ/RESET was triggered by the debugger. */
/* Should we also copy over the other hook variables? */
XSave.IRQlow=X.IRQlow;
XSave.ReadHook=X.ReadHook;
XSave.WriteHook=X.WriteHook;
XSave.CPUHook=X.CPUHook;
X=XSave;
fceuindbg=0;
}
_PI=_P;
b1=RdMem(_PC);
ADDCYC(CycTable[b1]);
temp=_tcount;
_tcount=0;
if(MapIRQHook) MapIRQHook(temp);
FCEU_SoundCPUHook(temp);
_PC++;
switch(b1)
{
#include "ops.h"
}
}
#undef RdRAM
#undef WrRAM
#undef RdMem
#undef WrMem
}
static void X6502_RunNormal(int32 cycles)
#else
void X6502_Run(int32 cycles)
#endif
{
#define RdRAM RdRAMFast
#define WrRAM WrRAMFast
#define RdMem RdMemNorm
#define WrMem WrMemNorm
#if(defined(C80x86) && defined(__GNUC__))
/* Gives a nice little speed boost. */
register uint16 pbackus asm ("edi");
#else
uint16 pbackus;
#endif
pbackus=_PC;
#undef _PC
#define _PC pbackus
if(PAL)
cycles*=15; // 15*4=60
else
cycles*=16; // 16*4=64
_count+=cycles;
while(_count>0)
{
int32 temp;
uint8 b1;
// XI.PC=pbackus;
if(_IRQlow)
{
if(_IRQlow&FCEU_IQRESET)
{
_PC=RdMem(0xFFFC);
_PC|=RdMem(0xFFFD)<<8;
_jammed=0;
_PI=_P=I_FLAG;
_IRQlow&=~FCEU_IQRESET;
}
else if(_IRQlow&FCEU_IQNMI2)
{
_IRQlow&=~FCEU_IQNMI2;
_IRQlow|=FCEU_IQNMI;
}
else if(_IRQlow&FCEU_IQNMI)
{
if(!_jammed)
{
ADDCYC(7);
PUSH(_PC>>8);
PUSH(_PC);
PUSH((_P&~B_FLAG)|(U_FLAG));
_P|=I_FLAG;
_PC=RdMem(0xFFFA);
_PC|=RdMem(0xFFFB)<<8;
_IRQlow&=~FCEU_IQNMI;
}
}
else
{
if(!(_PI&I_FLAG) && !_jammed)
{
ADDCYC(7);
PUSH(_PC>>8);
PUSH(_PC);
PUSH((_P&~B_FLAG)|(U_FLAG));
_P|=I_FLAG;
_PC=RdMem(0xFFFE);
_PC|=RdMem(0xFFFF)<<8;
}
}
_IRQlow&=~(FCEU_IQTEMP);
if(_count<=0)
{
_PI=_P;
X.PC=pbackus;
return;
} /* Should increase accuracy without a */
/* major speed hit. */
}
_PI=_P;
b1=RdMem(_PC);
ADDCYC(CycTable[b1]);
temp=_tcount;
_tcount=0;
if(MapIRQHook) MapIRQHook(temp);
FCEU_SoundCPUHook(temp);
//printf("%04x\n",X.PC);
X.PC=pbackus;
_PC++;
switch(b1)
{
#include "ops.h"
}
}
#undef _PC
#define _PC X.PC
_PC=pbackus;
#undef RdRAM
#undef WrRAM
}
#ifdef FCEUDEF_DEBUGGER
void X6502_Debug(void (*CPUHook)(X6502 *),
uint8 (*ReadHook)(X6502 *, unsigned int),
void (*WriteHook)(X6502 *, unsigned int, uint8))
{
debugmode=(ReadHook || WriteHook || CPUHook)?1:0;
X.ReadHook=ReadHook;
X.WriteHook=WriteHook;
X.CPUHook=CPUHook;
if(!debugmode)
X6502_Run=X6502_RunNormal;
else
X6502_Run=X6502_RunDebug;
}
#endif