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gstreamer/gst/nsf/nes6502.c
Wim Taymans aae22fa1c9 Added NSF decoder plugin. Fixes 151192. 
Original commit message from CVS:
Based on patches by: Johan Dahlin <johan at gnome dot org>
Ronald Bultje <rbultje at ronald dot bitfreak dot net>
* configure.ac:
* gst/nsf/Makefile.am:
* gst/nsf/dis6502.h:
* gst/nsf/fds_snd.c:
* gst/nsf/fds_snd.h:
* gst/nsf/fmopl.c:
* gst/nsf/fmopl.h:
* gst/nsf/gstnsf.c:
* gst/nsf/gstnsf.h:
* gst/nsf/log.c:
* gst/nsf/log.h:
* gst/nsf/memguard.c:
* gst/nsf/memguard.h:
* gst/nsf/mmc5_snd.c:
* gst/nsf/mmc5_snd.h:
* gst/nsf/nes6502.c:
* gst/nsf/nes6502.h:
* gst/nsf/nes_apu.c:
* gst/nsf/nes_apu.h:
* gst/nsf/nsf.c:
* gst/nsf/nsf.h:
* gst/nsf/osd.h:
* gst/nsf/types.h:
* gst/nsf/vrc7_snd.c:
* gst/nsf/vrc7_snd.h:
* gst/nsf/vrcvisnd.c:
* gst/nsf/vrcvisnd.h:
Added NSF decoder plugin. Fixes 151192.
2006-07-13 15:07:28 +00:00

2438 lines
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/*
** Nofrendo (c) 1998-2000 Matthew Conte (matt@conte.com)
**
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of version 2 of the GNU Library General
** Public License as published by the Free Software Foundation.
**
** 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
** Library General Public License for more details. To obtain a
** copy of the GNU Library General Public License, write to the Free
** Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
**
** Any permitted reproduction of these routines, in whole or in part,
** must bear this legend.
**
**
** nes6502.c
**
** NES custom 6502 (2A03) CPU implementation
** $Id$
*/
#include "types.h"
#include "nes6502.h"
#include "dis6502.h"
#include <stdio.h>
#define ADD_CYCLES(x) instruction_cycles += (x)
#define INC_CYCLES() instruction_cycles++
/* #define ADD_CYCLES(x) remaining_cycles -= (x) */
/* #define INC_CYCLES() remaining_cycles-- */
/*
** Check to see if an index reg addition overflowed to next page
*/
#define CHECK_INDEX_OVERFLOW(addr, reg) \
{ \
if ((uint8) (addr) < (reg)) \
INC_CYCLES(); \
}
/*
** Addressing mode macros
*/
#define NO_READ(value) /* empty */
#define IMMEDIATE_BYTE(value) \
{ \
value = bank_readbyte(PC++); \
}
#define ABSOLUTE_ADDR(address) \
{ \
address = bank_readaddress(PC); \
PC += 2; \
}
#define ABSOLUTE(address, value) \
{ \
ABSOLUTE_ADDR(address); \
value = mem_read(address); \
}
#define ABSOLUTE_BYTE(value) \
{ \
ABSOLUTE(temp, value); \
}
#define ABS_IND_X_ADDR(address) \
{ \
address = (bank_readaddress(PC) + X) & 0xFFFF; \
PC += 2; \
CHECK_INDEX_OVERFLOW(address, X); \
}
#define ABS_IND_X(address, value) \
{ \
ABS_IND_X_ADDR(address); \
value = mem_read(address); \
}
#define ABS_IND_X_BYTE(value) \
{ \
ABS_IND_X(temp, value); \
}
#define ABS_IND_Y_ADDR(address) \
{ \
address = (bank_readaddress(PC) + Y) & 0xFFFF; \
PC += 2; \
CHECK_INDEX_OVERFLOW(address, Y); \
}
#define ABS_IND_Y(address, value) \
{ \
ABS_IND_Y_ADDR(address); \
value = mem_read(address); \
}
#define ABS_IND_Y_BYTE(value) \
{ \
ABS_IND_Y(temp, value); \
}
#define ZERO_PAGE_ADDR(address) \
{ \
IMMEDIATE_BYTE(address); \
}
#define ZERO_PAGE(address, value) \
{ \
ZERO_PAGE_ADDR(address); \
value = ZP_READ(address); \
}
#define ZERO_PAGE_BYTE(value) \
{ \
ZERO_PAGE(btemp, value); \
}
/* Zero-page indexed Y doesn't really exist, just for LDX / STX */
#define ZP_IND_X_ADDR(address) \
{ \
address = bank_readbyte(PC++) + X; \
}
#define ZP_IND_X(bAddr, value) \
{ \
ZP_IND_X_ADDR(bAddr); \
value = ZP_READ(bAddr); \
}
#define ZP_IND_X_BYTE(value) \
{ \
ZP_IND_X(btemp, value); \
}
#define ZP_IND_Y_ADDR(address) \
{ \
address = bank_readbyte(PC++) + Y; \
}
#define ZP_IND_Y(address, value) \
{ \
ZP_IND_Y_ADDR(address); \
value = ZP_READ(address); \
}
#define ZP_IND_Y_BYTE(value) \
{ \
ZP_IND_Y(btemp, value); \
}
/*
** For conditional jump relative instructions
** (BCC, BCS, BEQ, BMI, BNE, BPL, BVC, BVS)
*/
#define RELATIVE_JUMP(cond) \
{ \
if (cond) \
{ \
IMMEDIATE_BYTE(btemp); \
if (((int8) btemp + (uint8) PC) & 0xFF00) \
ADD_CYCLES(4); \
else \
ADD_CYCLES(3); \
PC += ((int8) btemp); \
} \
else \
{ \
PC++; \
ADD_CYCLES(2); \
} \
}
/*
** This is actually indexed indirect, but I call it
** indirect X to avoid confusion
*/
#define INDIR_X_ADDR(address) \
{ \
btemp = bank_readbyte(PC++) + X; \
address = zp_address(btemp); \
}
#define INDIR_X(address, value) \
{ \
INDIR_X_ADDR(address); \
value = mem_read(address); \
}
#define INDIR_X_BYTE(value) \
{ \
INDIR_X(temp, value); \
}
/*
** This is actually indirect indexed, but I call it
** indirect y to avoid confusion
*/
#define INDIR_Y_ADDR(address) \
{ \
IMMEDIATE_BYTE(btemp); \
address = (zp_address(btemp) + Y) & 0xFFFF; \
/* ???? */ \
CHECK_INDEX_OVERFLOW(address, Y); \
}
#define INDIR_Y(address, value) \
{ \
INDIR_Y_ADDR(address); \
value = mem_read(address); \
}
#define INDIR_Y_BYTE(value) \
{ \
/*IMMEDIATE_BYTE(btemp); \
temp = zp_address(btemp) + Y; \
CHECK_INDEX_OVERFLOW(temp, Y); \
value = mem_read(temp);*/ \
INDIR_Y(temp, value); \
}
#define JUMP(address) PC = bank_readaddress((address))
/*
** Interrupt macros
*/
#define NMI() \
{ \
PUSH(PC >> 8); \
PUSH(PC & 0xFF); \
CLEAR_FLAG(B_FLAG); \
PUSH(P); \
SET_FLAG(I_FLAG); \
JUMP(NMI_VECTOR); \
int_pending &= ~NMI_MASK; \
ADD_CYCLES(INT_CYCLES); \
}
#define IRQ() \
{ \
PUSH(PC >> 8); \
PUSH(PC & 0xFF); \
CLEAR_FLAG(B_FLAG); \
PUSH(P); \
SET_FLAG(I_FLAG); \
JUMP(IRQ_VECTOR); \
int_pending &= ~IRQ_MASK; \
ADD_CYCLES(INT_CYCLES); \
}
/*
** Instruction macros
*/
/* Warning! NES CPU has no decimal mode, so by default this does no BCD! */
#ifdef NES6502_DECIMAL
#define ADC(cycles, read_func) \
{ \
read_func(data); \
if (P & D_FLAG) \
{ \
temp = (A & 0x0F) + (data & 0x0F) + (P & C_FLAG); \
if (temp >= 10) \
temp = (temp - 10) | 0x10; \
temp += (A & 0xF0) + (data & 0xF0); \
TEST_AND_FLAG(0 == ((A + data + (P & C_FLAG)) & 0xFF), Z_FLAG); \
TEST_AND_FLAG(temp & 0x80, N_FLAG); \
TEST_AND_FLAG(((~(A ^ data)) & (A ^ temp) & 0x80), V_FLAG); \
if (temp > 0x9F) \
temp += 0x60; \
TEST_AND_FLAG(temp > 0xFF, C_FLAG); \
A = (uint8) temp; \
} \
else \
{ \
temp = A + data + (P & C_FLAG); \
/* Set C on carry */ \
TEST_AND_FLAG(temp > 0xFF, C_FLAG); \
/* Set V on overflow */ \
TEST_AND_FLAG(((~(A ^ data)) & (A ^ temp) & 0x80), V_FLAG); \
A = (uint8) temp; \
SET_NZ_FLAGS(A); \
}\
ADD_CYCLES(cycles); \
}
#else
#define ADC(cycles, read_func) \
{ \
read_func(data); \
temp = A + data + (P & C_FLAG); \
/* Set C on carry */ \
TEST_AND_FLAG(temp > 0xFF, C_FLAG); \
/* Set V on overflow */ \
TEST_AND_FLAG(((~(A ^ data)) & (A ^ temp) & 0x80), V_FLAG); \
A = (uint8) temp; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
#endif /* NES6502_DECIMAL */
/* undocumented */
#define ANC(cycles, read_func) \
{ \
read_func(data); \
A &= data; \
SET_NZ_FLAGS(A); \
TEST_AND_FLAG(P & N_FLAG, C_FLAG); \
ADD_CYCLES(cycles); \
}
#define AND(cycles, read_func) \
{ \
read_func(data); \
A &= data; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
/* undocumented */
#define ANE(cycles, read_func) \
{ \
read_func(data); \
A = (A | 0xEE) & X & data; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
/* undocumented */
#ifdef NES6502_DECIMAL
#define ARR(cycles, read_func) \
{ \
read_func(data); \
data &= A; \
if (P & D_FLAG) \
{ \
temp = (data >> 1) | ((P & C_FLAG) << 7); \
SET_NZ_FLAGS(temp); \
TEST_AND_FLAG((temp ^ data) & 0x40, V_FLAG); \
if (((data & 0x0F) + (data & 0x01)) > 5) \
temp = (temp & 0xF0) | ((temp + 0x6) & 0x0F); \
if (((data & 0xF0) + (data & 0x10)) > 0x50) \
{ \
temp = (temp & 0x0F) | ((temp + 0x60) & 0xF0); \
SET_FLAG(C_FLAG); \
} \
else \
CLEAR_FLAG(C_FLAG); \
A = (uint8) temp; \
} \
else \
{ \
A = (data >> 1) | ((P & C_FLAG) << 7); \
SET_NZ_FLAGS(A); \
TEST_AND_FLAG(A & 0x40, C_FLAG); \
TEST_AND_FLAG(((A >> 6) ^ (A >> 5)) & 1, V_FLAG); \
}\
ADD_CYCLES(cycles); \
}
#else
#define ARR(cycles, read_func) \
{ \
read_func(data); \
data &= A; \
A = (data >> 1) | ((P & C_FLAG) << 7); \
SET_NZ_FLAGS(A); \
TEST_AND_FLAG(A & 0x40, C_FLAG); \
TEST_AND_FLAG((A >> 6) ^ (A >> 5), V_FLAG); \
ADD_CYCLES(cycles); \
}
#endif /* NES6502_DECIMAL */
#define ASL(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
TEST_AND_FLAG(data & 0x80, C_FLAG); \
data <<= 1; \
write_func(addr, data); \
SET_NZ_FLAGS(data); \
ADD_CYCLES(cycles); \
}
#define ASL_A() \
{ \
TEST_AND_FLAG(A & 0x80, C_FLAG); \
A <<= 1; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(2); \
}
/* undocumented */
#define ASR(cycles, read_func) \
{ \
read_func(data); \
data &= A; \
TEST_AND_FLAG(data & 0x01, C_FLAG); \
A = data >> 1; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
#define BCC() \
{ \
RELATIVE_JUMP((IS_FLAG_CLEAR(C_FLAG))); \
}
#define BCS() \
{ \
RELATIVE_JUMP((IS_FLAG_SET(C_FLAG))); \
}
#define BEQ() \
{ \
RELATIVE_JUMP((IS_FLAG_SET(Z_FLAG))); \
}
#define BIT(cycles, read_func) \
{ \
read_func(data); \
TEST_AND_FLAG(0 == (data & A), Z_FLAG);\
CLEAR_FLAG(N_FLAG | V_FLAG); \
/* move bit 7/6 of data into N/V flags */ \
SET_FLAG(data & (N_FLAG | V_FLAG)); \
ADD_CYCLES(cycles); \
}
#define BMI() \
{ \
RELATIVE_JUMP((IS_FLAG_SET(N_FLAG))); \
}
#define BNE() \
{ \
RELATIVE_JUMP((IS_FLAG_CLEAR(Z_FLAG))); \
}
#define BPL() \
{ \
RELATIVE_JUMP((IS_FLAG_CLEAR(N_FLAG))); \
}
/* Software interrupt type thang */
#define BRK() \
{ \
PC++; \
PUSH(PC >> 8); \
PUSH(PC & 0xFF); \
SET_FLAG(B_FLAG); \
PUSH(P); \
SET_FLAG(I_FLAG); \
JUMP(IRQ_VECTOR); \
ADD_CYCLES(7); \
}
#define BVC() \
{ \
RELATIVE_JUMP((IS_FLAG_CLEAR(V_FLAG))); \
}
#define BVS() \
{ \
RELATIVE_JUMP((IS_FLAG_SET(V_FLAG))); \
}
#define CLC() \
{ \
CLEAR_FLAG(C_FLAG); \
ADD_CYCLES(2); \
}
#define CLD() \
{ \
CLEAR_FLAG(D_FLAG); \
ADD_CYCLES(2); \
}
#define CLI() \
{ \
CLEAR_FLAG(I_FLAG); \
ADD_CYCLES(2); \
}
#define CLV() \
{ \
CLEAR_FLAG(V_FLAG); \
ADD_CYCLES(2); \
}
/* TODO: ick! */
#define _COMPARE(reg, value) \
{ \
temp = (reg) - (value); \
/* C is clear when data > A */ \
TEST_AND_FLAG(0 == (temp & 0x8000), C_FLAG); \
SET_NZ_FLAGS((uint8) temp); /* handles Z flag */ \
}
#define CMP(cycles, read_func) \
{ \
read_func(data); \
_COMPARE(A, data); \
ADD_CYCLES(cycles); \
}
#define CPX(cycles, read_func) \
{ \
read_func(data); \
_COMPARE(X, data); \
ADD_CYCLES(cycles); \
}
#define CPY(cycles, read_func) \
{ \
read_func(data); \
_COMPARE(Y, data); \
ADD_CYCLES(cycles); \
}
/* undocumented */
#define DCP(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
data--; \
write_func(addr, data); \
CMP(cycles, NO_READ); \
}
#define DEC(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
data--; \
write_func(addr, data); \
SET_NZ_FLAGS(data); \
ADD_CYCLES(cycles); \
}
#define DEX() \
{ \
X--; \
SET_NZ_FLAGS(X); \
ADD_CYCLES(2); \
}
#define DEY() \
{ \
Y--; \
SET_NZ_FLAGS(Y); \
ADD_CYCLES(2); \
}
/* undocumented (double-NOP) */
#define DOP(cycles) \
{ \
PC++; \
ADD_CYCLES(cycles); \
}
#define EOR(cycles, read_func) \
{ \
read_func(data); \
A ^= data; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
#define INC(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
data++; \
write_func(addr, data); \
SET_NZ_FLAGS(data); \
ADD_CYCLES(cycles); \
}
#define INX() \
{ \
X++; \
SET_NZ_FLAGS(X); \
ADD_CYCLES(2); \
}
#define INY() \
{ \
Y++; \
SET_NZ_FLAGS(Y); \
ADD_CYCLES(2); \
}
/* undocumented */
#define ISB(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
data++; \
write_func(addr, data); \
SBC(cycles, NO_READ); \
}
#ifdef NES6502_TESTOPS
#define JAM() \
{ \
cpu_Jam(); \
}
#elif defined(NSF_PLAYER)
#define JAM() \
{ \
}
#else
#define JAM() \
{ \
char jambuf[20]; \
sprintf(jambuf, "JAM: PC=$%04X", PC); \
ASSERT_MSG(jambuf); \
ADD_CYCLES(2); \
}
#endif /* NES6502_TESTOPS */
#define JMP_INDIRECT() \
{ \
temp = bank_readaddress(PC); \
/* bug in crossing page boundaries */ \
if (0xFF == (uint8) temp) \
PC = (bank_readbyte(temp & ~0xFF) << 8) | bank_readbyte(temp); \
else \
JUMP(temp); \
ADD_CYCLES(5); \
}
#define JMP_ABSOLUTE() \
{ \
JUMP(PC); \
ADD_CYCLES(3); \
}
#define JSR() \
{ \
PC++; \
PUSH(PC >> 8); \
PUSH(PC & 0xFF); \
JUMP(PC - 1); \
ADD_CYCLES(6); \
}
/* undocumented */
#define LAS(cycles, read_func) \
{ \
read_func(data); \
A = X = S = (S & data); \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
/* undocumented */
#define LAX(cycles, read_func) \
{ \
read_func(A); \
X = A; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
#define LDA(cycles, read_func) \
{ \
read_func(A); \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
#define LDX(cycles, read_func) \
{ \
read_func(X); \
SET_NZ_FLAGS(X);\
ADD_CYCLES(cycles); \
}
#define LDY(cycles, read_func) \
{ \
read_func(Y); \
SET_NZ_FLAGS(Y);\
ADD_CYCLES(cycles); \
}
#define LSR(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
TEST_AND_FLAG(data & 0x01, C_FLAG); \
data >>= 1; \
write_func(addr, data); \
SET_NZ_FLAGS(data); \
ADD_CYCLES(cycles); \
}
#define LSR_A() \
{ \
TEST_AND_FLAG(A & 0x01, C_FLAG); \
A >>= 1; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(2); \
}
/* undocumented */
#define LXA(cycles, read_func) \
{ \
read_func(data); \
A = X = ((A | 0xEE) & data); \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
#define NOP() \
{ \
ADD_CYCLES(2); \
}
#define ORA(cycles, read_func) \
{ \
read_func(data); \
A |= data; \
SET_NZ_FLAGS(A);\
ADD_CYCLES(cycles); \
}
#define PHA() \
{ \
PUSH(A); \
ADD_CYCLES(3); \
}
#define PHP() \
{ \
/* B flag is pushed on stack as well */ \
PUSH((P | B_FLAG)); \
ADD_CYCLES(3); \
}
#define PLA() \
{ \
A = PULL(); \
SET_NZ_FLAGS(A); \
ADD_CYCLES(4); \
}
#define PLP() \
{ \
P = PULL(); \
SET_FLAG(R_FLAG); /* ensure reserved flag is set */ \
ADD_CYCLES(4); \
}
/* undocumented */
#define RLA(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
if (P & C_FLAG) \
{ \
TEST_AND_FLAG(data & 0x80, C_FLAG); \
data = (data << 1) | 1; \
} \
else \
{ \
TEST_AND_FLAG(data & 0x80, C_FLAG); \
data <<= 1; \
} \
write_func(addr, data); \
A &= data; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
/* 9-bit rotation (carry flag used for rollover) */
#define ROL(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
if (P & C_FLAG) \
{ \
TEST_AND_FLAG(data & 0x80, C_FLAG); \
data = (data << 1) | 1; \
} \
else \
{ \
TEST_AND_FLAG(data & 0x80, C_FLAG); \
data <<= 1; \
} \
write_func(addr, data); \
SET_NZ_FLAGS(data); \
ADD_CYCLES(cycles); \
}
#define ROL_A() \
{ \
if (P & C_FLAG) \
{ \
TEST_AND_FLAG(A & 0x80, C_FLAG); \
A = (A << 1) | 1; \
} \
else \
{ \
TEST_AND_FLAG(A & 0x80, C_FLAG); \
A <<= 1; \
} \
SET_NZ_FLAGS(A); \
ADD_CYCLES(2); \
}
#define ROR(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
if (P & C_FLAG) \
{ \
TEST_AND_FLAG(data & 1, C_FLAG); \
data = (data >> 1) | 0x80; \
} \
else \
{ \
TEST_AND_FLAG(data & 1, C_FLAG); \
data >>= 1; \
} \
write_func(addr, data); \
SET_NZ_FLAGS(data); \
ADD_CYCLES(cycles); \
}
#define ROR_A() \
{ \
if (P & C_FLAG) \
{ \
TEST_AND_FLAG(A & 1, C_FLAG); \
A = (A >> 1) | 0x80; \
} \
else \
{ \
TEST_AND_FLAG(A & 1, C_FLAG); \
A >>= 1; \
} \
SET_NZ_FLAGS(A); \
ADD_CYCLES(2); \
}
/* undocumented */
#define RRA(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
if (P & C_FLAG) \
{ \
TEST_AND_FLAG(data & 1, C_FLAG); \
data = (data >> 1) | 0x80; \
} \
else \
{ \
TEST_AND_FLAG(data & 1, C_FLAG); \
data >>= 1; \
} \
write_func(addr, data); \
ADC(cycles, NO_READ); \
}
#define RTI() \
{ \
P = PULL(); \
SET_FLAG(R_FLAG); /* ensure reserved flag is set */ \
PC = PULL(); \
PC |= PULL() << 8; \
ADD_CYCLES(6); \
}
#define RTS() \
{ \
PC = PULL(); \
PC = (PC | (PULL() << 8)) + 1; \
ADD_CYCLES(6); \
}
/* undocumented */
#define SAX(cycles, read_func, write_func, addr) \
{ \
read_func(addr); \
data = A & X; \
write_func(addr, data); \
ADD_CYCLES(cycles); \
}
/* Warning! NES CPU has no decimal mode, so by default this does no BCD! */
#ifdef NES6502_DECIMAL
#define SBC(cycles, read_func) \
{ \
read_func(data); \
/* NOT(C) is considered borrow */ \
temp = A - data - ((P & C_FLAG) ^ C_FLAG); \
if (P & D_FLAG) \
{ \
uint8 al, ah; \
al = (A & 0x0F) - (data & 0x0F) - ((P & C_FLAG) ^ C_FLAG); \
ah = (A >> 4) - (data >> 4); \
if (al & 0x10) \
{ \
al -= 6; \
ah--; \
} \
if (ah & 0x10) \
ah -= 6; \
TEST_AND_FLAG(temp < 0x100, C_FLAG); \
TEST_AND_FLAG(((A ^ temp) & 0x80) && ((A ^ data) & 0x80), V_FLAG); \
SET_NZ_FLAGS(temp & 0xFF); \
A = (ah << 4) | (al & 0x0F); \
} \
else \
{ \
TEST_AND_FLAG(((A ^ temp) & 0x80) && ((A ^ data) & 0x80), V_FLAG); \
TEST_AND_FLAG(temp < 0x100, C_FLAG); \
A = (uint8) temp; \
SET_NZ_FLAGS(A & 0xFF); \
} \
ADD_CYCLES(cycles); \
}
#else
#define SBC(cycles, read_func) \
{ \
read_func(data); \
temp = A - data - ((P & C_FLAG) ^ C_FLAG); \
TEST_AND_FLAG(((A ^ data) & (A ^ temp) & 0x80), V_FLAG); \
TEST_AND_FLAG(temp < 0x100, C_FLAG); \
A = (uint8) temp; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
#endif /* NES6502_DECIMAL */
/* undocumented */
#define SBX(cycles, read_func) \
{ \
read_func(data); \
temp = (A & X) - data; \
TEST_AND_FLAG(temp < 0x100, C_FLAG); \
X = temp & 0xFF; \
SET_NZ_FLAGS(X); \
ADD_CYCLES(cycles); \
}
#define SEC() \
{ \
SET_FLAG(C_FLAG); \
ADD_CYCLES(2); \
}
#define SED() \
{ \
SET_FLAG(D_FLAG); \
ADD_CYCLES(2); \
}
#define SEI() \
{ \
SET_FLAG(I_FLAG); \
ADD_CYCLES(2); \
}
/* undocumented */
#define SHA(cycles, read_func, write_func, addr) \
{ \
read_func(addr); \
data = A & X & ((uint8) ((addr >> 8) + 1)); \
write_func(addr, data); \
ADD_CYCLES(cycles); \
}
/* undocumented */
#define SHS(cycles, read_func, write_func, addr) \
{ \
read_func(addr); \
S = A & X; \
data = S & ((uint8) ((addr >> 8) + 1)); \
write_func(addr, data); \
ADD_CYCLES(cycles); \
}
/* undocumented */
#define SHX(cycles, read_func, write_func, addr) \
{ \
read_func(addr); \
data = X & ((uint8) ((addr >> 8) + 1)); \
write_func(addr, data); \
ADD_CYCLES(cycles); \
}
/* undocumented */
#define SHY(cycles, read_func, write_func, addr) \
{ \
read_func(addr); \
data = Y & ((uint8) ((addr >> 8 ) + 1)); \
write_func(addr, data); \
ADD_CYCLES(cycles); \
}
/* undocumented */
#define SLO(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
TEST_AND_FLAG(data & 0x80, C_FLAG); \
data <<= 1; \
write_func(addr, data); \
A |= data; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
/* unoffical */
#define SRE(cycles, read_func, write_func, addr) \
{ \
read_func(addr, data); \
TEST_AND_FLAG(data & 1, C_FLAG); \
data >>= 1; \
write_func(addr, data); \
A ^= data; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(cycles); \
}
#define STA(cycles, read_func, write_func, addr) \
{ \
read_func(addr); \
write_func(addr, A); \
ADD_CYCLES(cycles); \
}
#define STX(cycles, read_func, write_func, addr) \
{ \
read_func(addr); \
write_func(addr, X); \
ADD_CYCLES(cycles); \
}
#define STY(cycles, read_func, write_func, addr) \
{ \
read_func(addr); \
write_func(addr, Y); \
ADD_CYCLES(cycles); \
}
#define TAX() \
{ \
X = A; \
SET_NZ_FLAGS(X);\
ADD_CYCLES(2); \
}
#define TAY() \
{ \
Y = A; \
SET_NZ_FLAGS(Y);\
ADD_CYCLES(2); \
}
/* undocumented (triple-NOP) */
#define TOP() \
{ \
PC += 2; \
ADD_CYCLES(4); \
}
#define TSX() \
{ \
X = S; \
SET_NZ_FLAGS(X);\
ADD_CYCLES(2); \
}
#define TXA() \
{ \
A = X; \
SET_NZ_FLAGS(A);\
ADD_CYCLES(2); \
}
#define TXS() \
{ \
S = X; \
ADD_CYCLES(2); \
}
#define TYA() \
{ \
A = Y; \
SET_NZ_FLAGS(A); \
ADD_CYCLES(2); \
}
/*
** Stack and data fetching macros
*/
/* Set/clear/test bits in the flags register */
#define SET_FLAG(mask) P |= (mask)
#define CLEAR_FLAG(mask) P &= ~(mask)
#define IS_FLAG_SET(mask) (P & (mask))
#define IS_FLAG_CLEAR(mask) (0 == IS_FLAG_SET((mask)))
#define TEST_AND_FLAG(test, mask) \
{ \
if ((test)) \
SET_FLAG((mask)); \
else \
CLEAR_FLAG((mask)); \
}
/*
** flag register helper macros
*/
/* register push/pull */
#define PUSH(value) stack_page[S--] = (uint8) (value)
#define PULL() stack_page[++S]
/* Sets the Z and N flags based on given data, taken from precomputed table */
#define SET_NZ_FLAGS(value) P &= ~(N_FLAG | Z_FLAG); \
P |= flag_table[(value)]
#define GET_GLOBAL_REGS() \
{ \
PC = reg_PC; \
A = reg_A; \
X = reg_X; \
Y = reg_Y; \
P = reg_P; \
S = reg_S; \
}
#define SET_LOCAL_REGS() \
{ \
reg_PC = PC; \
reg_A = A; \
reg_X = X; \
reg_Y = Y; \
reg_P = P; \
reg_S = S; \
}
/* static data */
static nes6502_memread *pmem_read, *pmr;
static nes6502_memwrite *pmem_write, *pmw;
/* lookup table for N/Z flags */
static uint8 flag_table[256];
/* internal critical CPU vars */
static uint32 reg_PC;
static uint8 reg_A, reg_P, reg_X, reg_Y, reg_S;
static uint8 int_pending;
static int dma_cycles;
/* execution cycle count (can be reset by user) */
static uint32 total_cycles = 0;
/* memory region pointers */
static uint8 *nes6502_banks[NES6502_NUMBANKS];
static uint8 *ram = NULL;
static uint8 *stack_page = NULL;
/*
** Zero-page helper macros
*/
#define ZP_READ(addr) ram[(addr)]
#define ZP_WRITE(addr, value) ram[(addr)] = (uint8) (value)
INLINE uint8
bank_readbyte (register uint32 address)
{
ASSERT (nes6502_banks[address >> NES6502_BANKSHIFT]);
return nes6502_banks[address >> NES6502_BANKSHIFT][address &
NES6502_BANKMASK];
}
INLINE void
bank_writebyte (register uint32 address, register uint8 value)
{
ASSERT (nes6502_banks[address >> NES6502_BANKSHIFT]);
nes6502_banks[address >> NES6502_BANKSHIFT][address & NES6502_BANKMASK] =
value;
}
INLINE uint32
zp_address (register uint8 address)
{
#ifdef HOST_LITTLE_ENDIAN
/* TODO: this fails if src address is $xFFF */
/* TODO: this fails if host architecture doesn't support byte alignment */
return (uint32) (*(uint16 *) (ram + address));
#else
#ifdef TARGET_CPU_PPC
return __lhbrx (ram, address);
#else
uint32 x = (uint32) * (uint16 *) (ram + address);
return (x << 8) | (x >> 8);
#endif /* TARGET_CPU_PPC */
#endif /* HOST_LITTLE_ENDIAN */
}
INLINE uint32
bank_readaddress (register uint32 address)
{
#ifdef HOST_LITTLE_ENDIAN
/* TODO: this fails if src address is $xFFF */
/* TODO: this fails if host architecture doesn't support byte alignment */
return (uint32) (*(uint16 *) (nes6502_banks[address >> NES6502_BANKSHIFT] +
(address & NES6502_BANKMASK)));
#else
#ifdef TARGET_CPU_PPC
return __lhbrx (nes6502_banks[address >> NES6502_BANKSHIFT],
address & NES6502_BANKMASK);
#else
uint32 x =
(uint32) * (uint16 *) (nes6502_banks[address >> NES6502_BANKSHIFT] +
(address & NES6502_BANKMASK));
return (x << 8) | (x >> 8);
#endif /* TARGET_CPU_PPC */
#endif /* HOST_LITTLE_ENDIAN */
}
/* read a byte of 6502 memory */
static uint8
mem_read (uint32 address)
{
/* TODO: following cases are N2A03-specific */
/* RAM */
if (address < 0x800)
return ram[address];
/* always paged memory */
/* else if (address >= 0x6000) */
else if (address >= 0x8000)
return bank_readbyte (address);
/* check memory range handlers */
else {
for (pmr = pmem_read; pmr->min_range != 0xFFFFFFFF; pmr++) {
if ((address >= pmr->min_range) && (address <= pmr->max_range))
return pmr->read_func (address);
}
}
/* return paged memory */
return bank_readbyte (address);
}
/* write a byte of data to 6502 memory */
static void
mem_write (uint32 address, uint8 value)
{
/* RAM */
if (address < 0x800) {
ram[address] = value;
return;
}
/* check memory range handlers */
else {
for (pmw = pmem_write; pmw->min_range != 0xFFFFFFFF; pmw++) {
if ((address >= pmw->min_range) && (address <= pmw->max_range)) {
pmw->write_func (address, value);
return;
}
}
}
/* write to paged memory */
bank_writebyte (address, value);
}
/* set the current context */
void
nes6502_setcontext (nes6502_context * cpu)
{
int loop;
ASSERT (cpu);
/* Set the page pointers */
for (loop = 0; loop < NES6502_NUMBANKS; loop++)
nes6502_banks[loop] = cpu->mem_page[loop];
ram = nes6502_banks[0]; /* quicker zero-page/RAM references */
stack_page = ram + STACK_OFFSET;
pmem_read = cpu->read_handler;
pmem_write = cpu->write_handler;
reg_PC = cpu->pc_reg;
reg_A = cpu->a_reg;
reg_P = cpu->p_reg;
reg_X = cpu->x_reg;
reg_Y = cpu->y_reg;
reg_S = cpu->s_reg;
int_pending = cpu->int_pending;
dma_cycles = cpu->dma_cycles;
}
/* get the current context */
void
nes6502_getcontext (nes6502_context * cpu)
{
int loop;
/* Set the page pointers */
for (loop = 0; loop < NES6502_NUMBANKS; loop++)
cpu->mem_page[loop] = nes6502_banks[loop];
cpu->read_handler = pmem_read;
cpu->write_handler = pmem_write;
cpu->pc_reg = reg_PC;
cpu->a_reg = reg_A;
cpu->p_reg = reg_P;
cpu->x_reg = reg_X;
cpu->y_reg = reg_Y;
cpu->s_reg = reg_S;
cpu->int_pending = int_pending;
cpu->dma_cycles = dma_cycles;
}
/* DMA a byte of data from ROM */
uint8
nes6502_getbyte (uint32 address)
{
return bank_readbyte (address);
}
/* get number of elapsed cycles */
uint32
nes6502_getcycles (boolean reset_flag)
{
uint32 cycles = total_cycles;
if (reset_flag)
total_cycles = 0;
return cycles;
}
/* Execute instructions until count expires
**
** Returns the number of cycles *actually* executed
** (note that this can be from 0-6 cycles more than you wanted)
*/
int
nes6502_execute (int remaining_cycles)
{
int instruction_cycles, old_cycles = total_cycles;
uint32 temp, addr; /* for macros */
uint32 PC;
uint8 A, X, Y, P, S;
uint8 opcode, data;
uint8 btemp, baddr; /* for macros */
GET_GLOBAL_REGS ();
/* Continue until we run out of cycles */
while (remaining_cycles > 0) {
instruction_cycles = 0;
/* check for DMA cycle burning */
if (dma_cycles) {
if (remaining_cycles <= dma_cycles) {
dma_cycles -= remaining_cycles;
total_cycles += remaining_cycles;
goto _execute_done;
} else {
remaining_cycles -= dma_cycles;
total_cycles += dma_cycles;
dma_cycles = 0;
}
}
if (int_pending) {
/* NMI has highest priority */
if (int_pending & NMI_MASK) {
NMI ();
}
/* IRQ has lowest priority */
else { /* if (int_pending & IRQ_MASK) */
if (IS_FLAG_CLEAR (I_FLAG))
IRQ ();
}
}
/* Fetch instruction */
/* nes6502_disasm(PC, P, A, X, Y, S); */
opcode = bank_readbyte (PC++);
/* Execute instruction */
switch (opcode) {
case 0x00: /* BRK */
BRK ();
break;
case 0x01: /* ORA ($nn,X) */
ORA (6, INDIR_X_BYTE);
break;
/* JAM */
case 0x02: /* JAM */
case 0x12: /* JAM */
case 0x22: /* JAM */
case 0x32: /* JAM */
case 0x42: /* JAM */
case 0x52: /* JAM */
case 0x62: /* JAM */
case 0x72: /* JAM */
case 0x92: /* JAM */
case 0xB2: /* JAM */
case 0xD2: /* JAM */
case 0xF2: /* JAM */
JAM ();
/* kill switch for CPU emulation */
goto _execute_done;
case 0x03: /* SLO ($nn,X) */
SLO (8, INDIR_X, mem_write, addr);
break;
case 0x04: /* NOP $nn */
case 0x44: /* NOP $nn */
case 0x64: /* NOP $nn */
DOP (3);
break;
case 0x05: /* ORA $nn */
ORA (3, ZERO_PAGE_BYTE);
break;
case 0x06: /* ASL $nn */
ASL (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0x07: /* SLO $nn */
SLO (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0x08: /* PHP */
PHP ();
break;
case 0x09: /* ORA #$nn */
ORA (2, IMMEDIATE_BYTE);
break;
case 0x0A: /* ASL A */
ASL_A ();
break;
case 0x0B: /* ANC #$nn */
ANC (2, IMMEDIATE_BYTE);
break;
case 0x0C: /* NOP $nnnn */
TOP ();
break;
case 0x0D: /* ORA $nnnn */
ORA (4, ABSOLUTE_BYTE);
break;
case 0x0E: /* ASL $nnnn */
ASL (6, ABSOLUTE, mem_write, addr);
break;
case 0x0F: /* SLO $nnnn */
SLO (6, ABSOLUTE, mem_write, addr);
break;
case 0x10: /* BPL $nnnn */
BPL ();
break;
case 0x11: /* ORA ($nn),Y */
ORA (5, INDIR_Y_BYTE);
break;
case 0x13: /* SLO ($nn),Y */
SLO (8, INDIR_Y, mem_write, addr);
break;
case 0x14: /* NOP $nn,X */
case 0x34: /* NOP */
case 0x54: /* NOP $nn,X */
case 0x74: /* NOP $nn,X */
case 0xD4: /* NOP $nn,X */
case 0xF4: /* NOP ($nn,X) */
DOP (4);
break;
case 0x15: /* ORA $nn,X */
ORA (4, ZP_IND_X_BYTE);
break;
case 0x16: /* ASL $nn,X */
ASL (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0x17: /* SLO $nn,X */
SLO (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0x18: /* CLC */
CLC ();
break;
case 0x19: /* ORA $nnnn,Y */
ORA (4, ABS_IND_Y_BYTE);
break;
case 0x1A: /* NOP */
case 0x3A: /* NOP */
case 0x5A: /* NOP */
case 0x7A: /* NOP */
case 0xDA: /* NOP */
case 0xFA: /* NOP */
NOP ();
break;
case 0x1B: /* SLO $nnnn,Y */
SLO (7, ABS_IND_Y, mem_write, addr);
break;
case 0x1C: /* NOP $nnnn,X */
case 0x3C: /* NOP $nnnn,X */
case 0x5C: /* NOP $nnnn,X */
case 0x7C: /* NOP $nnnn,X */
case 0xDC: /* NOP $nnnn,X */
case 0xFC: /* NOP $nnnn,X */
TOP ();
break;
case 0x1D: /* ORA $nnnn,X */
ORA (4, ABS_IND_X_BYTE);
break;
case 0x1E: /* ASL $nnnn,X */
ASL (7, ABS_IND_X, mem_write, addr);
break;
case 0x1F: /* SLO $nnnn,X */
SLO (7, ABS_IND_X, mem_write, addr);
break;
case 0x20: /* JSR $nnnn */
JSR ();
break;
case 0x21: /* AND ($nn,X) */
AND (6, INDIR_X_BYTE);
break;
case 0x23: /* RLA ($nn,X) */
RLA (8, INDIR_X, mem_write, addr);
break;
case 0x24: /* BIT $nn */
BIT (3, ZERO_PAGE_BYTE);
break;
case 0x25: /* AND $nn */
AND (3, ZERO_PAGE_BYTE);
break;
case 0x26: /* ROL $nn */
ROL (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0x27: /* RLA $nn */
RLA (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0x28: /* PLP */
PLP ();
break;
case 0x29: /* AND #$nn */
AND (2, IMMEDIATE_BYTE);
break;
case 0x2A: /* ROL A */
ROL_A ();
break;
case 0x2B: /* ANC #$nn */
ANC (2, IMMEDIATE_BYTE);
break;
case 0x2C: /* BIT $nnnn */
BIT (4, ABSOLUTE_BYTE);
break;
case 0x2D: /* AND $nnnn */
AND (4, ABSOLUTE_BYTE);
break;
case 0x2E: /* ROL $nnnn */
ROL (6, ABSOLUTE, mem_write, addr);
break;
case 0x2F: /* RLA $nnnn */
RLA (6, ABSOLUTE, mem_write, addr);
break;
case 0x30: /* BMI $nnnn */
BMI ();
break;
case 0x31: /* AND ($nn),Y */
AND (5, INDIR_Y_BYTE);
break;
case 0x33: /* RLA ($nn),Y */
RLA (8, INDIR_Y, mem_write, addr);
break;
case 0x35: /* AND $nn,X */
AND (4, ZP_IND_X_BYTE);
break;
case 0x36: /* ROL $nn,X */
ROL (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0x37: /* RLA $nn,X */
RLA (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0x38: /* SEC */
SEC ();
break;
case 0x39: /* AND $nnnn,Y */
AND (4, ABS_IND_Y_BYTE);
break;
case 0x3B: /* RLA $nnnn,Y */
RLA (7, ABS_IND_Y, mem_write, addr);
break;
case 0x3D: /* AND $nnnn,X */
AND (4, ABS_IND_X_BYTE);
break;
case 0x3E: /* ROL $nnnn,X */
ROL (7, ABS_IND_X, mem_write, addr);
break;
case 0x3F: /* RLA $nnnn,X */
RLA (7, ABS_IND_X, mem_write, addr);
break;
case 0x40: /* RTI */
RTI ();
break;
case 0x41: /* EOR ($nn,X) */
EOR (6, INDIR_X_BYTE);
break;
case 0x43: /* SRE ($nn,X) */
SRE (8, INDIR_X, mem_write, addr);
break;
case 0x45: /* EOR $nn */
EOR (3, ZERO_PAGE_BYTE);
break;
case 0x46: /* LSR $nn */
LSR (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0x47: /* SRE $nn */
SRE (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0x48: /* PHA */
PHA ();
break;
case 0x49: /* EOR #$nn */
EOR (2, IMMEDIATE_BYTE);
break;
case 0x4A: /* LSR A */
LSR_A ();
break;
case 0x4B: /* ASR #$nn */
ASR (2, IMMEDIATE_BYTE);
break;
case 0x4C: /* JMP $nnnn */
JMP_ABSOLUTE ();
break;
case 0x4D: /* EOR $nnnn */
EOR (4, ABSOLUTE_BYTE);
break;
case 0x4E: /* LSR $nnnn */
LSR (6, ABSOLUTE, mem_write, addr);
break;
case 0x4F: /* SRE $nnnn */
SRE (6, ABSOLUTE, mem_write, addr);
break;
case 0x50: /* BVC $nnnn */
BVC ();
break;
case 0x51: /* EOR ($nn),Y */
EOR (5, INDIR_Y_BYTE);
break;
case 0x53: /* SRE ($nn),Y */
SRE (8, INDIR_Y, mem_write, addr);
break;
case 0x55: /* EOR $nn,X */
EOR (4, ZP_IND_X_BYTE);
break;
case 0x56: /* LSR $nn,X */
LSR (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0x57: /* SRE $nn,X */
SRE (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0x58: /* CLI */
CLI ();
break;
case 0x59: /* EOR $nnnn,Y */
EOR (4, ABS_IND_Y_BYTE);
break;
case 0x5B: /* SRE $nnnn,Y */
SRE (7, ABS_IND_Y, mem_write, addr);
break;
case 0x5D: /* EOR $nnnn,X */
EOR (4, ABS_IND_X_BYTE);
break;
case 0x5E: /* LSR $nnnn,X */
LSR (7, ABS_IND_X, mem_write, addr);
break;
case 0x5F: /* SRE $nnnn,X */
SRE (7, ABS_IND_X, mem_write, addr);
break;
case 0x60: /* RTS */
RTS ();
break;
case 0x61: /* ADC ($nn,X) */
ADC (6, INDIR_X_BYTE);
break;
case 0x63: /* RRA ($nn,X) */
RRA (8, INDIR_X, mem_write, addr);
break;
case 0x65: /* ADC $nn */
ADC (3, ZERO_PAGE_BYTE);
break;
case 0x66: /* ROR $nn */
ROR (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0x67: /* RRA $nn */
RRA (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0x68: /* PLA */
PLA ();
break;
case 0x69: /* ADC #$nn */
ADC (2, IMMEDIATE_BYTE);
break;
case 0x6A: /* ROR A */
ROR_A ();
break;
case 0x6B: /* ARR #$nn */
ARR (2, IMMEDIATE_BYTE);
break;
case 0x6C: /* JMP ($nnnn) */
JMP_INDIRECT ();
break;
case 0x6D: /* ADC $nnnn */
ADC (4, ABSOLUTE_BYTE);
break;
case 0x6E: /* ROR $nnnn */
ROR (6, ABSOLUTE, mem_write, addr);
break;
case 0x6F: /* RRA $nnnn */
RRA (6, ABSOLUTE, mem_write, addr);
break;
case 0x70: /* BVS $nnnn */
BVS ();
break;
case 0x71: /* ADC ($nn),Y */
ADC (5, INDIR_Y_BYTE);
break;
case 0x73: /* RRA ($nn),Y */
RRA (8, INDIR_Y, mem_write, addr);
break;
case 0x75: /* ADC $nn,X */
ADC (4, ZP_IND_X_BYTE);
break;
case 0x76: /* ROR $nn,X */
ROR (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0x77: /* RRA $nn,X */
RRA (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0x78: /* SEI */
SEI ();
break;
case 0x79: /* ADC $nnnn,Y */
ADC (4, ABS_IND_Y_BYTE);
break;
case 0x7B: /* RRA $nnnn,Y */
RRA (7, ABS_IND_Y, mem_write, addr);
break;
case 0x7D: /* ADC $nnnn,X */
ADC (4, ABS_IND_X_BYTE);
break;
case 0x7E: /* ROR $nnnn,X */
ROR (7, ABS_IND_X, mem_write, addr);
break;
case 0x7F: /* RRA $nnnn,X */
RRA (7, ABS_IND_X, mem_write, addr);
break;
case 0x80: /* NOP #$nn */
case 0x82: /* NOP #$nn */
case 0x89: /* NOP #$nn */
case 0xC2: /* NOP #$nn */
case 0xE2: /* NOP #$nn */
DOP (2);
break;
case 0x81: /* STA ($nn,X) */
STA (6, INDIR_X_ADDR, mem_write, addr);
break;
case 0x83: /* SAX ($nn,X) */
SAX (6, INDIR_X_ADDR, mem_write, addr);
break;
case 0x84: /* STY $nn */
STY (3, ZERO_PAGE_ADDR, ZP_WRITE, baddr);
break;
case 0x85: /* STA $nn */
STA (3, ZERO_PAGE_ADDR, ZP_WRITE, baddr);
break;
case 0x86: /* STX $nn */
STX (3, ZERO_PAGE_ADDR, ZP_WRITE, baddr);
break;
case 0x87: /* SAX $nn */
SAX (3, ZERO_PAGE_ADDR, ZP_WRITE, baddr);
break;
case 0x88: /* DEY */
DEY ();
break;
case 0x8A: /* TXA */
TXA ();
break;
case 0x8B: /* ANE #$nn */
ANE (2, IMMEDIATE_BYTE);
break;
case 0x8C: /* STY $nnnn */
STY (4, ABSOLUTE_ADDR, mem_write, addr);
break;
case 0x8D: /* STA $nnnn */
STA (4, ABSOLUTE_ADDR, mem_write, addr);
break;
case 0x8E: /* STX $nnnn */
STX (4, ABSOLUTE_ADDR, mem_write, addr);
break;
case 0x8F: /* SAX $nnnn */
SAX (4, ABSOLUTE_ADDR, mem_write, addr);
break;
case 0x90: /* BCC $nnnn */
BCC ();
break;
case 0x91: /* STA ($nn),Y */
STA (6, INDIR_Y_ADDR, mem_write, addr);
break;
case 0x93: /* SHA ($nn),Y */
SHA (6, INDIR_Y_ADDR, mem_write, addr);
break;
case 0x94: /* STY $nn,X */
STY (4, ZP_IND_X_ADDR, ZP_WRITE, baddr);
break;
case 0x95: /* STA $nn,X */
STA (4, ZP_IND_X_ADDR, ZP_WRITE, baddr);
break;
case 0x96: /* STX $nn,Y */
STX (4, ZP_IND_Y_ADDR, ZP_WRITE, baddr);
break;
case 0x97: /* SAX $nn,Y */
SAX (4, ZP_IND_Y_ADDR, ZP_WRITE, baddr);
break;
case 0x98: /* TYA */
TYA ();
break;
case 0x99: /* STA $nnnn,Y */
STA (5, ABS_IND_Y_ADDR, mem_write, addr);
break;
case 0x9A: /* TXS */
TXS ();
break;
case 0x9B: /* SHS $nnnn,Y */
SHS (5, ABS_IND_Y_ADDR, mem_write, addr);
break;
case 0x9C: /* SHY $nnnn,X */
SHY (5, ABS_IND_X_ADDR, mem_write, addr);
break;
case 0x9D: /* STA $nnnn,X */
STA (5, ABS_IND_X_ADDR, mem_write, addr);
break;
case 0x9E: /* SHX $nnnn,Y */
SHX (5, ABS_IND_Y_ADDR, mem_write, addr);
break;
case 0x9F: /* SHA $nnnn,Y */
SHA (5, ABS_IND_Y_ADDR, mem_write, addr);
break;
case 0xA0: /* LDY #$nn */
LDY (2, IMMEDIATE_BYTE);
break;
case 0xA1: /* LDA ($nn,X) */
LDA (6, INDIR_X_BYTE);
break;
case 0xA2: /* LDX #$nn */
LDX (2, IMMEDIATE_BYTE);
break;
case 0xA3: /* LAX ($nn,X) */
LAX (6, INDIR_X_BYTE);
break;
case 0xA4: /* LDY $nn */
LDY (3, ZERO_PAGE_BYTE);
break;
case 0xA5: /* LDA $nn */
LDA (3, ZERO_PAGE_BYTE);
break;
case 0xA6: /* LDX $nn */
LDX (3, ZERO_PAGE_BYTE);
break;
case 0xA7: /* LAX $nn */
LAX (3, ZERO_PAGE_BYTE);
break;
case 0xA8: /* TAY */
TAY ();
break;
case 0xA9: /* LDA #$nn */
LDA (2, IMMEDIATE_BYTE);
break;
case 0xAA: /* TAX */
TAX ();
break;
case 0xAB: /* LXA #$nn */
LXA (2, IMMEDIATE_BYTE);
break;
case 0xAC: /* LDY $nnnn */
LDY (4, ABSOLUTE_BYTE);
break;
case 0xAD: /* LDA $nnnn */
LDA (4, ABSOLUTE_BYTE);
break;
case 0xAE: /* LDX $nnnn */
LDX (4, ABSOLUTE_BYTE);
break;
case 0xAF: /* LAX $nnnn */
LAX (4, ABSOLUTE_BYTE);
break;
case 0xB0: /* BCS $nnnn */
BCS ();
break;
case 0xB1: /* LDA ($nn),Y */
LDA (5, INDIR_Y_BYTE);
break;
case 0xB3: /* LAX ($nn),Y */
LAX (5, INDIR_Y_BYTE);
break;
case 0xB4: /* LDY $nn,X */
LDY (4, ZP_IND_X_BYTE);
break;
case 0xB5: /* LDA $nn,X */
LDA (4, ZP_IND_X_BYTE);
break;
case 0xB6: /* LDX $nn,Y */
LDX (4, ZP_IND_Y_BYTE);
break;
case 0xB7: /* LAX $nn,Y */
LAX (4, ZP_IND_Y_BYTE);
break;
case 0xB8: /* CLV */
CLV ();
break;
case 0xB9: /* LDA $nnnn,Y */
LDA (4, ABS_IND_Y_BYTE);
break;
case 0xBA: /* TSX */
TSX ();
break;
case 0xBB: /* LAS $nnnn,Y */
LAS (4, ABS_IND_Y_BYTE);
break;
case 0xBC: /* LDY $nnnn,X */
LDY (4, ABS_IND_X_BYTE);
break;
case 0xBD: /* LDA $nnnn,X */
LDA (4, ABS_IND_X_BYTE);
break;
case 0xBE: /* LDX $nnnn,Y */
LDX (4, ABS_IND_Y_BYTE);
break;
case 0xBF: /* LAX $nnnn,Y */
LAX (4, ABS_IND_Y_BYTE);
break;
case 0xC0: /* CPY #$nn */
CPY (2, IMMEDIATE_BYTE);
break;
case 0xC1: /* CMP ($nn,X) */
CMP (6, INDIR_X_BYTE);
break;
case 0xC3: /* DCP ($nn,X) */
DCP (8, INDIR_X, mem_write, addr);
break;
case 0xC4: /* CPY $nn */
CPY (3, ZERO_PAGE_BYTE);
break;
case 0xC5: /* CMP $nn */
CMP (3, ZERO_PAGE_BYTE);
break;
case 0xC6: /* DEC $nn */
DEC (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0xC7: /* DCP $nn */
DCP (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0xC8: /* INY */
INY ();
break;
case 0xC9: /* CMP #$nn */
CMP (2, IMMEDIATE_BYTE);
break;
case 0xCA: /* DEX */
DEX ();
break;
case 0xCB: /* SBX #$nn */
SBX (2, IMMEDIATE_BYTE);
break;
case 0xCC: /* CPY $nnnn */
CPY (4, ABSOLUTE_BYTE);
break;
case 0xCD: /* CMP $nnnn */
CMP (4, ABSOLUTE_BYTE);
break;
case 0xCE: /* DEC $nnnn */
DEC (6, ABSOLUTE, mem_write, addr);
break;
case 0xCF: /* DCP $nnnn */
DCP (6, ABSOLUTE, mem_write, addr);
break;
case 0xD0: /* BNE $nnnn */
BNE ();
break;
case 0xD1: /* CMP ($nn),Y */
CMP (5, INDIR_Y_BYTE);
break;
case 0xD3: /* DCP ($nn),Y */
DCP (8, INDIR_Y, mem_write, addr);
break;
case 0xD5: /* CMP $nn,X */
CMP (4, ZP_IND_X_BYTE);
break;
case 0xD6: /* DEC $nn,X */
DEC (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0xD7: /* DCP $nn,X */
DCP (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0xD8: /* CLD */
CLD ();
break;
case 0xD9: /* CMP $nnnn,Y */
CMP (4, ABS_IND_Y_BYTE);
break;
case 0xDB: /* DCP $nnnn,Y */
DCP (7, ABS_IND_Y, mem_write, addr);
break;
case 0xDD: /* CMP $nnnn,X */
CMP (4, ABS_IND_X_BYTE);
break;
case 0xDE: /* DEC $nnnn,X */
DEC (7, ABS_IND_X, mem_write, addr);
break;
case 0xDF: /* DCP $nnnn,X */
DCP (7, ABS_IND_X, mem_write, addr);
break;
case 0xE0: /* CPX #$nn */
CPX (2, IMMEDIATE_BYTE);
break;
case 0xE1: /* SBC ($nn,X) */
SBC (6, INDIR_X_BYTE);
break;
case 0xE3: /* ISB ($nn,X) */
ISB (8, INDIR_X, mem_write, addr);
break;
case 0xE4: /* CPX $nn */
CPX (3, ZERO_PAGE_BYTE);
break;
case 0xE5: /* SBC $nn */
SBC (3, ZERO_PAGE_BYTE);
break;
case 0xE6: /* INC $nn */
INC (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0xE7: /* ISB $nn */
ISB (5, ZERO_PAGE, ZP_WRITE, baddr);
break;
case 0xE8: /* INX */
INX ();
break;
case 0xE9: /* SBC #$nn */
case 0xEB: /* USBC #$nn */
SBC (2, IMMEDIATE_BYTE);
break;
case 0xEA: /* NOP */
NOP ();
break;
case 0xEC: /* CPX $nnnn */
CPX (4, ABSOLUTE_BYTE);
break;
case 0xED: /* SBC $nnnn */
SBC (4, ABSOLUTE_BYTE);
break;
case 0xEE: /* INC $nnnn */
INC (6, ABSOLUTE, mem_write, addr);
break;
case 0xEF: /* ISB $nnnn */
ISB (6, ABSOLUTE, mem_write, addr);
break;
case 0xF0: /* BEQ $nnnn */
BEQ ();
break;
case 0xF1: /* SBC ($nn),Y */
SBC (5, INDIR_Y_BYTE);
break;
case 0xF3: /* ISB ($nn),Y */
ISB (8, INDIR_Y, mem_write, addr);
break;
case 0xF5: /* SBC $nn,X */
SBC (4, ZP_IND_X_BYTE);
break;
case 0xF6: /* INC $nn,X */
INC (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0xF7: /* ISB $nn,X */
ISB (6, ZP_IND_X, ZP_WRITE, baddr);
break;
case 0xF8: /* SED */
SED ();
break;
case 0xF9: /* SBC $nnnn,Y */
SBC (4, ABS_IND_Y_BYTE);
break;
case 0xFB: /* ISB $nnnn,Y */
ISB (7, ABS_IND_Y, mem_write, addr);
break;
case 0xFD: /* SBC $nnnn,X */
SBC (4, ABS_IND_X_BYTE);
break;
case 0xFE: /* INC $nnnn,X */
INC (7, ABS_IND_X, mem_write, addr);
break;
case 0xFF: /* ISB $nnnn,X */
ISB (7, ABS_IND_X, mem_write, addr);
break;
}
/* Calculate remaining/elapsed clock cycles */
remaining_cycles -= instruction_cycles;
total_cycles += instruction_cycles;
}
_execute_done:
/* restore local copy of regs */
SET_LOCAL_REGS ();
/* Return our actual amount of executed cycles */
return (total_cycles - old_cycles);
}
/* Initialize tables, etc. */
void
nes6502_init (void)
{
int index;
/* Build the N / Z flag lookup table */
flag_table[0] = Z_FLAG;
for (index = 1; index < 256; index++)
flag_table[index] = (index & 0x80) ? N_FLAG : 0;
reg_A = reg_X = reg_Y = 0;
reg_S = 0xFF; /* Stack grows down */
}
/* Issue a CPU Reset */
void
nes6502_reset (void)
{
reg_P = Z_FLAG | R_FLAG | I_FLAG; /* Reserved bit always 1 */
int_pending = dma_cycles = 0; /* No pending interrupts */
reg_PC = bank_readaddress (RESET_VECTOR); /* Fetch reset vector */
/* TODO: 6 cycles for RESET? */
}
/* Non-maskable interrupt */
void
nes6502_nmi (void)
{
int_pending |= NMI_MASK;
}
/* Interrupt request */
void
nes6502_irq (void)
{
int_pending |= IRQ_MASK;
}
/* Set dma period (in cycles) */
void
nes6502_setdma (int cycles)
{
dma_cycles += cycles;
}
/*
** $Log$
** Revision 1.1 2006/07/13 15:07:28 wtay
** Based on patches by: Johan Dahlin <johan at gnome dot org>
** Ronald Bultje <rbultje at ronald dot bitfreak dot net>
** * configure.ac:
** * gst/nsf/Makefile.am:
** * gst/nsf/dis6502.h:
** * gst/nsf/fds_snd.c:
** * gst/nsf/fds_snd.h:
** * gst/nsf/fmopl.c:
** * gst/nsf/fmopl.h:
** * gst/nsf/gstnsf.c:
** * gst/nsf/gstnsf.h:
** * gst/nsf/log.c:
** * gst/nsf/log.h:
** * gst/nsf/memguard.c:
** * gst/nsf/memguard.h:
** * gst/nsf/mmc5_snd.c:
** * gst/nsf/mmc5_snd.h:
** * gst/nsf/nes6502.c:
** * gst/nsf/nes6502.h:
** * gst/nsf/nes_apu.c:
** * gst/nsf/nes_apu.h:
** * gst/nsf/nsf.c:
** * gst/nsf/nsf.h:
** * gst/nsf/osd.h:
** * gst/nsf/types.h:
** * gst/nsf/vrc7_snd.c:
** * gst/nsf/vrc7_snd.h:
** * gst/nsf/vrcvisnd.c:
** * gst/nsf/vrcvisnd.h:
** Added NSF decoder plugin. Fixes 151192.
**
** Revision 1.6 2000/07/04 04:50:07 matt
** minor change to includes
**
** Revision 1.5 2000/07/03 02:18:16 matt
** added a few notes about potential failure cases
**
** Revision 1.4 2000/06/09 15:12:25 matt
** initial revision
**
*/
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