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A5200DS/arm9/source/emu/cpu.c

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/*
* cpu.c - 6502 CPU emulation
*
* Copyright (C) 1995-1998 David Firth
* Copyright (C) 1998-2005 Atari800 development team (see DOC/CREDITS)
*
* This file is part of the Atari800 emulator project which emulates
* the Atari 400, 800, 800XL, 130XE, and 5200 8-bit computers.
*
* Atari800 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.
*
* Atari800 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 Atari800; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
Configuration symbols
=====================
Define CPU65C02 if you don't want 6502 JMP() bug emulation.
Define NO_V_FLAG_VARIABLE to don't use local (static) variable V for the V flag.
Limitations & Known bugs
========================
There is no emulation of the bug in the BRK instruction executed simultaneously
with another interrupt.
The 6502 emulation ignores memory attributes for instruction fetch.
This is because the instruction must come from either RAM or ROM.
A program that executes instructions from within hardware addresses will fail
since there is never any usable code there.
The 6502 emulation also ignores memory attributes for accesses to page 0 and page 1.
*/
#include "nds.h"
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include "cpu.h"
#include "antic.h"
#include "atari.h"
#include "memory.h"
/* Windows headers define it */
#undef ABSOLUTE
//#define NO_V_FLAG_VARIABLE // Very slight speedup... we will check the processor status directly in the rare case of needing this...
#define CPU65C02 // Do not emulate the original 6502 bug on JMP
/* 6502 stack handling */
#define PL zGetByte(0x0100 + ++S)
#define PH(x) dPutByte(0x0100 + S--, x)
#define PHW(x) PH((x) >> 8); PH((x) & 0xff)
/* 6502 code fetching */
#define GET_PC() PC
#define SET_PC(newpc) (PC = (newpc))
#define PHPC PHW(PC)
#define GET_CODE_BYTE() dGetByte(PC++)
#define PEEK_CODE_BYTE() dGetByte(PC)
#define PEEK_CODE_WORD() dGetWord(PC)
/* Don't emulate the first write */
#define RMW_GetByte(x, addr) x = GetByte(addr);
/* 6502 registers. */
ULONG regPC __attribute__((section(".dtcm"))); // UNLONG here buys us a little speed as compiler doesn't have to mask it
UBYTE regA __attribute__((section(".dtcm")));
UBYTE regX __attribute__((section(".dtcm")));
UBYTE regY __attribute__((section(".dtcm")));
UBYTE regP __attribute__((section(".dtcm"))); // Processor Status Byte (Partial)
UBYTE regS __attribute__((section(".dtcm")));
UBYTE IRQ __attribute__((section(".dtcm")));
/* Transfer 6502 registers between global variables and local variables inside GO() */
//#define UPDATE_GLOBAL_REGS regPC = GET_PC(); regS = S; regA = A; regX = X; regY = Y
//#define UPDATE_LOCAL_REGS SET_PC(regPC); S = regS; A = regA; X = regX; Y = regY
#define UPDATE_GLOBAL_REGS regS = S;
#define UPDATE_LOCAL_REGS S = regS;
// Since we have our global CPU registers in fast memory, no need to transfer them in/out
#define PC regPC
#define A regA
#define Y regY
#define X regX
/* 6502 flags local to this module */
static UBYTE N __attribute__((section(".dtcm"))); /* bit7 set => N flag set */
#ifndef NO_V_FLAG_VARIABLE
static UBYTE V __attribute__((section(".dtcm"))); /* non-zero => V flag set */
#endif
static UBYTE Z __attribute__((section(".dtcm"))); /* zero => Z flag set */
static UBYTE C __attribute__((section(".dtcm"))); /* must be 0 or 1 */
/* B, D, I are always in regP */
inline void CPU_GetStatus(void)
{
#ifndef NO_V_FLAG_VARIABLE
regP = (N & 0x80) + (V ? 0x40 : 0) + (regP & 0x3c) + ((Z == 0) ? 0x02 : 0) + C;
#else
regP = (N & 0x80) + (regP & 0x7c) + ((Z == 0) ? 0x02 : 0) + C;
#endif
}
inline void CPU_PutStatus(void)
{
N = regP;
#ifndef NO_V_FLAG_VARIABLE
V = (regP & 0x40);
#endif
Z = (regP & 0x02) ^ 0x02;
C = (regP & 0x01);
}
/* Addressing modes */
inline UWORD zGetWord(UWORD x)
{
UWORD data = zGetByte(x);
data |= zGetByte(x+1) << 8;
return data;
}
#define OP_BYTE PEEK_CODE_BYTE()
#define OP_WORD PEEK_CODE_WORD()
#define IMMEDIATE GET_CODE_BYTE()
#define ABSOLUTE addr = PEEK_CODE_WORD(); PC += 2
#define ZPAGE addr = GET_CODE_BYTE()
#define ABSOLUTE_X addr = PEEK_CODE_WORD() + X; PC += 2
#define ABSOLUTE_Y addr = PEEK_CODE_WORD() + Y; PC += 2
#define INDIRECT_X addr = (UBYTE) (GET_CODE_BYTE() + X); addr = zGetWord(addr)
#define INDIRECT_Y addr = GET_CODE_BYTE(); addr = zGetWord(addr) + Y
#define ZPAGE_X addr = (UBYTE) (GET_CODE_BYTE() + X)
#define ZPAGE_Y addr = (UBYTE) (GET_CODE_BYTE() + Y)
/* Instructions */
#define AND(t_data) Z = N = A &= t_data
#define CMP(t_data) data = t_data; Z = N = A - data; C = (A >= data)
#define CPX(t_data) data = t_data; Z = N = X - data; C = (X >= data)
#define CPY(t_data) data = t_data; Z = N = Y - data; C = (Y >= data)
#define EOR(t_data) Z = N = A ^= t_data
#define LDA(t_data) Z = N = A = t_data
#define LDX(t_data) Z = N = X = t_data
#define LDY(t_data) Z = N = Y = t_data
#define ORA(t_data) Z = N = A |= t_data
#ifndef NO_V_FLAG_VARIABLE
#define PHP(x) data = (N & 0x80) + (V ? 0x40 : 0) + (regP & (x)) + ((Z == 0) ? 0x02 : 0) + C; PH(data)
#define PHPB0 PHP(0x2c) /* push flags with B flag clear (NMI, IRQ) */
#define PHPB1 PHP(0x3c) /* push flags with B flag set (PHP, BRK) */
#define PLP data = PL; N = data; V = (data & 0x40); Z = (data & 0x02) ^ 0x02; C = (data & 0x01); regP = (data & 0x0c) + 0x30
#else /* NO_V_FLAG_VARIABLE */
#define PHP(x) data = (N & 0x80) + (regP & (x)) + ((Z == 0) ? 0x02 : 0) + C; PH(data)
#define PHPB0 PHP(0x6c) /* push flags with B flag clear (NMI, IRQ) */
#define PHPB1 PHP(0x7c) /* push flags with B flag set (PHP, BRK) */
#define PLP data = PL; N = data; Z = (data & 0x02) ^ 0x02; C = (data & 0x01); regP = (data & 0x4c) + 0x30
#endif /* NO_V_FLAG_VARIABLE */
/* 1 or 2 extra cycles for conditional jumps -- We factored in the assumption that the branch would be taken (80+% of the time it is) so an extra cycle was already counted - we compensate with xpos-- below */
#define BRANCH(cond) \
if (cond) { \
int addr = (int) (SBYTE) IMMEDIATE; \
addr += GET_PC(); \
if ((addr ^ GET_PC()) & 0xff00) xpos++; \
SET_PC(addr); \
DONE \
} \
xpos--; \
PC++; \
DONE
/* 1 extra cycle for X (or Y) index overflow */
#define NCYCLES_X if ((UBYTE) addr < X) xpos++
#define NCYCLES_Y if ((UBYTE) addr < Y) xpos++
/* Triggers a Non-Maskable Interrupt */
void NMI(void)
{
UBYTE S = regS;
UBYTE data;
PHW(regPC);
PHPB0;
SetI;
regPC = dGetWordAligned(0xfffa);
regS = S;
xpos += 7; /* handling an interrupt by 6502 takes 7 cycles */
}
/* Check pending IRQ, helps in (not only) Lucasfilm games */
#define CPUCHECKIRQ \
if (IRQ && !(regP & I_FLAG) && xpos < xpos_limit) { \
PHPC; \
PHPB0; \
SetI; \
SET_PC(dGetWordAligned(0xfffe)); \
xpos += 7; \
}
/* 0 1 2 3 4 5 6 7 8 9 A B C D E F */
static UBYTE cycles[256] __attribute__((section(".dtcm"))) =
{
7, 6, 2, 8, 3, 3, 5, 5, 3, 2, 2, 2, 4, 4, 6, 6, /* 0x */
3, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7, /* 1x */
6, 6, 2, 8, 3, 3, 5, 5, 4, 2, 2, 2, 4, 4, 6, 6, /* 2x */
3, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7, /* 3x */
6, 6, 2, 8, 3, 3, 5, 5, 3, 2, 2, 2, 3, 4, 6, 6, /* 4x */
3, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7, /* 5x */
6, 6, 2, 8, 3, 3, 5, 5, 4, 2, 2, 2, 5, 4, 6, 6, /* 6x */
3, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7, /* 7x */
2, 6, 2, 6, 3, 3, 3, 3, 2, 2, 2, 2, 4, 4, 4, 4, /* 8x */
3, 6, 2, 6, 4, 4, 4, 4, 2, 5, 2, 5, 5, 5, 5, 5, /* 9x */
2, 6, 2, 6, 3, 3, 3, 3, 2, 2, 2, 2, 4, 4, 4, 4, /* Ax */
3, 5, 2, 5, 4, 4, 4, 4, 2, 4, 2, 4, 4, 4, 4, 4, /* Bx */
2, 6, 2, 8, 3, 3, 5, 5, 2, 2, 2, 2, 4, 4, 6, 6, /* Cx */
3, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7, /* Dx */
2, 6, 2, 8, 3, 3, 5, 5, 2, 2, 2, 2, 4, 4, 6, 6, /* Ex */
3, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7 /* Fx */
};
void GO_Banked(int limit)
{
#define OPCODE_ALIAS(code) opcode_##code:
#define DONE goto next;
static const void *opcode[256] __attribute__((section(".dtcm"))) =
{
&&opcode_00, &&opcode_01, &&opcode_02, &&opcode_03,
&&opcode_04, &&opcode_05, &&opcode_06, &&opcode_07,
&&opcode_08, &&opcode_09, &&opcode_0a, &&opcode_0b,
&&opcode_0c, &&opcode_0d, &&opcode_0e, &&opcode_0f,
&&opcode_10, &&opcode_11, &&opcode_12, &&opcode_13,
&&opcode_14, &&opcode_15, &&opcode_16, &&opcode_17,
&&opcode_18, &&opcode_19, &&opcode_1a, &&opcode_1b,
&&opcode_1c, &&opcode_1d, &&opcode_1e, &&opcode_1f,
&&opcode_20, &&opcode_21, &&opcode_22, &&opcode_23,
&&opcode_24, &&opcode_25, &&opcode_26, &&opcode_27,
&&opcode_28, &&opcode_29, &&opcode_2a, &&opcode_2b,
&&opcode_2c, &&opcode_2d, &&opcode_2e, &&opcode_2f,
&&opcode_30, &&opcode_31, &&opcode_32, &&opcode_33,
&&opcode_34, &&opcode_35, &&opcode_36, &&opcode_37,
&&opcode_38, &&opcode_39, &&opcode_3a, &&opcode_3b,
&&opcode_3c, &&opcode_3d, &&opcode_3e, &&opcode_3f,
&&opcode_40, &&opcode_41, &&opcode_42, &&opcode_43,
&&opcode_44, &&opcode_45, &&opcode_46, &&opcode_47,
&&opcode_48, &&opcode_49, &&opcode_4a, &&opcode_4b,
&&opcode_4c, &&opcode_4d, &&opcode_4e, &&opcode_4f,
&&opcode_50, &&opcode_51, &&opcode_52, &&opcode_53,
&&opcode_54, &&opcode_55, &&opcode_56, &&opcode_57,
&&opcode_58, &&opcode_59, &&opcode_5a, &&opcode_5b,
&&opcode_5c, &&opcode_5d, &&opcode_5e, &&opcode_5f,
&&opcode_60, &&opcode_61, &&opcode_62, &&opcode_63,
&&opcode_64, &&opcode_65, &&opcode_66, &&opcode_67,
&&opcode_68, &&opcode_69, &&opcode_6a, &&opcode_6b,
&&opcode_6c, &&opcode_6d, &&opcode_6e, &&opcode_6f,
&&opcode_70, &&opcode_71, &&opcode_72, &&opcode_73,
&&opcode_74, &&opcode_75, &&opcode_76, &&opcode_77,
&&opcode_78, &&opcode_79, &&opcode_7a, &&opcode_7b,
&&opcode_7c, &&opcode_7d, &&opcode_7e, &&opcode_7f,
&&opcode_80, &&opcode_81, &&opcode_82, &&opcode_83,
&&opcode_84, &&opcode_85, &&opcode_86, &&opcode_87,
&&opcode_88, &&opcode_89, &&opcode_8a, &&opcode_8b,
&&opcode_8c, &&opcode_8d, &&opcode_8e, &&opcode_8f,
&&opcode_90, &&opcode_91, &&opcode_92, &&opcode_93,
&&opcode_94, &&opcode_95, &&opcode_96, &&opcode_97,
&&opcode_98, &&opcode_99, &&opcode_9a, &&opcode_9b,
&&opcode_9c, &&opcode_9d, &&opcode_9e, &&opcode_9f,
&&opcode_a0, &&opcode_a1, &&opcode_a2, &&opcode_a3,
&&opcode_a4, &&opcode_a5, &&opcode_a6, &&opcode_a7,
&&opcode_a8, &&opcode_a9, &&opcode_aa, &&opcode_ab,
&&opcode_ac, &&opcode_ad, &&opcode_ae, &&opcode_af,
&&opcode_b0, &&opcode_b1, &&opcode_b2, &&opcode_b3,
&&opcode_b4, &&opcode_b5, &&opcode_b6, &&opcode_b7,
&&opcode_b8, &&opcode_b9, &&opcode_ba, &&opcode_bb,
&&opcode_bc, &&opcode_bd, &&opcode_be, &&opcode_bf,
&&opcode_c0, &&opcode_c1, &&opcode_c2, &&opcode_c3,
&&opcode_c4, &&opcode_c5, &&opcode_c6, &&opcode_c7,
&&opcode_c8, &&opcode_c9, &&opcode_ca, &&opcode_cb,
&&opcode_cc, &&opcode_cd, &&opcode_ce, &&opcode_cf,
&&opcode_d0, &&opcode_d1, &&opcode_d2, &&opcode_d3,
&&opcode_d4, &&opcode_d5, &&opcode_d6, &&opcode_d7,
&&opcode_d8, &&opcode_d9, &&opcode_da, &&opcode_db,
&&opcode_dc, &&opcode_dd, &&opcode_de, &&opcode_df,
&&opcode_e0, &&opcode_e1, &&opcode_e2, &&opcode_e3,
&&opcode_e4, &&opcode_e5, &&opcode_e6, &&opcode_e7,
&&opcode_e8, &&opcode_e9, &&opcode_ea, &&opcode_eb,
&&opcode_ec, &&opcode_ed, &&opcode_ee, &&opcode_ef,
&&opcode_f0, &&opcode_f1, &&opcode_f2, &&opcode_f3,
&&opcode_f4, &&opcode_f5, &&opcode_f6, &&opcode_f7,
&&opcode_f8, &&opcode_f9, &&opcode_fa, &&opcode_fb,
&&opcode_fc, &&opcode_fd, &&opcode_fe, &&opcode_ff,
};
#define OPCODE(code) OPCODE_ALIAS(code)
UWORD addr;
UBYTE data;
UBYTE S;
#define insn data
/*
This used to be in the main loop but has been removed to improve
execution speed. It does not seem to have any adverse effect on
the emulation for two reasons:
1. NMI's will can only be raised in antic.c - there is
no way an NMI can be generated whilst in this routine.
2. The timing of the IRQs are not that critical. */
if (wsync_halt) {
if (limit < WSYNC_C)
return;
xpos = WSYNC_C;
wsync_halt = 0;
}
xpos_limit = limit; /* needed for WSYNC store inside ANTIC */
UPDATE_LOCAL_REGS;
CPUCHECKIRQ;
// A jump to the next instruction will land us here just before the test on xpos
next:
while (xpos < xpos_limit)
{
insn = GET_CODE_BYTE();
xpos += cycles[insn];
goto *opcode[insn];
OPCODE(00) /* BRK */
PC++;
PHPC;
PHPB1;
SetI;
SET_PC(dGetWordAligned(0xfffe));
DONE
OPCODE(01) /* ORA (ab,x) */
INDIRECT_X;
ORA(GetByte(addr));
DONE
OPCODE(03) /* ASO (ab,x) [unofficial - ASL then ORA with Acc] */
INDIRECT_X;
aso:
RMW_GetByte(data, addr);
C = (data & 0x80) ? 1 : 0;
data <<= 1;
PutByte(addr, data);
Z = N = A |= data;
DONE
OPCODE_ALIAS(04) /* NOP ab [unofficial - skip byte] */
OPCODE_ALIAS(44)
OPCODE(64)
PC++;
DONE
OPCODE_ALIAS(14) /* NOP ab,x [unofficial - skip byte] */
OPCODE_ALIAS(34)
OPCODE_ALIAS(54)
OPCODE_ALIAS(74)
OPCODE_ALIAS(d4)
OPCODE(f4)
PC++;
DONE
OPCODE_ALIAS(80) /* NOP #ab [unofficial - skip byte] */
OPCODE_ALIAS(82)
OPCODE_ALIAS(89)
OPCODE_ALIAS(c2)
OPCODE(e2)
PC++;
DONE
OPCODE(05) /* ORA ab */
ZPAGE;
ORA(zGetByte(addr));
DONE
OPCODE(06) /* ASL ab */
ZPAGE;
data = zGetByte(addr);
C = (data & 0x80) ? 1 : 0;
Z = N = data << 1;
dPutByte(addr, Z);
DONE
OPCODE(07) /* ASO ab [unofficial - ASL then ORA with Acc] */
ZPAGE;
aso_zpage:
data = zGetByte(addr);
C = (data & 0x80) ? 1 : 0;
data <<= 1;
dPutByte(addr, data);
Z = N = A |= data;
DONE
OPCODE(08) /* PHP */
PHPB1;
DONE
OPCODE(09) /* ORA #ab */
ORA(IMMEDIATE);
DONE
OPCODE(0a) /* ASL */
C = (A & 0x80) ? 1 : 0;
Z = N = A <<= 1;
DONE
OPCODE_ALIAS(0b) /* ANC #ab [unofficial - AND then copy N to C (Fox) */
OPCODE(2b)
AND(IMMEDIATE);
C = N >= 0x80;
DONE
OPCODE(0c) /* NOP abcd [unofficial - skip word] */
PC += 2;
DONE
OPCODE(0d) /* ORA abcd */
ABSOLUTE;
ORA(GetByte(addr));
DONE
OPCODE(0e) /* ASL abcd */
ABSOLUTE;
RMW_GetByte(data, addr);
C = (data & 0x80) ? 1 : 0;
Z = N = data << 1;
PutByte(addr, Z);
DONE
OPCODE(0f) /* ASO abcd [unofficial - ASL then ORA with Acc] */
ABSOLUTE;
goto aso;
OPCODE(10) /* BPL */
BRANCH(!(N & 0x80))
OPCODE(11) /* ORA (ab),y */
INDIRECT_Y;
NCYCLES_Y;
ORA(GetByte(addr));
DONE
OPCODE(13) /* ASO (ab),y [unofficial - ASL then ORA with Acc] */
INDIRECT_Y;
goto aso;
OPCODE(15) /* ORA ab,x */
ZPAGE_X;
ORA(zGetByte(addr));
DONE
OPCODE(16) /* ASL ab,x */
ZPAGE_X;
data = zGetByte(addr);
C = (data & 0x80) ? 1 : 0;
Z = N = data << 1;
dPutByte(addr, Z);
DONE
OPCODE(17) /* ASO ab,x [unofficial - ASL then ORA with Acc] */
ZPAGE_X;
goto aso_zpage;
OPCODE(18) /* CLC */
C = 0;
DONE
OPCODE(19) /* ORA abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
ORA(GetByte(addr));
DONE
OPCODE(1b) /* ASO abcd,y [unofficial - ASL then ORA with Acc] */
ABSOLUTE_Y;
goto aso;
OPCODE_ALIAS(1c) /* NOP abcd,x [unofficial - skip word] */
OPCODE_ALIAS(3c)
OPCODE_ALIAS(5c)
OPCODE_ALIAS(7c)
OPCODE_ALIAS(dc)
OPCODE(fc)
if (OP_BYTE + X >= 0x100)
xpos++;
PC += 2;
DONE
OPCODE(1d) /* ORA abcd,x */
ABSOLUTE_X;
NCYCLES_X;
ORA(GetByte(addr));
DONE
OPCODE(1e) /* ASL abcd,x */
ABSOLUTE_X;
RMW_GetByte(data, addr);
C = (data & 0x80) ? 1 : 0;
Z = N = data << 1;
PutByte(addr, Z);
DONE
OPCODE(1f) /* ASO abcd,x [unofficial - ASL then ORA with Acc] */
ABSOLUTE_X;
goto aso;
OPCODE(20) /* JSR abcd */
{
UWORD retaddr = GET_PC() + 1;
PHW(retaddr);
}
SET_PC(OP_WORD);
DONE
OPCODE(21) /* AND (ab,x) */
INDIRECT_X;
AND(GetByte(addr));
DONE
OPCODE(23) /* RLA (ab,x) [unofficial - ROL Mem, then AND with A] */
INDIRECT_X;
rla:
RMW_GetByte(data, addr);
if (C) {
C = (data & 0x80) ? 1 : 0;
data = (data << 1) + 1;
}
else {
C = (data & 0x80) ? 1 : 0;
data = (data << 1);
}
PutByte(addr, data);
Z = N = A &= data;
DONE
OPCODE(24) /* BIT ab */
ZPAGE;
N = zGetByte(addr);
#ifndef NO_V_FLAG_VARIABLE
V = N & 0x40;
#else
regP = (regP & 0xbf) + (N & 0x40);
#endif
Z = (A & N);
DONE
OPCODE(25) /* AND ab */
ZPAGE;
AND(zGetByte(addr));
DONE
OPCODE(26) /* ROL ab */
ZPAGE;
data = zGetByte(addr);
Z = N = (data << 1) + C;
C = (data & 0x80) ? 1 : 0;
dPutByte(addr, Z);
DONE
OPCODE(27) /* RLA ab [unofficial - ROL Mem, then AND with A] */
ZPAGE;
rla_zpage:
data = zGetByte(addr);
if (C) {
C = (data & 0x80) ? 1 : 0;
data = (data << 1) + 1;
}
else {
C = (data & 0x80) ? 1 : 0;
data = (data << 1);
}
dPutByte(addr, data);
Z = N = A &= data;
DONE
OPCODE(28) /* PLP */
PLP;
CPUCHECKIRQ;
DONE
OPCODE(29) /* AND #ab */
AND(IMMEDIATE);
DONE
OPCODE(2a) /* ROL */
Z = N = (A << 1) + C;
C = (A & 0x80) ? 1 : 0;
A = Z;
DONE
OPCODE(2c) /* BIT abcd */
ABSOLUTE;
N = GetByte(addr);
#ifndef NO_V_FLAG_VARIABLE
V = N & 0x40;
#else
regP = (regP & 0xbf) + (N & 0x40);
#endif
Z = (A & N);
DONE
OPCODE(2d) /* AND abcd */
ABSOLUTE;
AND(GetByte(addr));
DONE
OPCODE(2e) /* ROL abcd */
ABSOLUTE;
RMW_GetByte(data, addr);
Z = N = (data << 1) + C;
C = (data & 0x80) ? 1 : 0;
PutByte(addr, Z);
DONE
OPCODE(2f) /* RLA abcd [unofficial - ROL Mem, then AND with A] */
ABSOLUTE;
goto rla;
OPCODE(30) /* BMI */
BRANCH(N & 0x80)
OPCODE(31) /* AND (ab),y */
INDIRECT_Y;
NCYCLES_Y;
AND(GetByte(addr));
DONE
OPCODE(33) /* RLA (ab),y [unofficial - ROL Mem, then AND with A] */
INDIRECT_Y;
goto rla;
OPCODE(35) /* AND ab,x */
ZPAGE_X;
AND(zGetByte(addr));
DONE
OPCODE(36) /* ROL ab,x */
ZPAGE_X;
data = zGetByte(addr);
Z = N = (data << 1) + C;
C = (data & 0x80) ? 1 : 0;
dPutByte(addr, Z);
DONE
OPCODE(37) /* RLA ab,x [unofficial - ROL Mem, then AND with A] */
ZPAGE_X;
goto rla_zpage;
OPCODE(38) /* SEC */
C = 1;
DONE
OPCODE(39) /* AND abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
AND(GetByte(addr));
DONE
OPCODE(3b) /* RLA abcd,y [unofficial - ROL Mem, then AND with A] */
ABSOLUTE_Y;
goto rla;
OPCODE(3d) /* AND abcd,x */
ABSOLUTE_X;
NCYCLES_X;
AND(GetByte(addr));
DONE
OPCODE(3e) /* ROL abcd,x */
ABSOLUTE_X;
RMW_GetByte(data, addr);
Z = N = (data << 1) + C;
C = (data & 0x80) ? 1 : 0;
PutByte(addr, Z);
DONE
OPCODE(3f) /* RLA abcd,x [unofficial - ROL Mem, then AND with A] */
ABSOLUTE_X;
goto rla;
OPCODE(40) /* RTI */
PLP;
data = PL;
SET_PC((PL << 8) + data);
CPUCHECKIRQ;
DONE
OPCODE(41) /* EOR (ab,x) */
INDIRECT_X;
EOR(GetByte(addr));
DONE
OPCODE(43) /* LSE (ab,x) [unofficial - LSR then EOR result with A] */
INDIRECT_X;
lse:
RMW_GetByte(data, addr);
C = data & 1;
data >>= 1;
PutByte(addr, data);
Z = N = A ^= data;
DONE
OPCODE(45) /* EOR ab */
ZPAGE;
EOR(zGetByte(addr));
DONE
OPCODE(46) /* LSR ab */
ZPAGE;
data = zGetByte(addr);
C = data & 1;
Z = data >> 1;
N = 0;
dPutByte(addr, Z);
DONE
OPCODE(47) /* LSE ab [unofficial - LSR then EOR result with A] */
ZPAGE;
lse_zpage:
data = zGetByte(addr);
C = data & 1;
data >>= 1;
dPutByte(addr, data);
Z = N = A ^= data;
DONE
OPCODE(48) /* PHA */
PH(A);
DONE
OPCODE(49) /* EOR #ab */
EOR(IMMEDIATE);
DONE
OPCODE(4a) /* LSR */
C = A & 1;
Z = N = A >>= 1;
DONE
OPCODE(4b) /* ALR #ab [unofficial - Acc AND Data, LSR result] */
data = A & IMMEDIATE;
C = data & 1;
Z = N = A = (data >> 1);
DONE
OPCODE(4c) /* JMP abcd */
SET_PC(OP_WORD);
DONE
OPCODE(4d) /* EOR abcd */
ABSOLUTE;
EOR(GetByte(addr));
DONE
OPCODE(4e) /* LSR abcd */
ABSOLUTE;
RMW_GetByte(data, addr);
C = data & 1;
Z = data >> 1;
N = 0;
PutByte(addr, Z);
DONE
OPCODE(4f) /* LSE abcd [unofficial - LSR then EOR result with A] */
ABSOLUTE;
goto lse;
OPCODE(50) /* BVC */
#ifndef NO_V_FLAG_VARIABLE
BRANCH(!V)
#else
BRANCH(!(regP & 0x40))
#endif
OPCODE(51) /* EOR (ab),y */
INDIRECT_Y;
NCYCLES_Y;
EOR(GetByte(addr));
DONE
OPCODE(53) /* LSE (ab),y [unofficial - LSR then EOR result with A] */
INDIRECT_Y;
goto lse;
OPCODE(55) /* EOR ab,x */
ZPAGE_X;
EOR(zGetByte(addr));
DONE
OPCODE(56) /* LSR ab,x */
ZPAGE_X;
data = zGetByte(addr);
C = data & 1;
Z = data >> 1;
N = 0;
dPutByte(addr, Z);
DONE
OPCODE(57) /* LSE ab,x [unofficial - LSR then EOR result with A] */
ZPAGE_X;
goto lse_zpage;
OPCODE(58) /* CLI */
ClrI;
CPUCHECKIRQ;
DONE
OPCODE(59) /* EOR abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
EOR(GetByte(addr));
DONE
OPCODE(5b) /* LSE abcd,y [unofficial - LSR then EOR result with A] */
ABSOLUTE_Y;
goto lse;
OPCODE(5d) /* EOR abcd,x */
ABSOLUTE_X;
NCYCLES_X;
EOR(GetByte(addr));
DONE
OPCODE(5e) /* LSR abcd,x */
ABSOLUTE_X;
RMW_GetByte(data, addr);
C = data & 1;
Z = data >> 1;
N = 0;
PutByte(addr, Z);
DONE
OPCODE(5f) /* LSE abcd,x [unofficial - LSR then EOR result with A] */
ABSOLUTE_X;
goto lse;
OPCODE(60) /* RTS */
data = PL;
SET_PC((PL << 8) + data + 1);
DONE
OPCODE(61) /* ADC (ab,x) */
INDIRECT_X;
data = GetByte(addr);
goto adc;
OPCODE(63) /* RRA (ab,x) [unofficial - ROR Mem, then ADC to Acc] */
INDIRECT_X;
rra:
RMW_GetByte(data, addr);
if (C) {
C = data & 1;
data = (data >> 1) + 0x80;
}
else {
C = data & 1;
data >>= 1;
}
PutByte(addr, data);
goto adc;
OPCODE(65) /* ADC ab */
ZPAGE;
data = zGetByte(addr);
goto adc;
OPCODE(66) /* ROR ab */
ZPAGE;
data = zGetByte(addr);
Z = N = (C << 7) + (data >> 1);
C = data & 1;
dPutByte(addr, Z);
DONE
OPCODE(67) /* RRA ab [unofficial - ROR Mem, then ADC to Acc] */
ZPAGE;
rra_zpage:
data = zGetByte(addr);
if (C) {
C = data & 1;
data = (data >> 1) + 0x80;
}
else {
C = data & 1;
data >>= 1;
}
dPutByte(addr, data);
goto adc;
OPCODE(68) /* PLA */
Z = N = A = PL;
DONE
OPCODE(69) /* ADC #ab */
data = IMMEDIATE;
goto adc;
OPCODE(6a) /* ROR */
Z = N = (C << 7) + (A >> 1);
C = A & 1;
A = Z;
DONE
OPCODE(6b) /* ARR #ab [unofficial - Acc AND Data, ROR result] */
/* It does some 'BCD fixup' if D flag is set */
/* MPC 05/24/00 */
data = A & IMMEDIATE;
if (regP & D_FLAG) {
UBYTE temp = (data >> 1) + (C << 7);
Z = N = temp;
#ifndef NO_V_FLAG_VARIABLE
V = ((temp ^ data) & 0x40);
#else
regP = (regP & 0xbf) + ((temp ^ data) & 0x40);
#endif
if ((data & 0x0F) + (data & 0x01) > 5)
temp = (temp & 0xF0) + ((temp + 0x6) & 0x0F);
if (data + (data & 0x10) >= 0x60) {
temp += 0x60;
C = 1;
}
else
C = 0;
A = (UBYTE) temp;
}
else {
Z = N = A = (data >> 1) + (C << 7);
C = data >> 7;
#ifndef NO_V_FLAG_VARIABLE
V = C ^ ((A >> 5) & 1);
#else
regP = (regP & 0xbf) + ((A ^ data) & 0x40);
#endif
}
DONE
OPCODE(6c) /* JMP (abcd) */
ABSOLUTE;
#ifdef CPU65C02
/* XXX: if ((UBYTE) addr == 0xff) xpos++; */
SET_PC(dGetWord(addr));
#else
/* original 6502 had a bug in JMP (addr) when addr crossed page boundary */
if ((UBYTE) addr == 0xff)
SET_PC((dGetByte(addr - 0xff) << 8) + dGetByte(addr));
else
SET_PC(dGetWord(addr));
#endif
DONE
OPCODE(6d) /* ADC abcd */
ABSOLUTE;
data = GetByte(addr);
goto adc;
OPCODE(6e) /* ROR abcd */
ABSOLUTE;
RMW_GetByte(data, addr);
Z = N = (C << 7) + (data >> 1);
C = data & 1;
PutByte(addr, Z);
DONE
OPCODE(6f) /* RRA abcd [unofficial - ROR Mem, then ADC to Acc] */
ABSOLUTE;
goto rra;
OPCODE(70) /* BVS */
#ifndef NO_V_FLAG_VARIABLE
BRANCH(V)
#else
BRANCH(regP & 0x40)
#endif
OPCODE(71) /* ADC (ab),y */
INDIRECT_Y;
NCYCLES_Y;
data = GetByte(addr);
goto adc;
OPCODE(73) /* RRA (ab),y [unofficial - ROR Mem, then ADC to Acc] */
INDIRECT_Y;
goto rra;
OPCODE(75) /* ADC ab,x */
ZPAGE_X;
data = zGetByte(addr);
goto adc;
OPCODE(76) /* ROR ab,x */
ZPAGE_X;
data = zGetByte(addr);
Z = N = (C << 7) + (data >> 1);
C = data & 1;
dPutByte(addr, Z);
DONE
OPCODE(77) /* RRA ab,x [unofficial - ROR Mem, then ADC to Acc] */
ZPAGE_X;
goto rra_zpage;
OPCODE(78) /* SEI */
SetI;
DONE
OPCODE(79) /* ADC abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
data = GetByte(addr);
goto adc;
OPCODE(7b) /* RRA abcd,y [unofficial - ROR Mem, then ADC to Acc] */
ABSOLUTE_Y;
goto rra;
OPCODE(7d) /* ADC abcd,x */
ABSOLUTE_X;
NCYCLES_X;
data = GetByte(addr);
goto adc;
OPCODE(7e) /* ROR abcd,x */
ABSOLUTE_X;
RMW_GetByte(data, addr);
Z = N = (C << 7) + (data >> 1);
C = data & 1;
PutByte(addr, Z);
DONE
OPCODE(7f) /* RRA abcd,x [unofficial - ROR Mem, then ADC to Acc] */
ABSOLUTE_X;
goto rra;
OPCODE(81) /* STA (ab,x) */
INDIRECT_X;
PutByte(addr, A);
DONE
/* AXS doesn't change flags and SAX is better name for it (Fox) */
OPCODE(83) /* SAX (ab,x) [unofficial - Store result A AND X */
INDIRECT_X;
data = A & X;
PutByte(addr, data);
DONE
OPCODE(84) /* STY ab */
ZPAGE;
dPutByte(addr, Y);
DONE
OPCODE(85) /* STA ab */
ZPAGE;
dPutByte(addr, A);
DONE
OPCODE(86) /* STX ab */
ZPAGE;
dPutByte(addr, X);
DONE
OPCODE(87) /* SAX ab [unofficial - Store result A AND X] */
ZPAGE;
data = A & X;
dPutByte(addr, data);
DONE
OPCODE(88) /* DEY */
Z = N = --Y;
DONE
OPCODE(8a) /* TXA */
Z = N = A = X;
DONE
OPCODE(8b) /* ANE #ab [unofficial - A AND X AND (Mem OR $EF) to Acc] (Fox) */
data = IMMEDIATE;
N = Z = A & X & data;
A &= X & (data | 0xef);
DONE
OPCODE(8c) /* STY abcd */
ABSOLUTE;
PutByte(addr, Y);
DONE
OPCODE(8d) /* STA abcd */
ABSOLUTE;
PutByte(addr, A);
DONE
OPCODE(8e) /* STX abcd */
ABSOLUTE;
PutByte(addr, X);
DONE
OPCODE(8f) /* SAX abcd [unofficial - Store result A AND X] */
ABSOLUTE;
data = A & X;
PutByte(addr, data);
DONE
OPCODE(90) /* BCC */
BRANCH(!C)
OPCODE(91) /* STA (ab),y */
INDIRECT_Y;
PutByte(addr, A);
DONE
OPCODE(93) /* SHA (ab),y [unofficial, UNSTABLE - Store A AND X AND (H+1) ?] (Fox) */
/* It seems previous memory value is important - also in 9f */
ZPAGE;
data = zGetByte((UBYTE) (addr + 1)); /* Get high byte from zpage */
data = A & X & (data + 1);
addr = zGetWord(addr) + Y;
PutByte(addr, data);
DONE
OPCODE(94) /* STY ab,x */
ZPAGE_X;
dPutByte(addr, Y);
DONE
OPCODE(95) /* STA ab,x */
ZPAGE_X;
dPutByte(addr, A);
DONE
OPCODE(96) /* STX ab,y */
ZPAGE_Y;
dPutByte(addr, X);
DONE
OPCODE(97) /* SAX ab,y [unofficial - Store result A AND X] */
ZPAGE_Y;
data = A & X;
dPutByte(addr, data);
DONE
OPCODE(98) /* TYA */
Z = N = A = Y;
DONE
OPCODE(99) /* STA abcd,y */
ABSOLUTE_Y;
PutByte(addr, A);
DONE
OPCODE(9a) /* TXS */
S = X;
DONE
OPCODE(9b) /* SHS abcd,y [unofficial, UNSTABLE] (Fox) */
/* Transfer A AND X to S, then store S AND (H+1)] */
/* S seems to be stable, only memory values vary */
ABSOLUTE;
S = A & X;
data = S & ((addr >> 8) + 1);
addr += Y;
PutByte(addr, data);
DONE
OPCODE(9c) /* SHY abcd,x [unofficial - Store Y and (H+1)] (Fox) */
/* Seems to be stable */
ABSOLUTE;
/* MPC 05/24/00 */
data = Y & ((UBYTE) ((addr >> 8) + 1));
addr += X;
PutByte(addr, data);
DONE
OPCODE(9d) /* STA abcd,x */
ABSOLUTE_X;
PutByte(addr, A);
DONE
OPCODE(9e) /* SHX abcd,y [unofficial - Store X and (H+1)] (Fox) */
/* Seems to be stable */
ABSOLUTE;
/* MPC 05/24/00 */
data = X & ((UBYTE) ((addr >> 8) + 1));
addr += Y;
PutByte(addr, data);
DONE
OPCODE(9f) /* SHA abcd,y [unofficial, UNSTABLE - Store A AND X AND (H+1) ?] (Fox) */
ABSOLUTE;
data = A & X & ((addr >> 8) + 1);
addr += Y;
PutByte(addr, data);
DONE
OPCODE(a0) /* LDY #ab */
LDY(IMMEDIATE);
DONE
OPCODE(a1) /* LDA (ab,x) */
INDIRECT_X;
LDA(GetByte(addr));
DONE
OPCODE(a2) /* LDX #ab */
LDX(IMMEDIATE);
DONE
OPCODE(a3) /* LAX (ab,x) [unofficial] */
INDIRECT_X;
Z = N = X = A = GetByte(addr);
DONE
OPCODE(a4) /* LDY ab */
ZPAGE;
LDY(zGetByte(addr));
DONE
OPCODE(a5) /* LDA ab */
ZPAGE;
LDA(zGetByte(addr));
DONE
OPCODE(a6) /* LDX ab */
ZPAGE;
LDX(zGetByte(addr));
DONE
OPCODE(a7) /* LAX ab [unofficial] */
ZPAGE;
Z = N = X = A = zGetByte(addr);
DONE
OPCODE(a8) /* TAY */
Z = N = Y = A;
DONE
OPCODE(a9) /* LDA #ab */
LDA(IMMEDIATE);
DONE
OPCODE(aa) /* TAX */
Z = N = X = A;
DONE
OPCODE(ab) /* ANX #ab [unofficial - AND #ab, then TAX] */
Z = N = X = A &= IMMEDIATE;
DONE
OPCODE(ac) /* LDY abcd */
ABSOLUTE;
LDY(GetByte(addr));
DONE
OPCODE(ad) /* LDA abcd */
ABSOLUTE;
LDA(GetByte(addr));
DONE
OPCODE(ae) /* LDX abcd */
ABSOLUTE;
LDX(GetByte(addr));
DONE
OPCODE(af) /* LAX abcd [unofficial] */
ABSOLUTE;
Z = N = X = A = GetByte(addr);
DONE
OPCODE(b0) /* BCS */
BRANCH(C)
OPCODE(b1) /* LDA (ab),y */
INDIRECT_Y;
NCYCLES_Y;
LDA(GetByte(addr));
DONE
OPCODE(b3) /* LAX (ab),y [unofficial] */
INDIRECT_Y;
NCYCLES_Y;
Z = N = X = A = GetByte(addr);
DONE
OPCODE(b4) /* LDY ab,x */
ZPAGE_X;
LDY(zGetByte(addr));
DONE
OPCODE(b5) /* LDA ab,x */
ZPAGE_X;
LDA(zGetByte(addr));
DONE
OPCODE(b6) /* LDX ab,y */
ZPAGE_Y;
LDX(zGetByte(addr));
DONE
OPCODE(b7) /* LAX ab,y [unofficial] */
ZPAGE_Y;
Z = N = X = A = zGetByte(addr);
DONE
OPCODE(b8) /* CLV */
#ifndef NO_V_FLAG_VARIABLE
V = 0;
#else
ClrV;
#endif
DONE
OPCODE(b9) /* LDA abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
LDA(GetByte(addr));
DONE
OPCODE(ba) /* TSX */
Z = N = X = S;
DONE
/* AXA [unofficial - original decode by R.Sterba and R.Petruzela 15.1.1998 :-)]
AXA - this is our new imaginative name for instruction with opcode hex BB.
AXA - Store Mem AND #$FD to Acc and X, then set stackpoint to value (Acc - 4)
It's cool! :-)
LAS - this is better name for this :) (Fox)
It simply ANDs stack pointer with Mem, then transfers result to A and X
*/
OPCODE(bb) /* LAS abcd,y [unofficial - AND S with Mem, transfer to A and X (Fox) */
ABSOLUTE_Y;
NCYCLES_Y;
Z = N = A = X = S &= GetByte(addr);
DONE
OPCODE(bc) /* LDY abcd,x */
ABSOLUTE_X;
NCYCLES_X;
LDY(GetByte(addr));
DONE
OPCODE(bd) /* LDA abcd,x */
ABSOLUTE_X;
NCYCLES_X;
LDA(GetByte(addr));
DONE
OPCODE(be) /* LDX abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
LDX(GetByte(addr));
DONE
OPCODE(bf) /* LAX abcd,y [unofficial] */
ABSOLUTE_Y;
NCYCLES_Y;
Z = N = X = A = GetByte(addr);
DONE
OPCODE(c0) /* CPY #ab */
CPY(IMMEDIATE);
DONE
OPCODE(c1) /* CMP (ab,x) */
INDIRECT_X;
CMP(GetByte(addr));
DONE
OPCODE(c3) /* DCM (ab,x) [unofficial - DEC Mem then CMP with Acc] */
INDIRECT_X;
dcm:
RMW_GetByte(data, addr);
data--;
PutByte(addr, data);
CMP(data);
DONE
OPCODE(c4) /* CPY ab */
ZPAGE;
CPY(zGetByte(addr));
DONE
OPCODE(c5) /* CMP ab */
ZPAGE;
CMP(zGetByte(addr));
DONE
OPCODE(c6) /* DEC ab */
ZPAGE;
Z = N = zGetByte(addr) - 1;
dPutByte(addr, Z);
DONE
OPCODE(c7) /* DCM ab [unofficial - DEC Mem then CMP with Acc] */
ZPAGE;
dcm_zpage:
data = zGetByte(addr) - 1;
dPutByte(addr, data);
CMP(data);
DONE
OPCODE(c8) /* INY */
Z = N = ++Y;
DONE
OPCODE(c9) /* CMP #ab */
CMP(IMMEDIATE);
DONE
OPCODE(ca) /* DEX */
Z = N = --X;
DONE
OPCODE(cb) /* SBX #ab [unofficial - store ((A AND X) - Mem) in X] (Fox) */
X &= A;
data = IMMEDIATE;
C = X >= data;
/* MPC 05/24/00 */
Z = N = X -= data;
DONE
OPCODE(cc) /* CPY abcd */
ABSOLUTE;
CPY(GetByte(addr));
DONE
OPCODE(cd) /* CMP abcd */
ABSOLUTE;
CMP(GetByte(addr));
DONE
OPCODE(ce) /* DEC abcd */
ABSOLUTE;
RMW_GetByte(Z, addr);
N = --Z;
PutByte(addr, Z);
DONE
OPCODE(cf) /* DCM abcd [unofficial - DEC Mem then CMP with Acc] */
ABSOLUTE;
goto dcm;
OPCODE(d0) /* BNE */
BRANCH(Z)
OPCODE(d1) /* CMP (ab),y */
INDIRECT_Y;
NCYCLES_Y;
CMP(GetByte(addr));
DONE
OPCODE(d3) /* DCM (ab),y [unofficial - DEC Mem then CMP with Acc] */
INDIRECT_Y;
goto dcm;
OPCODE(d5) /* CMP ab,x */
ZPAGE_X;
CMP(zGetByte(addr));
Z = N = A - data;
C = (A >= data);
DONE
OPCODE(d6) /* DEC ab,x */
ZPAGE_X;
Z = N = zGetByte(addr) - 1;
dPutByte(addr, Z);
DONE
OPCODE(d7) /* DCM ab,x [unofficial - DEC Mem then CMP with Acc] */
ZPAGE_X;
goto dcm_zpage;
OPCODE(d8) /* CLD */
ClrD;
DONE
OPCODE(d9) /* CMP abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
CMP(GetByte(addr));
DONE
OPCODE(db) /* DCM abcd,y [unofficial - DEC Mem then CMP with Acc] */
ABSOLUTE_Y;
goto dcm;
OPCODE(dd) /* CMP abcd,x */
ABSOLUTE_X;
NCYCLES_X;
CMP(GetByte(addr));
DONE
OPCODE(de) /* DEC abcd,x */
ABSOLUTE_X;
RMW_GetByte(Z, addr);
N = --Z;
PutByte(addr, Z);
DONE
OPCODE(df) /* DCM abcd,x [unofficial - DEC Mem then CMP with Acc] */
ABSOLUTE_X;
goto dcm;
OPCODE(e0) /* CPX #ab */
CPX(IMMEDIATE);
DONE
OPCODE(e1) /* SBC (ab,x) */
INDIRECT_X;
data = GetByte(addr);
goto sbc;
OPCODE(e3) /* INS (ab,x) [unofficial - INC Mem then SBC with Acc] */
INDIRECT_X;
ins:
RMW_GetByte(data, addr);
++data;
PutByte(addr, data);
goto sbc;
OPCODE(e4) /* CPX ab */
ZPAGE;
CPX(zGetByte(addr));
DONE
OPCODE(e5) /* SBC ab */
ZPAGE;
data = zGetByte(addr);
goto sbc;
OPCODE(e6) /* INC ab */
ZPAGE;
Z = N = zGetByte(addr) + 1;
dPutByte(addr, Z);
DONE
OPCODE(e7) /* INS ab [unofficial - INC Mem then SBC with Acc] */
ZPAGE;
ins_zpage:
data = zGetByte(addr) + 1;
dPutByte(addr, data);
goto sbc;
OPCODE(e8) /* INX */
Z = N = ++X;
DONE
OPCODE_ALIAS(e9) /* SBC #ab */
OPCODE(eb) /* SBC #ab [unofficial] */
data = IMMEDIATE;
goto sbc;
OPCODE_ALIAS(ea) /* NOP */
OPCODE_ALIAS(1a) /* NOP [unofficial] */
OPCODE_ALIAS(3a)
OPCODE_ALIAS(5a)
OPCODE_ALIAS(7a)
OPCODE_ALIAS(da)
OPCODE(fa)
DONE
OPCODE(ec) /* CPX abcd */
ABSOLUTE;
CPX(GetByte(addr));
DONE
OPCODE(ed) /* SBC abcd */
ABSOLUTE;
data = GetByte(addr);
goto sbc;
OPCODE(ee) /* INC abcd */
ABSOLUTE;
RMW_GetByte(Z, addr);
N = ++Z;
PutByte(addr, Z);
DONE
OPCODE(ef) /* INS abcd [unofficial - INC Mem then SBC with Acc] */
ABSOLUTE;
goto ins;
OPCODE(f0) /* BEQ */
BRANCH(!Z)
OPCODE(f1) /* SBC (ab),y */
INDIRECT_Y;
NCYCLES_Y;
data = GetByte(addr);
goto sbc;
OPCODE(f3) /* INS (ab),y [unofficial - INC Mem then SBC with Acc] */
INDIRECT_Y;
goto ins;
OPCODE(f5) /* SBC ab,x */
ZPAGE_X;
data = zGetByte(addr);
goto sbc;
OPCODE(f6) /* INC ab,x */
ZPAGE_X;
Z = N = zGetByte(addr) + 1;
dPutByte(addr, Z);
DONE
OPCODE(f7) /* INS ab,x [unofficial - INC Mem then SBC with Acc] */
ZPAGE_X;
goto ins_zpage;
OPCODE(f8) /* SED */
SetD;
DONE
OPCODE(f9) /* SBC abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
data = GetByte(addr);
goto sbc;
OPCODE(fb) /* INS abcd,y [unofficial - INC Mem then SBC with Acc] */
ABSOLUTE_Y;
goto ins;
OPCODE(fd) /* SBC abcd,x */
ABSOLUTE_X;
NCYCLES_X;
data = GetByte(addr);
goto sbc;
OPCODE(fe) /* INC abcd,x */
ABSOLUTE_X;
RMW_GetByte(Z, addr);
N = ++Z;
PutByte(addr, Z);
DONE
OPCODE(ff) /* INS abcd,x [unofficial - INC Mem then SBC with Acc] */
ABSOLUTE_X;
goto ins;
OPCODE(d2) /* ESCRTS #ab (CIM) - on Atari is here instruction CIM [unofficial] !RS! */
data = IMMEDIATE;
UPDATE_GLOBAL_REGS;
CPU_GetStatus();
Atari800_RunEsc(data);
CPU_PutStatus();
UPDATE_LOCAL_REGS;
data = PL;
SET_PC((PL << 8) + data + 1);
DONE
OPCODE(f2) /* ESC #ab (CIM) - on Atari is here instruction CIM [unofficial] !RS! */
/* OPCODE(ff: ESC #ab - opcode FF is now used for INS [unofficial] instruction !RS! */
data = IMMEDIATE;
UPDATE_GLOBAL_REGS;
CPU_GetStatus();
Atari800_RunEsc(data);
CPU_PutStatus();
UPDATE_LOCAL_REGS;
DONE
OPCODE_ALIAS(02) /* CIM [unofficial - crash intermediate] */
OPCODE_ALIAS(12)
OPCODE_ALIAS(22)
OPCODE_ALIAS(32)
OPCODE_ALIAS(42)
OPCODE_ALIAS(52)
OPCODE_ALIAS(62)
OPCODE_ALIAS(72)
OPCODE_ALIAS(92)
OPCODE(b2)
/* OPCODE(d2) Used for ESCRTS #ab (CIM) */
/* OPCODE(f2) Used for ESC #ab (CIM) */
PC--;
UPDATE_GLOBAL_REGS;
CPU_GetStatus();
// Normally we enter the monitor here... but not for this emulation
CPU_PutStatus();
UPDATE_LOCAL_REGS;
DONE
/* ---------------------------------------------- */
/* ADC and SBC routines */
adc:
if (!(regP & D_FLAG)) {
/* Binary mode */
unsigned int tmp;
tmp = A + data + C;
C = tmp > 0xff;
/* C = tmp >> 8; */
#ifndef NO_V_FLAG_VARIABLE
V = !((A ^ data) & 0x80) && ((data ^ tmp) & 0x80);
#else
ClrV;
if (!((A ^ data) & 0x80) && ((data ^ tmp) & 0x80))
SetV;
#endif
Z = N = A = (UBYTE) tmp;
}
else {
/* Decimal mode */
unsigned int tmp;
tmp = (A & 0x0f) + (data & 0x0f) + C;
if (tmp >= 10)
tmp = (tmp - 10) | 0x10;
tmp += (A & 0xf0) + (data & 0xf0);
Z = A + data + C;
N = (UBYTE) tmp;
#ifndef NO_V_FLAG_VARIABLE
V = !((A ^ data) & 0x80) && ((data ^ tmp) & 0x80);
#else
ClrV;
if (!((A ^ data) & 0x80) && ((data ^ tmp) & 0x80))
SetV;
#endif
if (tmp > 0x9f)
tmp += 0x60;
C = tmp > 0xff;
A = (UBYTE) tmp;
}
DONE
sbc:
if (!(regP & D_FLAG)) {
/* Binary mode */
unsigned int tmp;
/* tmp = A - data - !C; */
tmp = A - data - 1 + C;
C = tmp < 0x100;
#ifndef NO_V_FLAG_VARIABLE
V = ((A ^ tmp) & 0x80) && ((A ^ data) & 0x80);
#else
ClrV;
if (((A ^ tmp) & 0x80) && ((A ^ data) & 0x80))
SetV;
#endif
Z = N = A = (UBYTE) tmp;
}
else {
/* Decimal mode */
unsigned int al, ah, tmp;
/* tmp = A - data - !C; */
tmp = A - data - 1 + C;
/* al = (A & 0x0f) - (data & 0x0f) - !C; */
al = (A & 0x0f) - (data & 0x0f) - 1 + C; /* Calculate lower nybble */
ah = (A >> 4) - (data >> 4); /* Calculate upper nybble */
if (al & 0x10) {
al -= 6; /* BCD fixup for lower nybble */
ah--;
}
if (ah & 0x10)
ah -= 6; /* BCD fixup for upper nybble */
C = tmp < 0x100; /* Set flags */
#ifndef NO_V_FLAG_VARIABLE
V = ((A ^ tmp) & 0x80) && ((A ^ data) & 0x80);
#else
ClrV;
if (((A ^ tmp) & 0x80) && ((A ^ data) & 0x80))
SetV;
#endif
Z = N = (UBYTE) tmp;
A = (ah << 4) + (al & 0x0f); /* Compose result */
}
DONE
}
UPDATE_GLOBAL_REGS;
}
/* 6502 emulation routine */
#define dGetByte(x) (memory[x])
#define dPutByte(x,y) (memory[x]=y)
ITCM_CODE void GO(int limit)
{
extern UBYTE bCartIsBanked;
if (bCartIsBanked) return GO_Banked(limit); // Cart is bigger than 32K so call the CPU handler that can manage banked memory[]
#define OPCODE_ALIAS(code) opcode_##code:
#define DONE goto next;
static const void *opcode[256] __attribute__((section(".dtcm"))) =
{
&&opcode_00, &&opcode_01, &&opcode_02, &&opcode_03,
&&opcode_04, &&opcode_05, &&opcode_06, &&opcode_07,
&&opcode_08, &&opcode_09, &&opcode_0a, &&opcode_0b,
&&opcode_0c, &&opcode_0d, &&opcode_0e, &&opcode_0f,
&&opcode_10, &&opcode_11, &&opcode_12, &&opcode_13,
&&opcode_14, &&opcode_15, &&opcode_16, &&opcode_17,
&&opcode_18, &&opcode_19, &&opcode_1a, &&opcode_1b,
&&opcode_1c, &&opcode_1d, &&opcode_1e, &&opcode_1f,
&&opcode_20, &&opcode_21, &&opcode_22, &&opcode_23,
&&opcode_24, &&opcode_25, &&opcode_26, &&opcode_27,
&&opcode_28, &&opcode_29, &&opcode_2a, &&opcode_2b,
&&opcode_2c, &&opcode_2d, &&opcode_2e, &&opcode_2f,
&&opcode_30, &&opcode_31, &&opcode_32, &&opcode_33,
&&opcode_34, &&opcode_35, &&opcode_36, &&opcode_37,
&&opcode_38, &&opcode_39, &&opcode_3a, &&opcode_3b,
&&opcode_3c, &&opcode_3d, &&opcode_3e, &&opcode_3f,
&&opcode_40, &&opcode_41, &&opcode_42, &&opcode_43,
&&opcode_44, &&opcode_45, &&opcode_46, &&opcode_47,
&&opcode_48, &&opcode_49, &&opcode_4a, &&opcode_4b,
&&opcode_4c, &&opcode_4d, &&opcode_4e, &&opcode_4f,
&&opcode_50, &&opcode_51, &&opcode_52, &&opcode_53,
&&opcode_54, &&opcode_55, &&opcode_56, &&opcode_57,
&&opcode_58, &&opcode_59, &&opcode_5a, &&opcode_5b,
&&opcode_5c, &&opcode_5d, &&opcode_5e, &&opcode_5f,
&&opcode_60, &&opcode_61, &&opcode_62, &&opcode_63,
&&opcode_64, &&opcode_65, &&opcode_66, &&opcode_67,
&&opcode_68, &&opcode_69, &&opcode_6a, &&opcode_6b,
&&opcode_6c, &&opcode_6d, &&opcode_6e, &&opcode_6f,
&&opcode_70, &&opcode_71, &&opcode_72, &&opcode_73,
&&opcode_74, &&opcode_75, &&opcode_76, &&opcode_77,
&&opcode_78, &&opcode_79, &&opcode_7a, &&opcode_7b,
&&opcode_7c, &&opcode_7d, &&opcode_7e, &&opcode_7f,
&&opcode_80, &&opcode_81, &&opcode_82, &&opcode_83,
&&opcode_84, &&opcode_85, &&opcode_86, &&opcode_87,
&&opcode_88, &&opcode_89, &&opcode_8a, &&opcode_8b,
&&opcode_8c, &&opcode_8d, &&opcode_8e, &&opcode_8f,
&&opcode_90, &&opcode_91, &&opcode_92, &&opcode_93,
&&opcode_94, &&opcode_95, &&opcode_96, &&opcode_97,
&&opcode_98, &&opcode_99, &&opcode_9a, &&opcode_9b,
&&opcode_9c, &&opcode_9d, &&opcode_9e, &&opcode_9f,
&&opcode_a0, &&opcode_a1, &&opcode_a2, &&opcode_a3,
&&opcode_a4, &&opcode_a5, &&opcode_a6, &&opcode_a7,
&&opcode_a8, &&opcode_a9, &&opcode_aa, &&opcode_ab,
&&opcode_ac, &&opcode_ad, &&opcode_ae, &&opcode_af,
&&opcode_b0, &&opcode_b1, &&opcode_b2, &&opcode_b3,
&&opcode_b4, &&opcode_b5, &&opcode_b6, &&opcode_b7,
&&opcode_b8, &&opcode_b9, &&opcode_ba, &&opcode_bb,
&&opcode_bc, &&opcode_bd, &&opcode_be, &&opcode_bf,
&&opcode_c0, &&opcode_c1, &&opcode_c2, &&opcode_c3,
&&opcode_c4, &&opcode_c5, &&opcode_c6, &&opcode_c7,
&&opcode_c8, &&opcode_c9, &&opcode_ca, &&opcode_cb,
&&opcode_cc, &&opcode_cd, &&opcode_ce, &&opcode_cf,
&&opcode_d0, &&opcode_d1, &&opcode_d2, &&opcode_d3,
&&opcode_d4, &&opcode_d5, &&opcode_d6, &&opcode_d7,
&&opcode_d8, &&opcode_d9, &&opcode_da, &&opcode_db,
&&opcode_dc, &&opcode_dd, &&opcode_de, &&opcode_df,
&&opcode_e0, &&opcode_e1, &&opcode_e2, &&opcode_e3,
&&opcode_e4, &&opcode_e5, &&opcode_e6, &&opcode_e7,
&&opcode_e8, &&opcode_e9, &&opcode_ea, &&opcode_eb,
&&opcode_ec, &&opcode_ed, &&opcode_ee, &&opcode_ef,
&&opcode_f0, &&opcode_f1, &&opcode_f2, &&opcode_f3,
&&opcode_f4, &&opcode_f5, &&opcode_f6, &&opcode_f7,
&&opcode_f8, &&opcode_f9, &&opcode_fa, &&opcode_fb,
&&opcode_fc, &&opcode_fd, &&opcode_fe, &&opcode_ff,
};
#define OPCODE(code) OPCODE_ALIAS(code)
UWORD addr;
UBYTE data;
UBYTE S;
#define insn data
/*
This used to be in the main loop but has been removed to improve
execution speed. It does not seem to have any adverse effect on
the emulation for two reasons:
1. NMI's will can only be raised in antic.c - there is
no way an NMI can be generated whilst in this routine.
2. The timing of the IRQs are not that critical. */
if (wsync_halt) {
if (limit < WSYNC_C)
return;
xpos = WSYNC_C;
wsync_halt = 0;
}
xpos_limit = limit; /* needed for WSYNC store inside ANTIC */
UPDATE_LOCAL_REGS;
CPUCHECKIRQ;
// A jump to the next instruction will land us here just before the test on xpos
next:
while (xpos < xpos_limit)
{
insn = GET_CODE_BYTE();
xpos += cycles[insn];
goto *opcode[insn];
OPCODE(00) /* BRK */
PC++;
PHPC;
PHPB1;
SetI;
SET_PC(dGetWordAligned(0xfffe));
DONE
OPCODE(01) /* ORA (ab,x) */
INDIRECT_X;
ORA(GetByte(addr));
DONE
OPCODE(03) /* ASO (ab,x) [unofficial - ASL then ORA with Acc] */
INDIRECT_X;
aso:
RMW_GetByte(data, addr);
C = (data & 0x80) ? 1 : 0;
data <<= 1;
PutByte(addr, data);
Z = N = A |= data;
DONE
OPCODE_ALIAS(04) /* NOP ab [unofficial - skip byte] */
OPCODE_ALIAS(44)
OPCODE(64)
PC++;
DONE
OPCODE_ALIAS(14) /* NOP ab,x [unofficial - skip byte] */
OPCODE_ALIAS(34)
OPCODE_ALIAS(54)
OPCODE_ALIAS(74)
OPCODE_ALIAS(d4)
OPCODE(f4)
PC++;
DONE
OPCODE_ALIAS(80) /* NOP #ab [unofficial - skip byte] */
OPCODE_ALIAS(82)
OPCODE_ALIAS(89)
OPCODE_ALIAS(c2)
OPCODE(e2)
PC++;
DONE
OPCODE(05) /* ORA ab */
ZPAGE;
ORA(dGetByte(addr));
DONE
OPCODE(06) /* ASL ab */
ZPAGE;
data = dGetByte(addr);
C = (data & 0x80) ? 1 : 0;
Z = N = data << 1;
dPutByte(addr, Z);
DONE
OPCODE(07) /* ASO ab [unofficial - ASL then ORA with Acc] */
ZPAGE;
aso_zpage:
data = dGetByte(addr);
C = (data & 0x80) ? 1 : 0;
data <<= 1;
dPutByte(addr, data);
Z = N = A |= data;
DONE
OPCODE(08) /* PHP */
PHPB1;
DONE
OPCODE(09) /* ORA #ab */
ORA(IMMEDIATE);
DONE
OPCODE(0a) /* ASL */
C = (A & 0x80) ? 1 : 0;
Z = N = A <<= 1;
DONE
OPCODE_ALIAS(0b) /* ANC #ab [unofficial - AND then copy N to C (Fox) */
OPCODE(2b)
AND(IMMEDIATE);
C = N >= 0x80;
DONE
OPCODE(0c) /* NOP abcd [unofficial - skip word] */
PC += 2;
DONE
OPCODE(0d) /* ORA abcd */
ABSOLUTE;
ORA(GetByte(addr));
DONE
OPCODE(0e) /* ASL abcd */
ABSOLUTE;
RMW_GetByte(data, addr);
C = (data & 0x80) ? 1 : 0;
Z = N = data << 1;
PutByte(addr, Z);
DONE
OPCODE(0f) /* ASO abcd [unofficial - ASL then ORA with Acc] */
ABSOLUTE;
goto aso;
OPCODE(10) /* BPL */
BRANCH(!(N & 0x80))
OPCODE(11) /* ORA (ab),y */
INDIRECT_Y;
NCYCLES_Y;
ORA(GetByte(addr));
DONE
OPCODE(13) /* ASO (ab),y [unofficial - ASL then ORA with Acc] */
INDIRECT_Y;
goto aso;
OPCODE(15) /* ORA ab,x */
ZPAGE_X;
ORA(zGetByte(addr));
DONE
OPCODE(16) /* ASL ab,x */
ZPAGE_X;
data = zGetByte(addr);
C = (data & 0x80) ? 1 : 0;
Z = N = data << 1;
dPutByte(addr, Z);
DONE
OPCODE(17) /* ASO ab,x [unofficial - ASL then ORA with Acc] */
ZPAGE_X;
goto aso_zpage;
OPCODE(18) /* CLC */
C = 0;
DONE
OPCODE(19) /* ORA abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
ORA(GetByte(addr));
DONE
OPCODE(1b) /* ASO abcd,y [unofficial - ASL then ORA with Acc] */
ABSOLUTE_Y;
goto aso;
OPCODE_ALIAS(1c) /* NOP abcd,x [unofficial - skip word] */
OPCODE_ALIAS(3c)
OPCODE_ALIAS(5c)
OPCODE_ALIAS(7c)
OPCODE_ALIAS(dc)
OPCODE(fc)
if (OP_BYTE + X >= 0x100)
xpos++;
PC += 2;
DONE
OPCODE(1d) /* ORA abcd,x */
ABSOLUTE_X;
NCYCLES_X;
ORA(GetByte(addr));
DONE
OPCODE(1e) /* ASL abcd,x */
ABSOLUTE_X;
RMW_GetByte(data, addr);
C = (data & 0x80) ? 1 : 0;
Z = N = data << 1;
PutByte(addr, Z);
DONE
OPCODE(1f) /* ASO abcd,x [unofficial - ASL then ORA with Acc] */
ABSOLUTE_X;
goto aso;
OPCODE(20) /* JSR abcd */
{
UWORD retaddr = GET_PC() + 1;
PHW(retaddr);
}
SET_PC(OP_WORD);
DONE
OPCODE(21) /* AND (ab,x) */
INDIRECT_X;
AND(GetByte(addr));
DONE
OPCODE(23) /* RLA (ab,x) [unofficial - ROL Mem, then AND with A] */
INDIRECT_X;
rla:
RMW_GetByte(data, addr);
if (C) {
C = (data & 0x80) ? 1 : 0;
data = (data << 1) + 1;
}
else {
C = (data & 0x80) ? 1 : 0;
data = (data << 1);
}
PutByte(addr, data);
Z = N = A &= data;
DONE
OPCODE(24) /* BIT ab */
ZPAGE;
N = dGetByte(addr);
#ifndef NO_V_FLAG_VARIABLE
V = N & 0x40;
#else
regP = (regP & 0xbf) + (N & 0x40);
#endif
Z = (A & N);
DONE
OPCODE(25) /* AND ab */
ZPAGE;
AND(dGetByte(addr));
DONE
OPCODE(26) /* ROL ab */
ZPAGE;
data = dGetByte(addr);
Z = N = (data << 1) + C;
C = (data & 0x80) ? 1 : 0;
dPutByte(addr, Z);
DONE
OPCODE(27) /* RLA ab [unofficial - ROL Mem, then AND with A] */
ZPAGE;
rla_zpage:
data = dGetByte(addr);
if (C) {
C = (data & 0x80) ? 1 : 0;
data = (data << 1) + 1;
}
else {
C = (data & 0x80) ? 1 : 0;
data = (data << 1);
}
dPutByte(addr, data);
Z = N = A &= data;
DONE
OPCODE(28) /* PLP */
PLP;
CPUCHECKIRQ;
DONE
OPCODE(29) /* AND #ab */
AND(IMMEDIATE);
DONE
OPCODE(2a) /* ROL */
Z = N = (A << 1) + C;
C = (A & 0x80) ? 1 : 0;
A = Z;
DONE
OPCODE(2c) /* BIT abcd */
ABSOLUTE;
N = GetByte(addr);
#ifndef NO_V_FLAG_VARIABLE
V = N & 0x40;
#else
regP = (regP & 0xbf) + (N & 0x40);
#endif
Z = (A & N);
DONE
OPCODE(2d) /* AND abcd */
ABSOLUTE;
AND(GetByte(addr));
DONE
OPCODE(2e) /* ROL abcd */
ABSOLUTE;
RMW_GetByte(data, addr);
Z = N = (data << 1) + C;
C = (data & 0x80) ? 1 : 0;
PutByte(addr, Z);
DONE
OPCODE(2f) /* RLA abcd [unofficial - ROL Mem, then AND with A] */
ABSOLUTE;
goto rla;
OPCODE(30) /* BMI */
BRANCH(N & 0x80)
OPCODE(31) /* AND (ab),y */
INDIRECT_Y;
NCYCLES_Y;
AND(GetByte(addr));
DONE
OPCODE(33) /* RLA (ab),y [unofficial - ROL Mem, then AND with A] */
INDIRECT_Y;
goto rla;
OPCODE(35) /* AND ab,x */
ZPAGE_X;
AND(zGetByte(addr));
DONE
OPCODE(36) /* ROL ab,x */
ZPAGE_X;
data = zGetByte(addr);
Z = N = (data << 1) + C;
C = (data & 0x80) ? 1 : 0;
dPutByte(addr, Z);
DONE
OPCODE(37) /* RLA ab,x [unofficial - ROL Mem, then AND with A] */
ZPAGE_X;
goto rla_zpage;
OPCODE(38) /* SEC */
C = 1;
DONE
OPCODE(39) /* AND abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
AND(GetByte(addr));
DONE
OPCODE(3b) /* RLA abcd,y [unofficial - ROL Mem, then AND with A] */
ABSOLUTE_Y;
goto rla;
OPCODE(3d) /* AND abcd,x */
ABSOLUTE_X;
NCYCLES_X;
AND(GetByte(addr));
DONE
OPCODE(3e) /* ROL abcd,x */
ABSOLUTE_X;
RMW_GetByte(data, addr);
Z = N = (data << 1) + C;
C = (data & 0x80) ? 1 : 0;
PutByte(addr, Z);
DONE
OPCODE(3f) /* RLA abcd,x [unofficial - ROL Mem, then AND with A] */
ABSOLUTE_X;
goto rla;
OPCODE(40) /* RTI */
PLP;
data = PL;
SET_PC((PL << 8) + data);
CPUCHECKIRQ;
DONE
OPCODE(41) /* EOR (ab,x) */
INDIRECT_X;
EOR(GetByte(addr));
DONE
OPCODE(43) /* LSE (ab,x) [unofficial - LSR then EOR result with A] */
INDIRECT_X;
lse:
RMW_GetByte(data, addr);
C = data & 1;
data >>= 1;
PutByte(addr, data);
Z = N = A ^= data;
DONE
OPCODE(45) /* EOR ab */
ZPAGE;
EOR(dGetByte(addr));
DONE
OPCODE(46) /* LSR ab */
ZPAGE;
data = dGetByte(addr);
C = data & 1;
Z = data >> 1;
N = 0;
dPutByte(addr, Z);
DONE
OPCODE(47) /* LSE ab [unofficial - LSR then EOR result with A] */
ZPAGE;
lse_zpage:
data = dGetByte(addr);
C = data & 1;
data >>= 1;
dPutByte(addr, data);
Z = N = A ^= data;
DONE
OPCODE(48) /* PHA */
PH(A);
DONE
OPCODE(49) /* EOR #ab */
EOR(IMMEDIATE);
DONE
OPCODE(4a) /* LSR */
C = A & 1;
Z = N = A >>= 1;
DONE
OPCODE(4b) /* ALR #ab [unofficial - Acc AND Data, LSR result] */
data = A & IMMEDIATE;
C = data & 1;
Z = N = A = (data >> 1);
DONE
OPCODE(4c) /* JMP abcd */
SET_PC(OP_WORD);
DONE
OPCODE(4d) /* EOR abcd */
ABSOLUTE;
EOR(GetByte(addr));
DONE
OPCODE(4e) /* LSR abcd */
ABSOLUTE;
RMW_GetByte(data, addr);
C = data & 1;
Z = data >> 1;
N = 0;
PutByte(addr, Z);
DONE
OPCODE(4f) /* LSE abcd [unofficial - LSR then EOR result with A] */
ABSOLUTE;
goto lse;
OPCODE(50) /* BVC */
#ifndef NO_V_FLAG_VARIABLE
BRANCH(!V)
#else
BRANCH(!(regP & 0x40))
#endif
OPCODE(51) /* EOR (ab),y */
INDIRECT_Y;
NCYCLES_Y;
EOR(GetByte(addr));
DONE
OPCODE(53) /* LSE (ab),y [unofficial - LSR then EOR result with A] */
INDIRECT_Y;
goto lse;
OPCODE(55) /* EOR ab,x */
ZPAGE_X;
EOR(zGetByte(addr));
DONE
OPCODE(56) /* LSR ab,x */
ZPAGE_X;
data = zGetByte(addr);
C = data & 1;
Z = data >> 1;
N = 0;
dPutByte(addr, Z);
DONE
OPCODE(57) /* LSE ab,x [unofficial - LSR then EOR result with A] */
ZPAGE_X;
goto lse_zpage;
OPCODE(58) /* CLI */
ClrI;
CPUCHECKIRQ;
DONE
OPCODE(59) /* EOR abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
EOR(GetByte(addr));
DONE
OPCODE(5b) /* LSE abcd,y [unofficial - LSR then EOR result with A] */
ABSOLUTE_Y;
goto lse;
OPCODE(5d) /* EOR abcd,x */
ABSOLUTE_X;
NCYCLES_X;
EOR(GetByte(addr));
DONE
OPCODE(5e) /* LSR abcd,x */
ABSOLUTE_X;
RMW_GetByte(data, addr);
C = data & 1;
Z = data >> 1;
N = 0;
PutByte(addr, Z);
DONE
OPCODE(5f) /* LSE abcd,x [unofficial - LSR then EOR result with A] */
ABSOLUTE_X;
goto lse;
OPCODE(60) /* RTS */
data = PL;
SET_PC((PL << 8) + data + 1);
DONE
OPCODE(61) /* ADC (ab,x) */
INDIRECT_X;
data = GetByte(addr);
goto adc;
OPCODE(63) /* RRA (ab,x) [unofficial - ROR Mem, then ADC to Acc] */
INDIRECT_X;
rra:
RMW_GetByte(data, addr);
if (C) {
C = data & 1;
data = (data >> 1) + 0x80;
}
else {
C = data & 1;
data >>= 1;
}
PutByte(addr, data);
goto adc;
OPCODE(65) /* ADC ab */
ZPAGE;
data = zGetByte(addr);
goto adc;
OPCODE(66) /* ROR ab */
ZPAGE;
data = zGetByte(addr);
Z = N = (C << 7) + (data >> 1);
C = data & 1;
dPutByte(addr, Z);
DONE
OPCODE(67) /* RRA ab [unofficial - ROR Mem, then ADC to Acc] */
ZPAGE;
rra_zpage:
data = zGetByte(addr);
if (C) {
C = data & 1;
data = (data >> 1) + 0x80;
}
else {
C = data & 1;
data >>= 1;
}
dPutByte(addr, data);
goto adc;
OPCODE(68) /* PLA */
Z = N = A = PL;
DONE
OPCODE(69) /* ADC #ab */
data = IMMEDIATE;
goto adc;
OPCODE(6a) /* ROR */
Z = N = (C << 7) + (A >> 1);
C = A & 1;
A = Z;
DONE
OPCODE(6b) /* ARR #ab [unofficial - Acc AND Data, ROR result] */
/* It does some 'BCD fixup' if D flag is set */
/* MPC 05/24/00 */
data = A & IMMEDIATE;
if (regP & D_FLAG) {
UBYTE temp = (data >> 1) + (C << 7);
Z = N = temp;
#ifndef NO_V_FLAG_VARIABLE
V = ((temp ^ data) & 0x40);
#else
regP = (regP & 0xbf) + ((temp ^ data) & 0x40);
#endif
if ((data & 0x0F) + (data & 0x01) > 5)
temp = (temp & 0xF0) + ((temp + 0x6) & 0x0F);
if (data + (data & 0x10) >= 0x60) {
temp += 0x60;
C = 1;
}
else
C = 0;
A = (UBYTE) temp;
}
else {
Z = N = A = (data >> 1) + (C << 7);
C = data >> 7;
#ifndef NO_V_FLAG_VARIABLE
V = C ^ ((A >> 5) & 1);
#else
regP = (regP & 0xbf) + ((A ^ data) & 0x40);
#endif
}
DONE
OPCODE(6c) /* JMP (abcd) */
ABSOLUTE;
#ifdef CPU65C02
/* XXX: if ((UBYTE) addr == 0xff) xpos++; */
SET_PC(dGetWord(addr));
#else
/* original 6502 had a bug in JMP (addr) when addr crossed page boundary */
if ((UBYTE) addr == 0xff)
SET_PC((dGetByte(addr - 0xff) << 8) + dGetByte(addr));
else
SET_PC(dGetWord(addr));
#endif
DONE
OPCODE(6d) /* ADC abcd */
ABSOLUTE;
data = GetByte(addr);
goto adc;
OPCODE(6e) /* ROR abcd */
ABSOLUTE;
RMW_GetByte(data, addr);
Z = N = (C << 7) + (data >> 1);
C = data & 1;
PutByte(addr, Z);
DONE
OPCODE(6f) /* RRA abcd [unofficial - ROR Mem, then ADC to Acc] */
ABSOLUTE;
goto rra;
OPCODE(70) /* BVS */
#ifndef NO_V_FLAG_VARIABLE
BRANCH(V)
#else
BRANCH(regP & 0x40)
#endif
OPCODE(71) /* ADC (ab),y */
INDIRECT_Y;
NCYCLES_Y;
data = GetByte(addr);
goto adc;
OPCODE(73) /* RRA (ab),y [unofficial - ROR Mem, then ADC to Acc] */
INDIRECT_Y;
goto rra;
OPCODE(75) /* ADC ab,x */
ZPAGE_X;
data = zGetByte(addr);
goto adc;
OPCODE(76) /* ROR ab,x */
ZPAGE_X;
data = zGetByte(addr);
Z = N = (C << 7) + (data >> 1);
C = data & 1;
dPutByte(addr, Z);
DONE
OPCODE(77) /* RRA ab,x [unofficial - ROR Mem, then ADC to Acc] */
ZPAGE_X;
goto rra_zpage;
OPCODE(78) /* SEI */
SetI;
DONE
OPCODE(79) /* ADC abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
data = GetByte(addr);
goto adc;
OPCODE(7b) /* RRA abcd,y [unofficial - ROR Mem, then ADC to Acc] */
ABSOLUTE_Y;
goto rra;
OPCODE(7d) /* ADC abcd,x */
ABSOLUTE_X;
NCYCLES_X;
data = GetByte(addr);
goto adc;
OPCODE(7e) /* ROR abcd,x */
ABSOLUTE_X;
RMW_GetByte(data, addr);
Z = N = (C << 7) + (data >> 1);
C = data & 1;
PutByte(addr, Z);
DONE
OPCODE(7f) /* RRA abcd,x [unofficial - ROR Mem, then ADC to Acc] */
ABSOLUTE_X;
goto rra;
OPCODE(81) /* STA (ab,x) */
INDIRECT_X;
PutByte(addr, A);
DONE
/* AXS doesn't change flags and SAX is better name for it (Fox) */
OPCODE(83) /* SAX (ab,x) [unofficial - Store result A AND X */
INDIRECT_X;
data = A & X;
PutByte(addr, data);
DONE
OPCODE(84) /* STY ab */
ZPAGE;
dPutByte(addr, Y);
DONE
OPCODE(85) /* STA ab */
ZPAGE;
dPutByte(addr, A);
DONE
OPCODE(86) /* STX ab */
ZPAGE;
dPutByte(addr, X);
DONE
OPCODE(87) /* SAX ab [unofficial - Store result A AND X] */
ZPAGE;
data = A & X;
dPutByte(addr, data);
DONE
OPCODE(88) /* DEY */
Z = N = --Y;
DONE
OPCODE(8a) /* TXA */
Z = N = A = X;
DONE
OPCODE(8b) /* ANE #ab [unofficial - A AND X AND (Mem OR $EF) to Acc] (Fox) */
data = IMMEDIATE;
N = Z = A & X & data;
A &= X & (data | 0xef);
DONE
OPCODE(8c) /* STY abcd */
ABSOLUTE;
PutByte(addr, Y);
DONE
OPCODE(8d) /* STA abcd */
ABSOLUTE;
PutByte(addr, A);
DONE
OPCODE(8e) /* STX abcd */
ABSOLUTE;
PutByte(addr, X);
DONE
OPCODE(8f) /* SAX abcd [unofficial - Store result A AND X] */
ABSOLUTE;
data = A & X;
PutByte(addr, data);
DONE
OPCODE(90) /* BCC */
BRANCH(!C)
OPCODE(91) /* STA (ab),y */
INDIRECT_Y;
PutByte(addr, A);
DONE
OPCODE(93) /* SHA (ab),y [unofficial, UNSTABLE - Store A AND X AND (H+1) ?] (Fox) */
/* It seems previous memory value is important - also in 9f */
ZPAGE;
data = zGetByte((UBYTE) (addr + 1)); /* Get high byte from zpage */
data = A & X & (data + 1);
addr = dGetWord(addr) + Y;
PutByte(addr, data);
DONE
OPCODE(94) /* STY ab,x */
ZPAGE_X;
dPutByte(addr, Y);
DONE
OPCODE(95) /* STA ab,x */
ZPAGE_X;
dPutByte(addr, A);
DONE
OPCODE(96) /* STX ab,y */
ZPAGE_Y;
dPutByte(addr, X);
DONE
OPCODE(97) /* SAX ab,y [unofficial - Store result A AND X] */
ZPAGE_Y;
data = A & X;
dPutByte(addr, data);
DONE
OPCODE(98) /* TYA */
Z = N = A = Y;
DONE
OPCODE(99) /* STA abcd,y */
ABSOLUTE_Y;
PutByte(addr, A);
DONE
OPCODE(9a) /* TXS */
S = X;
DONE
OPCODE(9b) /* SHS abcd,y [unofficial, UNSTABLE] (Fox) */
/* Transfer A AND X to S, then store S AND (H+1)] */
/* S seems to be stable, only memory values vary */
ABSOLUTE;
S = A & X;
data = S & ((addr >> 8) + 1);
addr += Y;
PutByte(addr, data);
DONE
OPCODE(9c) /* SHY abcd,x [unofficial - Store Y and (H+1)] (Fox) */
/* Seems to be stable */
ABSOLUTE;
/* MPC 05/24/00 */
data = Y & ((UBYTE) ((addr >> 8) + 1));
addr += X;
PutByte(addr, data);
DONE
OPCODE(9d) /* STA abcd,x */
ABSOLUTE_X;
PutByte(addr, A);
DONE
OPCODE(9e) /* SHX abcd,y [unofficial - Store X and (H+1)] (Fox) */
/* Seems to be stable */
ABSOLUTE;
/* MPC 05/24/00 */
data = X & ((UBYTE) ((addr >> 8) + 1));
addr += Y;
PutByte(addr, data);
DONE
OPCODE(9f) /* SHA abcd,y [unofficial, UNSTABLE - Store A AND X AND (H+1) ?] (Fox) */
ABSOLUTE;
data = A & X & ((addr >> 8) + 1);
addr += Y;
PutByte(addr, data);
DONE
OPCODE(a0) /* LDY #ab */
LDY(IMMEDIATE);
DONE
OPCODE(a1) /* LDA (ab,x) */
INDIRECT_X;
LDA(GetByte(addr));
DONE
OPCODE(a2) /* LDX #ab */
LDX(IMMEDIATE);
DONE
OPCODE(a3) /* LAX (ab,x) [unofficial] */
INDIRECT_X;
Z = N = X = A = GetByte(addr);
DONE
OPCODE(a4) /* LDY ab */
ZPAGE;
LDY(zGetByte(addr));
DONE
OPCODE(a5) /* LDA ab */
ZPAGE;
LDA(zGetByte(addr));
DONE
OPCODE(a6) /* LDX ab */
ZPAGE;
LDX(zGetByte(addr));
DONE
OPCODE(a7) /* LAX ab [unofficial] */
ZPAGE;
Z = N = X = A = zGetByte(addr);
DONE
OPCODE(a8) /* TAY */
Z = N = Y = A;
DONE
OPCODE(a9) /* LDA #ab */
LDA(IMMEDIATE);
DONE
OPCODE(aa) /* TAX */
Z = N = X = A;
DONE
OPCODE(ab) /* ANX #ab [unofficial - AND #ab, then TAX] */
Z = N = X = A &= IMMEDIATE;
DONE
OPCODE(ac) /* LDY abcd */
ABSOLUTE;
LDY(GetByte(addr));
DONE
OPCODE(ad) /* LDA abcd */
ABSOLUTE;
LDA(GetByte(addr));
DONE
OPCODE(ae) /* LDX abcd */
ABSOLUTE;
LDX(GetByte(addr));
DONE
OPCODE(af) /* LAX abcd [unofficial] */
ABSOLUTE;
Z = N = X = A = GetByte(addr);
DONE
OPCODE(b0) /* BCS */
BRANCH(C)
OPCODE(b1) /* LDA (ab),y */
INDIRECT_Y;
NCYCLES_Y;
LDA(GetByte(addr));
DONE
OPCODE(b3) /* LAX (ab),y [unofficial] */
INDIRECT_Y;
NCYCLES_Y;
Z = N = X = A = GetByte(addr);
DONE
OPCODE(b4) /* LDY ab,x */
ZPAGE_X;
LDY(zGetByte(addr));
DONE
OPCODE(b5) /* LDA ab,x */
ZPAGE_X;
LDA(zGetByte(addr));
DONE
OPCODE(b6) /* LDX ab,y */
ZPAGE_Y;
LDX(zGetByte(addr));
DONE
OPCODE(b7) /* LAX ab,y [unofficial] */
ZPAGE_Y;
Z = N = X = A = zGetByte(addr);
DONE
OPCODE(b8) /* CLV */
#ifndef NO_V_FLAG_VARIABLE
V = 0;
#else
ClrV;
#endif
DONE
OPCODE(b9) /* LDA abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
LDA(GetByte(addr));
DONE
OPCODE(ba) /* TSX */
Z = N = X = S;
DONE
/* AXA [unofficial - original decode by R.Sterba and R.Petruzela 15.1.1998 :-)]
AXA - this is our new imaginative name for instruction with opcode hex BB.
AXA - Store Mem AND #$FD to Acc and X, then set stackpoint to value (Acc - 4)
It's cool! :-)
LAS - this is better name for this :) (Fox)
It simply ANDs stack pointer with Mem, then transfers result to A and X
*/
OPCODE(bb) /* LAS abcd,y [unofficial - AND S with Mem, transfer to A and X (Fox) */
ABSOLUTE_Y;
NCYCLES_Y;
Z = N = A = X = S &= GetByte(addr);
DONE
OPCODE(bc) /* LDY abcd,x */
ABSOLUTE_X;
NCYCLES_X;
LDY(GetByte(addr));
DONE
OPCODE(bd) /* LDA abcd,x */
ABSOLUTE_X;
NCYCLES_X;
LDA(GetByte(addr));
DONE
OPCODE(be) /* LDX abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
LDX(GetByte(addr));
DONE
OPCODE(bf) /* LAX abcd,y [unofficial] */
ABSOLUTE_Y;
NCYCLES_Y;
Z = N = X = A = GetByte(addr);
DONE
OPCODE(c0) /* CPY #ab */
CPY(IMMEDIATE);
DONE
OPCODE(c1) /* CMP (ab,x) */
INDIRECT_X;
CMP(GetByte(addr));
DONE
OPCODE(c3) /* DCM (ab,x) [unofficial - DEC Mem then CMP with Acc] */
INDIRECT_X;
dcm:
RMW_GetByte(data, addr);
data--;
PutByte(addr, data);
CMP(data);
DONE
OPCODE(c4) /* CPY ab */
ZPAGE;
CPY(zGetByte(addr));
DONE
OPCODE(c5) /* CMP ab */
ZPAGE;
CMP(zGetByte(addr));
DONE
OPCODE(c6) /* DEC ab */
ZPAGE;
Z = N = zGetByte(addr) - 1;
dPutByte(addr, Z);
DONE
OPCODE(c7) /* DCM ab [unofficial - DEC Mem then CMP with Acc] */
ZPAGE;
dcm_zpage:
data = zGetByte(addr) - 1;
dPutByte(addr, data);
CMP(data);
DONE
OPCODE(c8) /* INY */
Z = N = ++Y;
DONE
OPCODE(c9) /* CMP #ab */
CMP(IMMEDIATE);
DONE
OPCODE(ca) /* DEX */
Z = N = --X;
DONE
OPCODE(cb) /* SBX #ab [unofficial - store ((A AND X) - Mem) in X] (Fox) */
X &= A;
data = IMMEDIATE;
C = X >= data;
/* MPC 05/24/00 */
Z = N = X -= data;
DONE
OPCODE(cc) /* CPY abcd */
ABSOLUTE;
CPY(GetByte(addr));
DONE
OPCODE(cd) /* CMP abcd */
ABSOLUTE;
CMP(GetByte(addr));
DONE
OPCODE(ce) /* DEC abcd */
ABSOLUTE;
RMW_GetByte(Z, addr);
N = --Z;
PutByte(addr, Z);
DONE
OPCODE(cf) /* DCM abcd [unofficial - DEC Mem then CMP with Acc] */
ABSOLUTE;
goto dcm;
OPCODE(d0) /* BNE */
BRANCH(Z)
OPCODE(d1) /* CMP (ab),y */
INDIRECT_Y;
NCYCLES_Y;
CMP(GetByte(addr));
DONE
OPCODE(d3) /* DCM (ab),y [unofficial - DEC Mem then CMP with Acc] */
INDIRECT_Y;
goto dcm;
OPCODE(d5) /* CMP ab,x */
ZPAGE_X;
CMP(zGetByte(addr));
Z = N = A - data;
C = (A >= data);
DONE
OPCODE(d6) /* DEC ab,x */
ZPAGE_X;
Z = N = zGetByte(addr) - 1;
dPutByte(addr, Z);
DONE
OPCODE(d7) /* DCM ab,x [unofficial - DEC Mem then CMP with Acc] */
ZPAGE_X;
goto dcm_zpage;
OPCODE(d8) /* CLD */
ClrD;
DONE
OPCODE(d9) /* CMP abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
CMP(GetByte(addr));
DONE
OPCODE(db) /* DCM abcd,y [unofficial - DEC Mem then CMP with Acc] */
ABSOLUTE_Y;
goto dcm;
OPCODE(dd) /* CMP abcd,x */
ABSOLUTE_X;
NCYCLES_X;
CMP(GetByte(addr));
DONE
OPCODE(de) /* DEC abcd,x */
ABSOLUTE_X;
RMW_GetByte(Z, addr);
N = --Z;
PutByte(addr, Z);
DONE
OPCODE(df) /* DCM abcd,x [unofficial - DEC Mem then CMP with Acc] */
ABSOLUTE_X;
goto dcm;
OPCODE(e0) /* CPX #ab */
CPX(IMMEDIATE);
DONE
OPCODE(e1) /* SBC (ab,x) */
INDIRECT_X;
data = GetByte(addr);
goto sbc;
OPCODE(e3) /* INS (ab,x) [unofficial - INC Mem then SBC with Acc] */
INDIRECT_X;
ins:
RMW_GetByte(data, addr);
++data;
PutByte(addr, data);
goto sbc;
OPCODE(e4) /* CPX ab */
ZPAGE;
CPX(zGetByte(addr));
DONE
OPCODE(e5) /* SBC ab */
ZPAGE;
data = zGetByte(addr);
goto sbc;
OPCODE(e6) /* INC ab */
ZPAGE;
Z = N = zGetByte(addr) + 1;
dPutByte(addr, Z);
DONE
OPCODE(e7) /* INS ab [unofficial - INC Mem then SBC with Acc] */
ZPAGE;
ins_zpage:
data = zGetByte(addr) + 1;
dPutByte(addr, data);
goto sbc;
OPCODE(e8) /* INX */
Z = N = ++X;
DONE
OPCODE_ALIAS(e9) /* SBC #ab */
OPCODE(eb) /* SBC #ab [unofficial] */
data = IMMEDIATE;
goto sbc;
OPCODE_ALIAS(ea) /* NOP */
OPCODE_ALIAS(1a) /* NOP [unofficial] */
OPCODE_ALIAS(3a)
OPCODE_ALIAS(5a)
OPCODE_ALIAS(7a)
OPCODE_ALIAS(da)
OPCODE(fa)
DONE
OPCODE(ec) /* CPX abcd */
ABSOLUTE;
CPX(GetByte(addr));
DONE
OPCODE(ed) /* SBC abcd */
ABSOLUTE;
data = GetByte(addr);
goto sbc;
OPCODE(ee) /* INC abcd */
ABSOLUTE;
RMW_GetByte(Z, addr);
N = ++Z;
PutByte(addr, Z);
DONE
OPCODE(ef) /* INS abcd [unofficial - INC Mem then SBC with Acc] */
ABSOLUTE;
goto ins;
OPCODE(f0) /* BEQ */
BRANCH(!Z)
OPCODE(f1) /* SBC (ab),y */
INDIRECT_Y;
NCYCLES_Y;
data = GetByte(addr);
goto sbc;
OPCODE(f3) /* INS (ab),y [unofficial - INC Mem then SBC with Acc] */
INDIRECT_Y;
goto ins;
OPCODE(f5) /* SBC ab,x */
ZPAGE_X;
data = zGetByte(addr);
goto sbc;
OPCODE(f6) /* INC ab,x */
ZPAGE_X;
Z = N = zGetByte(addr) + 1;
dPutByte(addr, Z);
DONE
OPCODE(f7) /* INS ab,x [unofficial - INC Mem then SBC with Acc] */
ZPAGE_X;
goto ins_zpage;
OPCODE(f8) /* SED */
SetD;
DONE
OPCODE(f9) /* SBC abcd,y */
ABSOLUTE_Y;
NCYCLES_Y;
data = GetByte(addr);
goto sbc;
OPCODE(fb) /* INS abcd,y [unofficial - INC Mem then SBC with Acc] */
ABSOLUTE_Y;
goto ins;
OPCODE(fd) /* SBC abcd,x */
ABSOLUTE_X;
NCYCLES_X;
data = GetByte(addr);
goto sbc;
OPCODE(fe) /* INC abcd,x */
ABSOLUTE_X;
RMW_GetByte(Z, addr);
N = ++Z;
PutByte(addr, Z);
DONE
OPCODE(ff) /* INS abcd,x [unofficial - INC Mem then SBC with Acc] */
ABSOLUTE_X;
goto ins;
OPCODE(d2) /* ESCRTS #ab (CIM) - on Atari is here instruction CIM [unofficial] !RS! */
data = IMMEDIATE;
UPDATE_GLOBAL_REGS;
CPU_GetStatus();
Atari800_RunEsc(data);
CPU_PutStatus();
UPDATE_LOCAL_REGS;
data = PL;
SET_PC((PL << 8) + data + 1);
DONE
OPCODE(f2) /* ESC #ab (CIM) - on Atari is here instruction CIM [unofficial] !RS! */
/* OPCODE(ff: ESC #ab - opcode FF is now used for INS [unofficial] instruction !RS! */
data = IMMEDIATE;
UPDATE_GLOBAL_REGS;
CPU_GetStatus();
Atari800_RunEsc(data);
CPU_PutStatus();
UPDATE_LOCAL_REGS;
DONE
OPCODE_ALIAS(02) /* CIM [unofficial - crash intermediate] */
OPCODE_ALIAS(12)
OPCODE_ALIAS(22)
OPCODE_ALIAS(32)
OPCODE_ALIAS(42)
OPCODE_ALIAS(52)
OPCODE_ALIAS(62)
OPCODE_ALIAS(72)
OPCODE_ALIAS(92)
OPCODE(b2)
/* OPCODE(d2) Used for ESCRTS #ab (CIM) */
/* OPCODE(f2) Used for ESC #ab (CIM) */
PC--;
UPDATE_GLOBAL_REGS;
CPU_GetStatus();
// Normally we enter monitor here... but not for this emulation.
CPU_PutStatus();
UPDATE_LOCAL_REGS;
DONE
/* ---------------------------------------------- */
/* ADC and SBC routines */
adc:
if (!(regP & D_FLAG)) {
/* Binary mode */
unsigned int tmp;
tmp = A + data + C;
C = tmp > 0xff;
/* C = tmp >> 8; */
#ifndef NO_V_FLAG_VARIABLE
V = !((A ^ data) & 0x80) && ((data ^ tmp) & 0x80);
#else
ClrV;
if (!((A ^ data) & 0x80) && ((data ^ tmp) & 0x80))
SetV;
#endif
Z = N = A = (UBYTE) tmp;
}
else {
/* Decimal mode */
unsigned int tmp;
tmp = (A & 0x0f) + (data & 0x0f) + C;
if (tmp >= 10)
tmp = (tmp - 10) | 0x10;
tmp += (A & 0xf0) + (data & 0xf0);
Z = A + data + C;
N = (UBYTE) tmp;
#ifndef NO_V_FLAG_VARIABLE
V = !((A ^ data) & 0x80) && ((data ^ tmp) & 0x80);
#else
ClrV;
if (!((A ^ data) & 0x80) && ((data ^ tmp) & 0x80))
SetV;
#endif
if (tmp > 0x9f)
tmp += 0x60;
C = tmp > 0xff;
A = (UBYTE) tmp;
}
DONE
sbc:
if (!(regP & D_FLAG)) {
/* Binary mode */
unsigned int tmp;
/* tmp = A - data - !C; */
tmp = A - data - 1 + C;
C = tmp < 0x100;
#ifndef NO_V_FLAG_VARIABLE
V = ((A ^ tmp) & 0x80) && ((A ^ data) & 0x80);
#else
ClrV;
if (((A ^ tmp) & 0x80) && ((A ^ data) & 0x80))
SetV;
#endif
Z = N = A = (UBYTE) tmp;
}
else {
/* Decimal mode */
unsigned int al, ah, tmp;
/* tmp = A - data - !C; */
tmp = A - data - 1 + C;
/* al = (A & 0x0f) - (data & 0x0f) - !C; */
al = (A & 0x0f) - (data & 0x0f) - 1 + C; /* Calculate lower nybble */
ah = (A >> 4) - (data >> 4); /* Calculate upper nybble */
if (al & 0x10) {
al -= 6; /* BCD fixup for lower nybble */
ah--;
}
if (ah & 0x10)
ah -= 6; /* BCD fixup for upper nybble */
C = tmp < 0x100; /* Set flags */
#ifndef NO_V_FLAG_VARIABLE
V = ((A ^ tmp) & 0x80) && ((A ^ data) & 0x80);
#else
ClrV;
if (((A ^ tmp) & 0x80) && ((A ^ data) & 0x80))
SetV;
#endif
Z = N = (UBYTE) tmp;
A = (ah << 4) + (al & 0x0f); /* Compose result */
}
DONE
}
UPDATE_GLOBAL_REGS;
}
void CPU_Initialise(void)
{
}
void CPU_Reset(void)
{
IRQ = 0;
regP = 0x34; /* The unused bit is always 1, I flag set! */
CPU_PutStatus(); /* Make sure flags are all updated */
regS = 0xff; /* Stack at back end */
regPC = dGetWordAligned(0xfffc);
}
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