Added 65c02 Instructions NEEDS TESTING!
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203
src/cpu.c
203
src/cpu.c
@ -1,7 +1,7 @@
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/* Fake6502 CPU emulator core v1.1 *******************
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* (c)2011-2013 Mike Chambers *
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* *
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* Modified by Gabriel Weingardt *
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* Modified for 65c02 by Gabriel Weingardt *
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*****************************************************/
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#include <stdint.h>
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@ -130,6 +130,10 @@ static void zp() { //zero-page
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ea = (uint16_t)read6502((uint16_t)pc++);
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}
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static void izp() { // zero-page indirect (new 65c02 instruction)
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}
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static void zpx() { //zero-page,X
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ea = ((uint16_t)read6502((uint16_t)pc++) + (uint16_t)x) & 0xFF; //zero-page wraparound
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}
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@ -201,6 +205,16 @@ static void indy() { // (indirect),Y
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}
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}
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// new 65c02 address mode
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static void aii() { // absolute indexed indirect
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uint16_t eahelp, eahelp2;
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eahelp = ((uint16_t)read6502(pc) | ((uint16_t)read6502(pc+1) << 8)) + x;
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eahelp2 = (eahelp & 0xFF00) | ((eahelp + 1) & 0x00FF); //replicate 6502 page-boundary wraparound bug
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ea = (uint16_t)read6502(eahelp) | ((uint16_t)read6502(eahelp2) << 8);
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pc += 2;
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}
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static uint16_t getvalue() {
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if (addrtable[opcode] == acc) return((uint16_t)a);
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else return((uint16_t)read6502(ea));
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@ -336,6 +350,37 @@ static void bvs() {
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}
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}
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static void bra() { // new 65c02 instruction
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oldpc = pc;
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pc += reladdr;
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if ((oldpc & 0xFF00) != (pc & 0xFF00)) clockticks6502 += 2; //check if jump crossed a page boundary
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else clockticks6502++;
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}
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static void bbr() { // new 65c02 instruction
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uint8_t testval = 1;
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for (int i = 0; i < ((opcode & 0b01110000) >> 4); i++) testval = testval << 1;
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if (!(a & testval)) {
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oldpc = pc;
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pc += reladdr;
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if ((oldpc & 0xFF00) != (pc & 0xFF00)) clockticks6502 += 2; //check if jump crossed a page boundary
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else clockticks6502++;
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}
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}
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static void bbs() { // new 65c02 instruction
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uint8_t testval = 1;
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for (int i = 0; i < ((opcode & 0b01110000) >> 4); i++) testval = testval << 1;
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if (a & testval) {
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oldpc = pc;
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pc += reladdr;
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if ((oldpc & 0xFF00) != (pc & 0xFF00)) clockticks6502 += 2; //check if jump crossed a page boundary
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else clockticks6502++;
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}
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}
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static void clc() {
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clearcarry();
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}
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@ -522,9 +567,18 @@ static void pha() {
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}
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static void php() {
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push8(status | FLAG_BREAK);
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push8(status);
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}
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static void phy() { // new 65c02 instruction
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push8(y);
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}
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static void phx() { // new 65c02 instruction
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push8(x);
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}
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static void pla() {
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a = pull8();
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@ -536,6 +590,21 @@ static void plp() {
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status = pull8() | FLAG_CONSTANT;
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}
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static void ply() { // new 65c02 instruction
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y = pull8();
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zerocalc(y);
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signcalc(y);
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}
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static void plx() { // new 65c02 instruction
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a = pull8();
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zerocalc(x);
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signcalc(x);
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}
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static void rol() {
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value = getvalue();
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result = (value << 1) | (status & FLAG_CARRY);
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@ -608,6 +677,10 @@ static void sty() {
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putvalue(y);
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}
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static void stz() { // new 65c02 instruction
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putvalue(0);
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}
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static void tax() {
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x = a;
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@ -647,44 +720,88 @@ static void tya() {
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signcalc(a);
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}
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static void (*addrtable[256])() = {
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/* | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F | */
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/* 0 */ imp, indx, imp, indx, zp, zp, zp, zp, imp, imm, acc, imm, abso, abso, abso, abso, /* 0 */
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/* 1 */ rel, indy, imp, indy, zpx, zpx, zpx, zpx, imp, absy, imp, absy, absx, absx, absx, absx, /* 1 */
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/* 2 */ abso, indx, imp, indx, zp, zp, zp, zp, imp, imm, acc, imm, abso, abso, abso, abso, /* 2 */
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/* 3 */ rel, indy, imp, indy, zpx, zpx, zpx, zpx, imp, absy, imp, absy, absx, absx, absx, absx, /* 3 */
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/* 4 */ imp, indx, imp, indx, zp, zp, zp, zp, imp, imm, acc, imm, abso, abso, abso, abso, /* 4 */
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/* 5 */ rel, indy, imp, indy, zpx, zpx, zpx, zpx, imp, absy, imp, absy, absx, absx, absx, absx, /* 5 */
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/* 6 */ imp, indx, imp, indx, zp, zp, zp, zp, imp, imm, acc, imm, ind, abso, abso, abso, /* 6 */
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/* 7 */ rel, indy, imp, indy, zpx, zpx, zpx, zpx, imp, absy, imp, absy, absx, absx, absx, absx, /* 7 */
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/* 8 */ imm, indx, imm, indx, zp, zp, zp, zp, imp, imm, imp, imm, abso, abso, abso, abso, /* 8 */
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/* 9 */ rel, indy, imp, indy, zpx, zpx, zpy, zpy, imp, absy, imp, absy, absx, absx, absy, absy, /* 9 */
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/* A */ imm, indx, imm, indx, zp, zp, zp, zp, imp, imm, imp, imm, abso, abso, abso, abso, /* A */
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/* B */ rel, indy, imp, indy, zpx, zpx, zpy, zpy, imp, absy, imp, absy, absx, absx, absy, absy, /* B */
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/* C */ imm, indx, imm, indx, zp, zp, zp, zp, imp, imm, imp, imm, abso, abso, abso, abso, /* C */
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/* D */ rel, indy, imp, indy, zpx, zpx, zpx, zpx, imp, absy, imp, absy, absx, absx, absx, absx, /* D */
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/* E */ imm, indx, imm, indx, zp, zp, zp, zp, imp, imm, imp, imm, abso, abso, abso, abso, /* E */
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/* F */ rel, indy, imp, indy, zpx, zpx, zpx, zpx, imp, absy, imp, absy, absx, absx, absx, absx /* F */
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};
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static void trb() { // new 65c02 instruction
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value = getvalue();
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result = value & ~a;
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zerocalc(result);
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putvalue(result);
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}
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static void tsb() { // new 65c02 instruction
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value = getvalue();
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result = value | a;
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zerocalc(result);
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putvalue(result);
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}
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static void rmb() { // new 65c02 instruction
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uint8_t testval = 1;
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for (int i = 0; i < ((opcode & 0b01110000) >> 4); i++) testval = testval << 1;
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value = getvalue();
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result = value & ~testval;
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putvalue(result);
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}
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static void smb() { // new 65c02 instruction
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uint8_t testval = 1;
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for (int i = 0; i < ((opcode & 0b01110000) >> 4); i++) testval = testval << 1;
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value = getvalue();
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result = value | testval;
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putvalue(result);
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}
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static void wai() { // new 65c02 instruction
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// implement later
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}
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static void stp() { // new 65c02 instruction
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// implement later
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}
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static void (*optable[256])() = {
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/* | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F | */
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/* 0 */ brk, ora, nop, nop, nop, ora, asl, nop, php, ora, asl, nop, nop, ora, asl, nop, /* 0 */
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/* 1 */ bpl, ora, nop, nop, nop, ora, asl, nop, clc, ora, nop, nop, nop, ora, asl, nop, /* 1 */
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/* 2 */ jsr, and, nop, nop, bit, and, rol, nop, plp, and, rol, nop, bit, and, rol, nop, /* 2 */
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/* 3 */ bmi, and, nop, nop, nop, and, rol, nop, sec, and, nop, nop, nop, and, rol, nop, /* 3 */
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/* 4 */ rti, eor, nop, nop, nop, eor, lsr, nop, pha, eor, lsr, nop, jmp, eor, lsr, nop, /* 4 */
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/* 5 */ bvc, eor, nop, nop, nop, eor, lsr, nop, cli, eor, nop, nop, nop, eor, lsr, nop, /* 5 */
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/* 6 */ rts, adc, nop, nop, nop, adc, ror, nop, pla, adc, ror, nop, jmp, adc, ror, nop, /* 6 */
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/* 7 */ bvs, adc, nop, nop, nop, adc, ror, nop, sei, adc, nop, nop, nop, adc, ror, nop, /* 7 */
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/* 8 */ nop, sta, nop, nop, sty, sta, stx, nop, dey, nop, txa, nop, sty, sta, stx, nop, /* 8 */
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/* 9 */ bcc, sta, nop, nop, sty, sta, stx, nop, tya, sta, txs, nop, nop, sta, nop, nop, /* 9 */
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/* A */ ldy, lda, ldx, nop, ldy, lda, ldx, nop, tay, lda, tax, nop, ldy, lda, ldx, nop, /* A */
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/* B */ bcs, lda, nop, nop, ldy, lda, ldx, nop, clv, lda, tsx, nop, ldy, lda, ldx, nop, /* B */
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/* C */ cpy, cmp, nop, nop, cpy, cmp, dec, nop, iny, cmp, dex, nop, cpy, cmp, dec, nop, /* C */
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/* D */ bne, cmp, nop, nop, nop, cmp, dec, nop, cld, cmp, nop, nop, nop, cmp, dec, nop, /* D */
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/* E */ cpx, sbc, nop, nop, cpx, sbc, inc, nop, inx, sbc, nop, sbc, cpx, sbc, inc, nop, /* E */
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/* F */ beq, sbc, nop, nop, nop, sbc, inc, nop, sed, sbc, nop, nop, nop, sbc, inc, nop /* F */
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/* 0 */ brk, ora, nop, nop, tsb, ora, asl, rmb, php, ora, asl, nop, tsb, ora, asl, bbr, /* 0 */
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/* 1 */ bpl, ora, ora, nop, trb, ora, asl, rmb, clc, ora, inc, nop, trb, ora, asl, bbr, /* 1 */
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/* 2 */ jsr, and, nop, nop, bit, and, rol, rmb, plp, and, rol, nop, bit, and, rol, bbr, /* 2 */
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/* 3 */ bmi, and, and, nop, bit, and, rol, rmb, sec, and, dec, nop, bit, and, rol, bbr, /* 3 */
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/* 4 */ rti, eor, nop, nop, nop, eor, lsr, rmb, pha, eor, lsr, nop, jmp, eor, lsr, bbr, /* 4 */
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/* 5 */ bvc, eor, eor, nop, nop, eor, lsr, rmb, cli, eor, phy, nop, nop, eor, lsr, bbr, /* 5 */
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/* 6 */ rts, adc, nop, nop, stz, adc, ror, rmb, pla, adc, ror, nop, jmp, adc, ror, bbr, /* 6 */
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/* 7 */ bvs, adc, adc, nop, stz, adc, ror, rmb, sei, adc, ply, nop, jmp, adc, ror, bbr, /* 7 */
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/* 8 */ bra, sta, nop, nop, sty, sta, stx, smb, dey, bit, txa, nop, sty, sta, stx, bbs, /* 8 */
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/* 9 */ bcc, sta, sta, nop, sty, sta, stx, smb, tya, sta, txs, nop, stz, sta, stz, bbs, /* 9 */
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/* A */ ldy, lda, ldx, nop, ldy, lda, ldx, smb, tay, lda, tax, nop, ldy, lda, ldx, bbs, /* A */
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/* B */ bcs, lda, lda, nop, ldy, lda, ldx, smb, clv, lda, tsx, nop, ldy, lda, ldx, bbs, /* B */
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/* C */ cpy, cmp, nop, nop, cpy, cmp, dec, smb, iny, cmp, dex, wai, cpy, cmp, dec, bbs, /* C */
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/* D */ bne, cmp, cmp, nop, nop, cmp, dec, smb, cld, cmp, phx, stp, nop, cmp, dec, bbs, /* D */
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/* E */ cpx, sbc, nop, nop, cpx, sbc, inc, smb, inx, sbc, nop, sbc, cpx, sbc, inc, bbs, /* E */
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/* F */ beq, sbc, sbc, nop, nop, sbc, inc, smb, sed, sbc, plx, nop, nop, sbc, inc, bbs /* F */
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};
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static void (*addrtable[256])() = {
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/* | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F | */
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/* 0 */ imp, indx, imp, indx, zp, zp, zp, zp, imp, imm, acc, imm, abso, abso, abso, rel, /* 0 */
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/* 1 */ rel, indy, izp, indy, zp, zpx, zpx, zp, imp, absy, acc, absy, abso, absx, absx, rel, /* 1 */
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/* 2 */ abso, indx, imp, indx, zp, zp, zp, zp, imp, imm, acc, imm, abso, abso, abso, rel, /* 2 */
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/* 3 */ rel, indy, izp, indy, zpx, zpx, zpx, zp, imp, absy, acc, absy, absx, absx, absx, rel, /* 3 */
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/* 4 */ imp, indx, imp, indx, zp, zp, zp, zp, imp, imm, acc, imm, abso, abso, abso, rel, /* 4 */
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/* 5 */ rel, indy, izp, indy, zpx, zpx, zpx, zp, imp, absy, imp, absy, absx, absx, absx, rel, /* 5 */
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/* 6 */ imp, indx, imp, indx, zp, zp, zp, zp, imp, imm, acc, imm, ind, abso, abso, rel, /* 6 */
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/* 7 */ rel, indy, izp, indy, zpx, zpx, zpx, zp, imp, absy, imp, absy, aii, absx, absx, rel, /* 7 */
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/* 8 */ rel, indx, imm, indx, zp, zp, zp, zp, imp, imm, imp, imm, abso, abso, abso, rel, /* 8 */
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/* 9 */ rel, indy, izp, indy, zpx, zpx, zpy, zp, imp, absy, imp, absy, abso, absx, absx, rel, /* 9 */
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/* A */ imm, indx, imm, indx, zp, zp, zp, zp, imp, imm, imp, imm, abso, abso, abso, rel, /* A */
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/* B */ rel, indy, izp, indy, zpx, zpx, zpy, zp, imp, absy, imp, absy, absx, absx, absy, rel, /* B */
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/* C */ imm, indx, imm, indx, zp, zp, zp, zp, imp, imm, imp, imp, abso, abso, abso, rel, /* C */
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/* D */ rel, indy, izp, indy, zpx, zpx, zpx, zp, imp, absy, imp, imp, absx, absx, absx, rel, /* D */
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/* E */ imm, indx, imm, indx, zp, zp, zp, zp, imp, imm, imp, imm, abso, abso, abso, rel, /* E */
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/* F */ rel, indy, izp, indy, zpx, zpx, zpx, zp, imp, absy, imp, absy, absx, absx, absx, rel /* F */
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};
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static const uint32_t ticktable[256] = {
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@ -716,10 +833,14 @@ void nmi6502() {
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}
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void irq6502() {
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push16(pc);
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push8(status);
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status |= FLAG_INTERRUPT;
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pc = (uint16_t)read6502(0xFFFE) | ((uint16_t)read6502(0xFFFF) << 8);
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// only initiate interrupts when interrupt flag is cleared
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if (!(status & FLAG_INTERRUPT)){
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push16(pc);
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push8(status);
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status |= FLAG_INTERRUPT;
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pc = (uint16_t)read6502(0xFFFE) | ((uint16_t)read6502(0xFFFF) << 8);
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}
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}
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void step6502() {
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