#include "a6502.h" #include #include #define HSYNC 228 #define tick(a) clock += (a); //***********************constructor************************************ m6502::m6502(void) { power_up(); ram = (Byte far *) farmalloc(0x10000L); rom = (Byte far *) farmalloc(0x10000L); for (unsigned i=0;i<65535U;i++) ram[i]=rom[i]=0; } //************************initializer*********************************** void m6502::power_up(void) { pc = 0xfffc; reset_ = 1; //set flags i_ = 1; //disable interrupts //Apparently these flags are undefined for the 6502 at power up //but I will define them anyway. Some program may expect to see //a particular value at power up, so keep this in mind. n=v=b=d=z=c=0; a=x=y=0; s = 0x00; opcode_setup(); //generate an array of function pointers opcode = 0x4c; } //*************************RESET************************************ void m6502::reset(void) { pc = 0xfffc; reset_ = 1; //set flags i_ = 1; //disable interrupts s = 0x00; a=x=y=0; opcode = 0x4c; } void m6502::interrupt_(void) { #ifdef DEBUG puts("interrupt starts"); #endif if (!i_) { ram[SP+ s--] = ((pc-1)>>8)&0xff; ram[SP+ s--] = (pc-1)&0xff; fPHP(); pc = 0xfffe; opcode = 0x4c; } } void m6502::copy_bytes(Word addr, Word num, Byte huge *mem) { for (Word i=0;i 0xffff ) break; } } void m6502::nmi_(void) { ram[SP+ s--] = ((pc-1)>>8)&0xff; ram[SP+ s--] = (pc-1)&0xff; fPHP(); pc = 0xfffa; opcode = 0x4c; } void m6502::print_reg(void) { puts("\n pc a x y s nv_bdizc"); printf("%4x %2x %2x %2x %2x %1x%1x %1x%1x%1x%1x%1x ", unsigned(pc-1),unsigned(a),x,y,s,n,v,b,d,i_,z,c); } void m6502::setup_print(void) { FILE *fin; ch_optab = (char far *) farmalloc(224); optab = (Byte far *) farmalloc(1456); if (optab==NULL || ch_optab==NULL) {puts("out of memory"); exit(0);} fin = fopen("choptab.dat","rb"); for (int i=0;i<56;i++) fscanf(fin, "%s",&ch_optab[i*4]); fclose(fin); fin = fopen("optab.dat","rb"); for (i=0;i<56;i++) fscanf(fin, "%x %x %x %x %x %x %x %x %x %x %x %x %x",&optab[i*13], &optab[i*13+1], &optab[i*13+2],&optab[i*13+3],&optab[i*13+4], &optab[i*13+5], &optab[i*13+6], &optab[i*13+7], &optab[i*13+8], &optab[i*13+9], &optab[i*13+10], &optab[i*13+11], &optab[i*13+12]); fclose(fin); } void m6502::print_opcode(void) { int i,k, row, col; for (i=0;i<56;i++) for (k=0;k<13;k++) if (optab[i*13+k] == opcode) {row = i; col = k;break;} i = row; k = col; Word addr; switch (k) { case 0: printf("%2x %2x %s #$%x", ram[pc-1], ram[pc], &ch_optab[i*4], ram[pc]); break; case 1: addr = Word(ram[pc])+(Word(ram[pc+1])<<8); printf("%2x %2x %2x %s $%x =%2x", ram[pc-1], ram[pc], ram[pc+1], &ch_optab[i*4], addr, ram[addr] ); break; case 2: printf("%2x %2x %s $%x =%2x", ram[pc-1], ram[pc], &ch_optab[i*4], ram[pc], ram[ram[pc]]); break; case 3: printf("%2x %s A", ram[pc-1], &ch_optab[i*4]); break; case 4: printf("%2x %s", ram[pc-1], &ch_optab[i*4]); break; case 5: addr = ram[ram[pc]+x]+(ram[ram[pc]+x+1]<<8); printf("%2x %2x %s ($%x,X) =%2x", ram[pc-1], ram[pc], &ch_optab[i*4], ram[pc], ram[addr]); break; case 6: addr = ram[ram[pc]]+(ram[ram[pc]+1]<<8)+y; printf("%2x %2x %s ($%x),Y =%2x", ram[pc-1], ram[pc], &ch_optab[i*4], ram[pc], ram[addr]); break; case 7: addr = ram[pc]; printf("%2x %2x %s $%x,X =%2x", ram[pc-1], ram[pc], &ch_optab[i*4], addr, ram[addr+x]); break; case 8: addr = Word(ram[pc])+(Word(ram[pc+1])<<8); printf("%2x %2x %2x %s $%x,X =%2x", ram[pc-1], ram[pc], ram[pc+1], &ch_optab[i*4], addr, ram[addr+x]); break; case 9: addr = Word(ram[pc])+(Word(ram[pc+1])<<8); printf("%2x %2x %2x %s $%x,Y =%2x", ram[pc-1], ram[pc], ram[pc+1], &ch_optab[i*4], addr, ram[addr+y]); break; case 10: printf("%2x %2x %s $%x", ram[pc-1], ram[pc], &ch_optab[i*4], int(pc+1)+int((signed char)(ram[pc]))); break; case 11: printf("%2x %2x %2x %s ($%x)", ram[pc-1], ram[pc], ram[pc+1], &ch_optab[i*4], Word(ram[pc])+(Word(ram[pc+1])<<8)); break; case 12: printf("%2x %2x %s $%x,Y =%2x", ram[pc-1], ram[pc], &ch_optab[i*4], ram[pc], ram[ram[pc]+y]); break; default: break; } puts(""); printf ("stack: "); for (i=0xff;i>s;i--) printf("%x ", ram[SP+i]); puts(""); } void m6502::opcode_setup(void) { //OpCodes for 6502 func[0x00] = &m6502::fBRK; func[0x01] = &m6502::fORA_IND_X; func[0x02] = &m6502::fNOP_; func[0x03] = &m6502::fNOP_; func[0x04] = &m6502::fNOP_; func[0x05] = &m6502::fORA_ZP; func[0x06] = &m6502::fASL_ZP; func[0x07] = &m6502::fNOP_; func[0x08] = &m6502::fPHP; func[0x09] = &m6502::fORA_IMM; func[0x0a] = &m6502::fASL_A; func[0x0b] = &m6502::fNOP_; func[0x0c] = &m6502::fNOP_; func[0x0d] = &m6502::fORA_ABS; func[0x0e] = &m6502::fASL_ABS; func[0x0f] = &m6502::fNOP_; func[0x10] = &m6502::fBPL; func[0x11] = &m6502::fORA_IND_Y; func[0x12] = &m6502::fNOP_; func[0x13] = &m6502::fNOP_; func[0x14] = &m6502::fNOP_; func[0x15] = &m6502::fORA_ZP_X; func[0x16] = &m6502::fASL_ZP_X; func[0x17] = &m6502::fNOP_; func[0x18] = &m6502::fCLC_; func[0x19] = &m6502::fORA_ABS_Y; func[0x1A] = &m6502::fNOP_; func[0x1B] = &m6502::fNOP_; func[0x1C] = &m6502::fNOP_; func[0x1D] = &m6502::fORA_ABS_X; func[0x1E] = &m6502::fASL_ABS_X; func[0x1F] = &m6502::fNOP_; func[0x20] = &m6502::fJSR; func[0x21] = &m6502::fAND_IND_X; func[0x22] = &m6502::fNOP_ ; func[0x23] = &m6502::fNOP_; func[0x24] = &m6502::fBIT_ZP; func[0x25] = &m6502::fAND_ZP; func[0x26] = &m6502::fROL_ZP; func[0x27] = &m6502::fNOP_; func[0x28] = &m6502::fPLP; func[0x29] = &m6502::fAND_IMM; func[0x2A] = &m6502::fROL_A; func[0x2B] = &m6502::fNOP_; func[0x2C] = &m6502::fBIT_ABS; func[0x2D] = &m6502::fAND_ABS; func[0x2E] = &m6502::fROL_ABS; func[0x2F] = &m6502::fNOP_; func[0x30] = &m6502::fBMI; func[0x31] = &m6502::fAND_IND_Y; func[0x32] = &m6502::fNOP_; func[0x33] = &m6502::fNOP_; func[0x34] = &m6502::fNOP_; func[0x35] = &m6502::fAND_ZP_X; func[0x36] = &m6502::fROL_ZP_X; func[0x37] = &m6502::fNOP_; func[0x38] = &m6502::fSEC; func[0x39] = &m6502::fAND_ABS_Y; func[0x3A] = &m6502::fNOP_; func[0x3B] = &m6502::fNOP_; func[0x3C] = &m6502::fNOP_; func[0x3D] = &m6502::fAND_ABS_X; func[0x3E] = &m6502::fROL_ABS_X; func[0x3F] = &m6502::fNOP_; func[0x40] = &m6502::fRTI; func[0x41] = &m6502::fEOR_IND_X; func[0x42] = &m6502::fNOP_; func[0x43] = &m6502::fNOP_; func[0x44] = &m6502::fNOP_; func[0x45] = &m6502::fEOR_ZP; func[0x46] = &m6502::fLSR_ZP; func[0x47] = &m6502::fNOP_; func[0x48] = &m6502::fPHA; func[0x49] = &m6502::fEOR_IMM; func[0x4A] = &m6502::fLSR_A; func[0x4B] = &m6502::fNOP_; func[0x4C] = &m6502::fJMP_ABS; func[0x4D] = &m6502::fEOR_ABS; func[0x4E] = &m6502::fLSR_ABS; func[0x4F] = &m6502::fNOP_; func[0x50] = &m6502::fBVC; func[0x51] = &m6502::fEOR_IND_Y; func[0x52] = &m6502::fNOP_; func[0x53] = &m6502::fNOP_; func[0x54] = &m6502::fNOP_; func[0x55] = &m6502::fEOR_ZP_X; func[0x56] = &m6502::fLSR_ZP_X; func[0x57] = &m6502::fNOP_; func[0x58] = &m6502::fCLI_; func[0x59] = &m6502::fEOR_ABS_Y; func[0x5A] = &m6502::fNOP_; func[0x5B] = &m6502::fNOP_; func[0x5C] = &m6502::fNOP_; func[0x5D] = &m6502::fEOR_ABS_X; func[0x5E] = &m6502::fLSR_ABS_X; func[0x5F] = &m6502::fNOP_; func[0x60] = &m6502::fRTS; func[0x61] = &m6502::fADC_IND_X; func[0x62] = &m6502::fNOP_; func[0x63] = &m6502::fNOP_; func[0x64] = &m6502::fNOP_; func[0x65] = &m6502::fADC_ZP; func[0x66] = &m6502::fROR_ZP; func[0x67] = &m6502::fNOP_; func[0x68] = &m6502::fPLA; func[0x69] = &m6502::fADC_IMM; func[0x6A] = &m6502::fROR_A; func[0x6B] = &m6502::fNOP_; func[0x6C] = &m6502::fJMP_IND; func[0x6D] = &m6502::fADC_ABS; func[0x6E] = &m6502::fROR_ABS; func[0x6F] = &m6502::fNOP_; func[0x70] = &m6502::fBVS; func[0x71] = &m6502::fADC_IND_Y; func[0x72] = &m6502::fNOP_; func[0x73] = &m6502::fNOP_; func[0x74] = &m6502::fNOP_; func[0x75] = &m6502::fADC_ZP_X; func[0x76] = &m6502::fROR_ZP_X; func[0x77] = &m6502::fNOP_; func[0x78] = &m6502::fSEI; func[0x79] = &m6502::fADC_ABS_Y; func[0x7A] = &m6502::fNOP_; func[0x7B] = &m6502::fNOP_; func[0x7C] = &m6502::fNOP_; func[0x7D] = &m6502::fADC_ABS_X; func[0x7E] = &m6502::fROR_ABS_X; func[0x7F] = &m6502::fNOP_; func[0x80] = &m6502::fNOP_; func[0x81] = &m6502::fSTA_IND_X; func[0x82] = &m6502::fNOP_; func[0x83] = &m6502::fNOP_; func[0x84] = &m6502::fSTY_ZP; func[0x85] = &m6502::fSTA_ZP; func[0x86] = &m6502::fSTX_ZP; func[0x87] = &m6502::fNOP_; func[0x88] = &m6502::fDEY; func[0x89] = &m6502::fNOP_; func[0x8A] = &m6502::fTXA; func[0x8B] = &m6502::fNOP_; func[0x8C] = &m6502::fSTY_ABS; func[0x8D] = &m6502::fSTA_ABS; func[0x8E] = &m6502::fSTX_ABS; func[0x8F] = &m6502::fNOP_; func[0x90] = &m6502::fBCC; func[0x91] = &m6502::fSTA_IND_Y; func[0x92] = &m6502::fNOP_; func[0x93] = &m6502::fNOP_; func[0x94] = &m6502::fSTY_ZP_X; func[0x95] = &m6502::fSTA_ZP_X; func[0x96] = &m6502::fSTX_ZP_Y; func[0x97] = &m6502::fNOP_; func[0x98] = &m6502::fTYA; func[0x99] = &m6502::fSTA_ABS_Y; func[0x9A] = &m6502::fTXS; func[0x9B] = &m6502::fNOP_; func[0x9C] = &m6502::fNOP_; func[0x9D] = &m6502::fSTA_ABS_X; func[0x9E] = &m6502::fNOP_; func[0x9F] = &m6502::fNOP_; func[0xA0] = &m6502::fLDY_IMM; func[0xA1] = &m6502::fLDA_IND_X; func[0xA2] = &m6502::fLDX_IMM; func[0xA3] = &m6502::fNOP_; func[0xA4] = &m6502::fLDY_ZP; func[0xA5] = &m6502::fLDA_ZP; func[0xA6] = &m6502::fLDX_ZP; func[0xA7] = &m6502::fNOP_; func[0xA8] = &m6502::fTAY; func[0xA9] = &m6502::fLDA_IMM; func[0xAA] = &m6502::fTAX; func[0xAB] = &m6502::fNOP_; func[0xAC] = &m6502::fLDY_ABS; func[0xAD] = &m6502::fLDA_ABS; func[0xAE] = &m6502::fLDX_ABS; func[0xAF] = &m6502::fNOP_; func[0xB0] = &m6502::fBCS; func[0xB1] = &m6502::fLDA_IND_Y; func[0xB2] = &m6502::fNOP_; func[0xB3] = &m6502::fNOP_; func[0xB4] = &m6502::fLDY_ZP_X; func[0xB5] = &m6502::fLDA_ZP_X; func[0xB6] = &m6502::fLDX_ZP_Y; func[0xB7] = &m6502::fNOP_; func[0xB8] = &m6502::fCLV_; func[0xB9] = &m6502::fLDA_ABS_Y; func[0xBA] = &m6502::fTSX; func[0xBB] = &m6502::fNOP_; func[0xBC] = &m6502::fLDY_ABS_X; func[0xBD] = &m6502::fLDA_ABS_X; func[0xBE] = &m6502::fLDX_ABS_Y; func[0xBF] = &m6502::fNOP_; func[0xC0] = &m6502::fCPY_IMM; func[0xC1] = &m6502::fCMP_IND_X; func[0xC2] = &m6502::fNOP_; func[0xC3] = &m6502::fNOP_; func[0xC4] = &m6502::fCPY_ZP; func[0xC5] = &m6502::fCMP_ZP; func[0xC6] = &m6502::fDEC_ZP; func[0xC7] = &m6502::fNOP_; func[0xC8] = &m6502::fINY; func[0xC9] = &m6502::fCMP_IMM; func[0xCA] = &m6502::fDEX; func[0xCB] = &m6502::fNOP_; func[0xCC] = &m6502::fCPY_ABS; func[0xCD] = &m6502::fCMP_ABS; func[0xCE] = &m6502::fDEC_ABS; func[0xCF] = &m6502::fNOP_; func[0xD0] = &m6502::fBNE; func[0xD1] = &m6502::fCMP_IND_Y; func[0xD2] = &m6502::fNOP_; func[0xD3] = &m6502::fNOP_; func[0xD4] = &m6502::fNOP_; func[0xD5] = &m6502::fCMP_ZP_X; func[0xD6] = &m6502::fDEC_ZP_X; func[0xD7] = &m6502::fNOP_; func[0xD8] = &m6502::fCLD_; func[0xD9] = &m6502::fCMP_ABS_Y; func[0xDA] = &m6502::fNOP_; func[0xDB] = &m6502::fNOP_; func[0xDC] = &m6502::fNOP_; func[0xDD] = &m6502::fCMP_ABS_X; func[0xDE] = &m6502::fDEC_ABS_X; func[0xDF] = &m6502::fNOP_; func[0xE0] = &m6502::fCPX_IMM; func[0xE1] = &m6502::fSBC_IND_X; func[0xE2] = &m6502::fNOP_; func[0xE3] = &m6502::fNOP_; func[0xE4] = &m6502::fCPX_ZP; func[0xE5] = &m6502::fSBC_ZP; func[0xE6] = &m6502::fINC_ZP; func[0xE7] = &m6502::fNOP_; func[0xE8] = &m6502::fINX; func[0xE9] = &m6502::fSBC_IMM; func[0xEA] = &m6502::fNOP_; func[0xEB] = &m6502::fNOP_ ; func[0xEC] = &m6502::fCPX_ABS; func[0xED] = &m6502::fSBC_ABS; func[0xEE] = &m6502::fINC_ABS; func[0xEF] = &m6502::fNOP_; func[0xF0] = &m6502::fBEQ; func[0xF1] = &m6502::fSBC_IND_Y; func[0xF2] = &m6502::fNOP_; func[0xF3] = &m6502::fNOP_; func[0xF4] = &m6502::fNOP_; func[0xF5] = &m6502::fSBC_ZP_X; func[0xF6] = &m6502::fINC_ZP_X; func[0xF7] = &m6502::fNOP_; func[0xF8] = &m6502::fSED; func[0xF9] = &m6502::fSBC_ABS_Y; func[0xFA] = &m6502::fNOP_; func[0xFB] = &m6502::fNOP_; func[0xFC] = &m6502::fNOP_; func[0xFD] = &m6502::fSBC_ABS_X; func[0xFE] = &m6502::fINC_ABS_X; func[0xFF] = &m6502::fNOP_; } //OpCodes for 6502 //*************************inline instructions************************* void m6502::fNOP_(void) {tick(2);} //do nothing //*********************direct flag operation*************************** void m6502::fCLC_(void) {c = 0; tick(2);} void m6502::fSEC(void) {c = 1; tick(2);} void m6502::fSEI(void) {i_ = 1; tick(2);} void m6502::fCLI_(void){i_ = 0; tick(2);} void m6502::fSED(void) {d = 1; tick(2);} void m6502::fCLD_(void) {d = 0; tick(2);} void m6502::fCLV_(void) {v = 0; tick(2);} //*****************exchange registers********************************** void m6502::fTSX(void) {x = s;n = (x>>7)&0x01; z = (x==0)?1:0;tick(2);} void m6502::fTAX(void) {x = a;n = (x>>7)&0x01; z = (x==0)?1:0;tick(2);} void m6502::fTAY(void) {y = a;n = (y>>7)&0x01; z = (y==0)?1:0;tick(2);} void m6502::fTXA(void) {a = x;n = (x>>7)&0x01; z = (x==0)?1:0;tick(2);} void m6502::fTYA(void) {a = y;n = (y>>7)&0x01; z = (y==0)?1:0;tick(2);} void m6502::fTXS(void) {s = x;tick(2);} void m6502::fDEX(void) {--x; n = (x>>7)&0x01; z = (x==0)?1:0; tick(2);} void m6502::fDEY(void) {--y; n = (y>>7)&0x01; z = (y==0)?1:0; tick(2);} void m6502::fINY(void) {++y; n = (y>>7)&0x01; z = (y==0)?1:0; tick(2);} void m6502::fINX(void) {++x;n = (x>>7)&0x01; z = (x==0)?1:0; tick(2);} //***************************push and pop******************************** void m6502::fPHP(void) { //I have implement the flags as seperate variables so I must //recombine them here int p = (n<<7)+(v<<6)+(b<<4)+(d<<3)+(i_<<2)+(z<<1)+(c); ram[SP + s--] = p; tick(3); } void m6502::fPLP(void) { int p = Word(ram[SP + ++s]); n = (p>>7)&0x01; v = (p>>6)&0x01; b = (p>>4)&0x01; d = (p>>3)&0x01; i_ = (p>>2)&0x01; z = (p>>1)&0x01; c = p&0x01; tick(4); } void m6502::fPHA(void) {ram[SP + s--] = a;tick(3);} void m6502::fPLA(void) {a = ram[SP + ++s]; z = (a)?1:0; n = (a>>7)&0x01; tick(4);} //********************Program flow chages********************************* //verified 05/18/94 using jsrtest.asm void m6502::fJSR(void) { ram[SP + s--] = ((pc+1)>>8)&0xff; ram[SP + s--] = (pc+1)&0xff; pc = Word(ram[pc])+(Word(ram[pc+1])<<8); tick(6); steal_jsr(pc); } //currently I abort on brk void m6502::fBRK(void) {b = 1; interrupt_();tick(7);} //verified 05/18/94 using jsrtest.asm void m6502::fRTS(void) { pc = Word(ram[SP + ++s]); pc += (Word(ram[SP + ++s])<<8); pc++; tick(6); } void m6502::fRTI(void) { fPLP(); pc = Word(ram[SP + ++s]); pc += (Word(ram[SP + ++s])<<8); tick(6); } //verified 05/18/94 using jsrtest.asm void m6502::fJMP_ABS(void) {pc = Word(ram[pc])+(Word(ram[pc+1])<<8);tick(3);} //verified 05/18/94 using jsrtest.asm void m6502::fJMP_IND(void) {address = Word(ram[pc++]);address += Word(ram[pc])<<8; pc = Word(ram[address])+(Word(ram[address+1])<<8); tick(5);} //brk functions verified using brktest.asm 05/19/94 void m6502::fBVC(void) {if (!v) pc += int((signed char)(ram[pc]));pc++;tick(2);} void m6502::fBVS(void) {if (v) pc += int((signed char)(ram[pc]));pc++;tick(2);} void m6502::fBCC(void){if (!c) pc += int((signed char)(ram[pc]));pc++;tick(2);} void m6502::fBCS(void){if (c) pc += int((signed char)(ram[pc]));pc++;tick(2);} //verified 05/18/94 using jsrtest.asm void m6502::fBNE(void){if (!z) pc += int((signed char)(ram[pc]));pc++;tick(2);} //verified 05/18/94 using jsrtest.asm void m6502::fBEQ(void){if (z) pc += int((signed char)(ram[pc]));pc++;tick(2);} void m6502::fBMI(void){if (n) pc += int((signed char)(ram[pc]));pc++;tick(2);} void m6502::fBPL(void){if (!n) pc += int((signed char)(ram[pc]));pc++;tick(2);} //**********************ORA******************************************* void m6502::fORA_IND_X(void) { address = (Word(ram[pc++])+x)&0xff; //discard carry address = Word(ram[address])+(Word(ram[address+1])<<8); //(ind,x) operand = ram[address]; register int acc = a|operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(6); } void m6502::fORA_ZP(void) { register int acc; address = Word(ram[pc++]); //get zero page address operand = ram[address]; acc = a|operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(3); } void m6502::fORA_IMM(void) { operand = ram[pc++]; //get immediate operand a = a|operand; //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(2); } void m6502::fORA_ABS(void) { register int acc; address = Word(ram[pc++]); address +=(Word(ram[pc++])<<8); operand = ram[address]; acc = a|operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } void m6502::fORA_IND_Y(void) { register int acc; address = Word(ram[pc++]); //get zero page address address = Word(ram[address])+(Word(ram[address+1])<<8)+y; operand = ram[address]; acc = a|operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(5); } void m6502::fORA_ZP_X(void) { register int acc; address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; operand = ram[address]; acc = a|operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } void m6502::fORA_ABS_X(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; operand = ram[address]; acc = a|operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } void m6502::fORA_ABS_Y(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+y; operand = ram[address]; acc = a|operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } //**********************EOR******************************************* void m6502::fEOR_IND_X(void) { register int acc; address = (Word(ram[pc++])+x)&0xff; //discard carry address = Word(ram[address])+(Word(ram[address+1])<<8); //(ind,x) operand = ram[address]; acc = a^operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(6); } void m6502::fEOR_ZP(void) { register int acc; address = Word(ram[pc++]); //get zero page address operand = ram[address]; acc = a^operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(3); } void m6502::fEOR_IMM(void) { operand = ram[pc++]; //get immediate operand a = a^operand; //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(2); } void m6502::fEOR_ABS(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); operand = ram[address]; acc = a^operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } void m6502::fEOR_IND_Y(void) { register int acc; address = Word(ram[pc++]); //get zero page address address = Word(ram[address])+(Word(ram[address+1])<<8)+y; operand = ram[address]; acc = a^operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(5); } void m6502::fEOR_ZP_X(void) { register int acc; address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; operand = ram[address]; acc = a^operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } void m6502::fEOR_ABS_X(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; operand = ram[address]; acc = a^operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } void m6502::fEOR_ABS_Y(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+y; operand = ram[address]; acc = a^operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } //**********************AND******************************************** void m6502::fAND_IND_X(void) { register int acc; address = (Word(ram[pc++])+x)&0xff; //discard carry address = Word(ram[address])+(Word(ram[address+1])<<8); //(ind,x) operand = ram[address]; acc = a&operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(6); } void m6502::fAND_ZP(void) { register int acc; address = Word(ram[pc++]); //get zero page address operand = ram[address]; acc = a&operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(3); } void m6502::fAND_IMM(void) { operand = ram[pc++]; //get immediate operand a = a&operand; //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(2); } void m6502::fAND_ABS(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); operand = ram[address]; acc = a&operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } void m6502::fAND_IND_Y(void) { register int acc; address = Word(ram[pc++]); //get zero page address address = Word(ram[address])+(Word(ram[address+1])<<8)+y; operand = ram[address]; acc = a&operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(5); } void m6502::fAND_ZP_X(void) { register int acc; address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; operand = ram[address]; acc = a&operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } void m6502::fAND_ABS_X(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; operand = ram[address]; acc = a&operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } void m6502::fAND_ABS_Y(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+y; operand = ram[address]; acc = a&operand; a = Byte(acc); //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } //**********************ADC******************************************** void m6502::fADC_IND_X(void) { register int acc, acch, accl; address = (Word(ram[pc++])+x)&0xff; //discard carry address = Word(ram[address])+(Word(ram[address+1])<<8); //(ind,x) operand = ram[address]; if (!d) acc = a+operand+c; else { acc = DEC(a)+DEC(operand)+c; acch = acc%100; accl = acch%10; acc = ((acc>acch)<<8) + ((acch/10)<<4) + accl; a = acc&0xff; } n = (acc>>7)&0x1; Byte a7 = (a>>7)&0x01; Byte o7 = (operand>>7)&0x01; a = Byte(acc); //only effects two flags z = (a==0); c = ((acc&0x100)!=0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(6); } void m6502::fADC_ZP(void) { register int acc, acch, accl; address = Word(ram[pc++]); //get zero page address operand = ram[address]; if (!d) acc = a+operand+c; else { acc = DEC(a)+DEC(operand)+c; acch = acc%100; accl = acch%10; acc = ((acc>acch)<<8) + ((acch/10)<<4) + accl; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = (operand>>7)&0x01; a = Byte(acc); //only effects two flags z = (a==0); c = ((acc&0x100)!=0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(3); } void m6502::fADC_IMM(void) { register int acc, acch, accl; operand = ram[pc++]; //get immediate operand if (!d) acc = a+operand+c; else { acc = DEC(a)+DEC(operand)+c; acch = acc%100; accl = acch%10; acc = ((acc>acch)<<8) + ((acch/10)<<4) + accl; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = (operand>>7)&0x01; a = Byte(acc); //only effects two flags z = (a==0); c = ((acc&0x100)!=0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(2); } void m6502::fADC_ABS(void) { register int acc, acch, accl; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); operand = ram[address]; if (!d) acc = unsigned(a)+unsigned(operand)+unsigned(c); else { acc = DEC(a)+DEC(operand)+c; acch = acc%100; accl = acch%10; acc = ((acc>acch)<<8) + ((acch/10)<<4) + accl; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = (operand>>7)&0x01; a = Byte(acc); //only effects two flags z = (a==0); c = ((acc&0x100)!=0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(4); } void m6502::fADC_IND_Y(void) { register int acc, acch, accl; address = Word(ram[pc++]); //get zero page address address = Word(ram[address])+(Word(ram[address+1])<<8)+y; operand = ram[address]; if (!d) acc = a+operand+c; else { acc = DEC(a)+DEC(operand)+c; acch = acc%100; accl = acch%10; acc = ((acc>acch)<<8) + ((acch/10)<<4) + accl; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = (operand>>7)&0x01; a = Byte(acc); //only effects two flags z = (a==0); c = ((acc&0x100)!=0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(5); } void m6502::fADC_ZP_X(void) { register int acc, acch, accl; address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; operand = ram[address]; if (!d) acc = a+operand+c; else { acc = DEC(a)+DEC(operand)+c; acch = acc%100; accl = acch%10; acc = ((acc>acch)<<8) + ((acch/10)<<4) + accl; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = (operand>>7)&0x01; a = Byte(acc); //only effects two flags z = (a==0); c = ((acc&0x100)!=0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(4); } void m6502::fADC_ABS_X(void) { register int acc, acch, accl; address = Word(ram[pc++]); address += ((Word(ram[pc++])<<8)+x); operand = ram[address]; if (!d) acc = a+operand+c; else { acc = DEC(a)+DEC(operand)+c; acch = acc%100; accl = acch%10; acc = ((acc>acch)<<8) + ((acch/10)<<4) + accl; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = (operand>>7)&0x01; a = Byte(acc); //only effects two flags z = (a==0); c = ((acc&0x100)!=0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(4); } void m6502::fADC_ABS_Y(void) { register int acc, acch, accl; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+y; operand = ram[address]; if (!d) acc = a+operand+c; else { acc = DEC(a)+DEC(operand)+c; acch = acc%100; accl = acch%10; acc = ((acc>acch)<<8) + ((acch/10)<<4) + accl; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = (operand>>7)&0x01; a = Byte(acc); //only effects two flags z = (a==0); c = ((acc&0x100)!=0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(4); } //**********************SBC******************************************** //**STATUS: //** The routines for the flags appear to be correct //********************************************************************* void m6502::fSBC_IND_X(void) { register int acc, acch, accl; address = (Word(ram[pc++])+x)&0xff; //discard carry address = Word(ram[address])+(Word(ram[address+1])<<8); //(ind,x) operand = ram[address]; if (!d) { acc = int(a - operand - !c); if (acc<0) {acc += 0x100; c = 0;} else c = 1; } else { acc = DEC(a) - DEC(operand) - !c; if (acc<0) {acc += 100; c = 0;} else c = 1; acch = acc/100; accl = acc/10; acc = ((acch!=0)*0x100) + (accl<<4) + acc%10; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = !((operand>>7)&0x01); a = Byte(acc); //only effcts three flags z = (a==0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(6); } void m6502::fSBC_ZP(void) { register int acc, acch, accl; address = Word(ram[pc++]); //get zero page address operand = ram[address]; if (!d) { acc = int(a - operand - !c); if (acc<0) {acc += 0x100; c = 0;} else c = 1; } else { acc = DEC(a) - DEC(operand) - !c; if (acc<0) {acc += 100; c = 0;} else c = 1; acch = acc/100; accl = acc/10; acc = ((acch!=0)*0x100) + (accl<<4) + acc%10; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = !((operand>>7)&0x01); a = Byte(acc); //only effects three flags z = (a==0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(3); } void m6502::fSBC_IMM(void) { register int acc, acch, accl; operand = ram[pc++]; //get immediate operand if (!d) { acc = int(a - operand - !c); if (acc<0) {acc += 0x100; c = 0;} else c = 1; } else { acc = DEC(a) - DEC(operand) - !c; if (acc<0) {acc += 100; c = 0;} else c = 1; acch = acc/100; accl = acc/10; acc = ((acch!=0)*0x100) + (accl<<4) + acc%10; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = !((operand>>7)&0x01); a = Byte(acc); //only effects three flags z = (a==0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(2); } void m6502::fSBC_ABS(void) { register int acc, acch, accl; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); operand = ram[address]; if (!d) { acc = int(a - operand - !c); if (acc<0) {acc += 0x100; c = 0;} else c = 1; } else { acc = DEC(a) - DEC(operand) - !c; if (acc<0) {acc += 100; c = 0;} else c = 1; acch = acc/100; accl = acc/10; acc = ((acch!=0)*0x100) + (accl<<4) + acc%10; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = !((operand>>7)&0x01); a = Byte(acc); //only effects three flags z = (a==0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(4); } void m6502::fSBC_IND_Y(void) { register int acc, acch, accl; address = Word(ram[pc++]); //get zero page address address = Word(ram[address])+(Word(ram[address+1])<<8)+y; operand = ram[address]; if (!d) { acc = int(a - operand - !c); if (acc<0) {acc += 0x100; c = 0;} else c = 1; } else { acc = DEC(a) - DEC(operand) - !c; if (acc<0) {acc += 100; c = 0;} else c = 1; acch = acc/100; accl = acc/10; acc = ((acch!=0)*0x100) + (accl<<4) + acc%10; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = !((operand>>7)&0x01); a = Byte(acc); //only effects three flags z = (a==0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(5); } void m6502::fSBC_ZP_X(void) { register int acc, acch, accl; address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; operand = ram[address]; if (!d) { acc = int(a - operand - !c); if (acc<0) {acc += 0x100; c = 0;} else c = 1; } else { acc = DEC(a) - DEC(operand) - !c; if (acc<0) {acc += 100; c = 0;} else c = 1; acch = acc/100; accl = acc/10; acc = ((acch!=0)*0x100) + (accl<<4) + acc%10; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = !((operand>>7)&0x01); a = Byte(acc); //only effects three flags z = (a==0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(4); } void m6502::fSBC_ABS_X(void) { register int acc, acch, accl; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; operand = ram[address]; if (!d) { acc = int(a - operand - !c); if (acc<0) {acc += 0x100; c = 0;} else c = 1; } else { acc = DEC(a) - DEC(operand) - !c; if (acc<0) {acc += 100; c = 0;} else c = 1; acch = acc/100; accl = acc/10; acc = ((acch!=0)*0x100) + (accl<<4) + acc%10; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = !((operand>>7)&0x01); a = Byte(acc); //only effects three flags z = (a==0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(4); } void m6502::fSBC_ABS_Y(void) { register int acc, acch, accl; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+y; operand = ram[address]; if (!d) { acc = int(a - operand - !c); if (acc<0) {acc += 0x100; c = 0;} else c = 1; } else { acc = DEC(a) - DEC(operand) - !c; if (acc<0) {acc += 100; c = 0;} else c = 1; acch = acc/100; accl = acc/10; acc = ((acch!=0)*0x100) + (accl<<4) + acc%10; a = acc&0xff; } n = (acc>>7)&0x01; Byte a7 = (a>>7)&0x01; Byte o7 = !((operand>>7)&0x01); a = Byte(acc); //only effects three flags z = (a==0); v = (a7 & o7 & (!n)) || ((!a7) & (!o7) & n); tick(4); } //**********************CMP******************************************** void m6502::fCMP_IND_X(void) { register int acc, acch, accl; address = (Word(ram[pc++])+x)&0xff; //discard carry address = Word(ram[address])+(Word(ram[address+1])<<8); //(ind,x) operand = ram[address]; acc = int(a-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(6); } void m6502::fCMP_ZP(void) { register int acc, acch, accl; address = Word(ram[pc++]); //get zero page address operand = ram[address]; acc = int(a-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(3); } void m6502::fCMP_IMM(void) { register int acc, acch, accl; operand = ram[pc++]; //get immediate operand acc = int(a-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(2); } void m6502::fCMP_ABS(void) { register int acc, acch, accl; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); operand = ram[address]; acc = int(a-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(4); } void m6502::fCMP_IND_Y(void) { register int acc, acch, accl; address = Word(ram[pc++]); //get zero page address address = Word(ram[address])+(Word(ram[address+1])<<8)+y; operand = ram[address]; acc = int(a-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(5); } void m6502::fCMP_ZP_X(void) { register int acc, acch, accl; address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; operand = ram[address]; acc = int(a-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(4); } void m6502::fCMP_ABS_X(void) { register int acc, acch, accl; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; operand = ram[address]; acc = int(a-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(4); } void m6502::fCMP_ABS_Y(void) { register int acc, acch, accl; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+y; operand = ram[address]; acc = int(a-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(4); } void m6502::fCPY_ABS(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); operand = ram[address]; register int acc;; acc = int(y-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; z = ((acc&0xff)==0); n = (a>>7)&0x01; tick(4); } void m6502::fCPY_ZP(void) { operand = ram[Word(ram[pc++])]; register int acc;; acc = int(y-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; z = ((acc&0xff)==0); n = (a>>7)&0x01; tick(3); } void m6502::fCPY_IMM(void) { operand = ram[pc++]; register int acc;; acc = int(y-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; z = ((acc&0xff)==0); n = (a>>7)&0x01; tick(2); } void m6502::fCPX_ABS(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); operand = ram[address]; register int acc;; acc = int(x-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; z = ((acc&0xff)==0); n = (a>>7)&0x01; tick(4); } void m6502::fCPX_ZP(void) { operand = ram[Word(ram[pc++])]; register int acc;; acc = int(x-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; z = ((acc&0xff)==0); n = (a>>7)&0x01; tick(3); } void m6502::fCPX_IMM(void) { operand = ram[pc++]; register int acc;; acc = int(x-operand); if (acc<0) {acc += 0x100; c = 0;} else c = 1; z = ((acc&0xff)==0); n = (a>>7)&0x01; tick(2); } //************************ASL***************************************** void m6502::fASL_ZP(void) { register int acc; address = Word(ram[pc++]); //get zero page address operand = ram[address]; acc = operand<<1; write_ram( Byte(acc)); //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; c = ((acc&0x100)!=0); tick(5); } void m6502::fASL_A(void) { register int acc; acc = a<<1; a = Byte(acc); //effects three flags z = (a==0); n = (a>>7)&0x01; c = ((acc&0x100)!=0); tick(2); } void m6502::fASL_ABS(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); operand = ram[address]; acc = operand<<1; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; c = ((acc&0x100)!=0); tick(6); } void m6502::fASL_ZP_X(void) { register int acc; address = Word(ram[pc++])+x; operand = ram[address]; acc = operand<<1; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; c = ((acc&0x100)!=0); tick(6); } void m6502::fASL_ABS_X(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; operand = ram[address]; acc = operand<<1; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; c = ((acc&0x100)!=0); tick(7); } //************************LSR***************************************** void m6502::fLSR_ZP(void) { register int acc; address = Word(ram[pc++]); //get zero page address operand = ram[address]; acc = operand>>1; c = operand&0x1; write_ram( Byte(acc)); //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(5); } void m6502::fLSR_A(void) { register int acc; c = a&0x1; acc = a>>1; a = Byte(acc); //effects three flags z = (a==0); n = (a>>7)&0x01; tick(2); } void m6502::fLSR_ABS(void) { register int acc; address = Word(ram[pc++])+(Word(ram[pc++])<<8); operand = ram[address]; acc = operand>>1; c = operand&0x1; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(6); } void m6502::fLSR_ZP_X(void) { register int acc; address = Word(ram[pc++])+x; operand = ram[address]; acc = operand>>1; c = operand&0x1; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(6); } void m6502::fLSR_ABS_X(void) { register int acc; address = Word(ram[pc++])+(Word(ram[pc++])<<8)+x; operand = ram[address]; acc = operand>>1; c = operand&0x1; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(7); } //************************ROL***************************************** void m6502::fROL_ZP(void) { register int acc; address = Word(ram[pc++]); //get zero page address operand = ram[address]; acc = (operand<<1)|c; write_ram( Byte(acc)); //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; c = ((acc&0x100)!=0); tick(5); } void m6502::fROL_A(void) { register int acc; acc = (a<<1)|c; a = Byte(acc); //effects three flags z = (a==0); n = (a>>7)&0x01; c = ((acc&0x100)!=0); tick(2); } void m6502::fROL_ABS(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); operand = ram[address]; acc = (operand<<1)|c; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; c = ((acc&0x100)!=0); tick(6); } void m6502::fROL_ZP_X(void) { register int acc; address = Word(ram[pc++])+x; operand = ram[address]; acc = (operand<<1)|c; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; c = ((acc&0x100)!=0); tick(6); } void m6502::fROL_ABS_X(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; operand = ram[address]; acc = (operand<<1)|c; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; c = ((acc&0x100)!=0); tick(7); } //************************ROR***************************************** void m6502::fROR_ZP(void) { register int acc; address = Word(ram[pc++]); //get zero page address operand = ram[address]; acc = (operand>>1)|(c<<7); c = operand&0x1; write_ram( Byte(acc)); //only effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(5); } void m6502::fROR_A(void) { register int acc; acc = (a>>1)|(c<<7); c = a&0x1; a = Byte(acc); //effects three flags z = (a==0); n = (a>>7)&0x01; c = ((acc&0x100)!=0); tick(2); } void m6502::fROR_ABS(void) { register int acc; address = Word(ram[pc++])+(Word(ram[pc++])<<8); operand = ram[address]; acc = (operand>>1)|(c<<7); c = operand&0x1; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(6); } void m6502::fROR_ZP_X(void) { register int acc; address = Word(ram[pc++])+x; operand = ram[address]; acc = (operand>>1)|(c<<7); c = operand&0x1; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(6); } void m6502::fROR_ABS_X(void) { register int acc; address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; operand = ram[address]; acc = (operand>>1)|(c<<7); c = operand&0x1; write_ram( Byte(acc)); //effects three flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(7); } void m6502::fBIT_ZP(void) { operand = ram[pc++]; z = ((a&operand)==0); n = ((operand&b7)!=0); v = ((operand&b6)!=0); tick(2); } void m6502::fBIT_ABS(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); operand = ram[address]; z = ((a&operand)==0); n = ((operand&b7)!=0); v = ((operand&b6)!=0); tick(4); } //**********************STA******************************************** void m6502::fSTA_IND_X(void) { address = (Word(ram[pc++])+x)&0xff; //discard carry address = Word(ram[address])+(Word(ram[address+1])<<8); //(ind,x) write_ram(); //ram[address] = a tick(6); } void m6502::fSTA_ZP(void) { address = Word(ram[pc++]); //get zero page address write_ram(); //ram[address] = a tick(3); } void m6502::fSTA_ABS(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); write_ram(); //ram[address] = a tick(4); } void m6502::fSTA_IND_Y(void) { address = Word(ram[pc++]); //get zero page address address = Word(ram[address])+(Word(ram[address+1])<<8)+y; write_ram(); //ram[address] = a tick(6); } void m6502::fSTA_ZP_X(void) { address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; write_ram(); //ram[address] = a tick(4); } void m6502::fSTA_ABS_X(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; write_ram(); //ram[address] = a tick(5); } void m6502::fSTA_ABS_Y(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+y; write_ram(); //ram[address] = a tick(5); } //**********************LDA******************************************* void m6502::fLDA_IND_X(void) { address = (Word(ram[pc++])+x)&0xff; //discard carry address = Word(ram[address])+(Word(ram[address+1])<<8); //(ind,x) a = ram[address]; //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(6); } void m6502::fLDA_ZP(void) { address = Word(ram[pc++]); //get zero page address a = ram[address]; //effects two flags z = (a==0); n = (a>>7)&0x01; tick(3); } void m6502::fLDA_IMM(void) { a = Word(ram[pc++]); //get immediate operand //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(2); } void m6502::fLDA_ABS(void) { address = Word(ram[pc++]); address +=(Word(ram[pc++])<<8); a = ram[address]; //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } void m6502::fLDA_IND_Y(void) { address = Word(ram[pc++]); //get zero page address address = Word(ram[address])+(Word(ram[address+1])<<8)+y; a = ram[address]; //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(6); } void m6502::fLDA_ZP_X(void) { address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; a = ram[address]; //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(4); } void m6502::fLDA_ABS_X(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; a = ram[address]; //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(5); } void m6502::fLDA_ABS_Y(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+y; a = ram[address]; //only effects two flags z = (a==0); n = (a>>7)&0x01; tick(5); } //**********************STY******************************************** void m6502::fSTY_ZP(void) { address = Word(ram[pc++]); //get zero page address write_ram(y); //ram[address] = a tick(4); } void m6502::fSTY_ABS(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); write_ram(y); //ram[address] = a tick(4); } void m6502::fSTY_ZP_X(void) { address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; write_ram(y); //ram[address] = a tick(3); } //**********************STX******************************************** void m6502::fSTX_ZP(void) { address = Word(ram[pc++]); //get zero page address write_ram(x); //ram[address] = a tick(4); } void m6502::fSTX_ZP_Y(void) { address = (Word(ram[pc++])+y)&0xffff; write_ram(x); //ram[address] = a tick(4); } void m6502::fSTX_ABS(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8); write_ram(x); //ram[address] = a tick(3); } //**********************LDY******************************************* void m6502::fLDY_ZP(void) { address = Word(ram[pc++]); //get zero page address y = ram[address]; //effects two flags z = (y==0); n = (y>>7)&0x01; tick(3); } void m6502::fLDY_IMM(void) { y = Word(ram[pc++]); //get immediate operand //only effects two flags z = (y==0); n = (y>>7)&0x01; tick(2); } void m6502::fLDY_ABS(void) { address = Word(ram[pc++]); address +=(Word(ram[pc++])<<8); y = ram[address]; //only effects two flags z = (y==0); n = (y>>7)&0x01; tick(4); } void m6502::fLDY_ZP_X(void) { address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; y = ram[address]; //only effects two flags z = (y==0); n = (y>>7)&0x01; tick(3); } void m6502::fLDY_ABS_X(void) { address = Word(ram[pc++]); address +=(Word(ram[pc++])<<8); y = ram[address+x]; //only effects two flags z = (y==0); n = (y>>7)&0x01; tick(4); } //**********************LDX******************************************* void m6502::fLDX_ZP(void) { address = Word(ram[pc++]); //get zero page address x = ram[address]; //effects two flags z = (x==0); n = (x>>7)&0x01; tick(3); } void m6502::fLDX_IMM(void) { x = Word(ram[pc++]); //get immediate operand //only effects two flags z = (x==0); n = (x>>7)&0x01; tick(2); } void m6502::fLDX_ABS(void) { address = Word(ram[pc++]); address +=(Word(ram[pc++])<<8); x = ram[address]; //only effects two flags z = (x==0); n = (x>>7)&0x01; tick(4); } void m6502::fLDX_ABS_Y(void) { address = Word(ram[pc++]); address +=(Word(ram[pc++])<<8); x = ram[address+y]; //only effects two flags z = (x==0); n = (x>>7)&0x01; tick(3); } void m6502::fLDX_ZP_Y(void) { address = Word(ram[pc++]); //get zero page address address = (address+y)&0xff; x = ram[address]; //only effects two flags z = (x==0); n = (x>>7)&0x01; tick(4); } //**********************DEC******************************************* void m6502::fDEC_ZP(void) { address = Word(ram[pc++]); //get zero page address register int acc = (ram[address])-1; write_ram(address,acc); //effects two flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(5); } void m6502::fDEC_ABS(void) { address = Word(ram[pc++]); address +=(Word(ram[pc++])<<8); register int acc = (ram[address])-1; write_ram(address,acc); //only effects two flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(6); } void m6502::fDEC_ZP_X(void) { address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; register int acc = (ram[address])-1; write_ram(address,acc); //only effects two flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(6); } void m6502::fDEC_ABS_X(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; register int acc = (ram[address])-1; write_ram(address,acc); //only effects two flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(7); } //**********************INC******************************************* void m6502::fINC_ZP(void) { address = Word(ram[pc++]); //get zero page address register int acc = (ram[address])+1; write_ram(address,acc); //effects two flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(5); } void m6502::fINC_ABS(void) { address = Word(ram[pc++]); address +=(Word(ram[pc++])<<8); register int acc = (ram[address])+1; write_ram(address,acc); //only effects two flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(6); } void m6502::fINC_ZP_X(void) { address = Word(ram[pc++]); //get zero page address address = (address+x)&0xff; register int acc = (ram[address])+1; write_ram(address,acc); //only effects two flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(6); } void m6502::fINC_ABS_X(void) { address = Word(ram[pc++]); address += (Word(ram[pc++])<<8)+x; register int acc = (ram[address])+1; write_ram(address,acc); //only effects two flags z = ((acc&0xff)==0); n = (acc>>7)&0x01; tick(7); }