6502 emulator for Commodore 64 ROMs, serial terminal edition for MBED. Recommend terminal echo on, line edit on, caps lock, 115200bps, implicit carriage return on newline, currently non-buffered so don't paste lots of stuff
More details at:
[https://github.com/davervw] [https://techwithdave.davevw.com/2020/03/simple-emu-c64.html]
emu6502.cpp
- Committer:
- davervw
- Date:
- 2020-04-12
- Revision:
- 4:0461c100cbbb
- Parent:
- 0:90de1cbc8a5f
- Child:
- 7:f49fa56672d8
File content as of revision 4:0461c100cbbb:
// emu6502.c - Emu6502 - MOS6502 Emulator // //////////////////////////////////////////////////////////////////////////////// // // c-simple-emu-cbm (C Portable Version) // C64/6502 Emulator for Microsoft Windows Console // // MIT License // // Copyright(c) 2020 by David R.Van Wagner // davevw.com // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in all // copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE // SOFTWARE. // //////////////////////////////////////////////////////////////////////////////// //#define snprintf sprintf_s #include <mbed.h> #include "emu6502.h" // global references extern Serial pc; // globals byte A = 0; byte X = 0; byte Y = 0; byte S = 0xFF; bool N = false; bool V = false; bool B = false; bool D = false; bool I = false; bool Z = false; bool C = false; ushort PC = 0; bool trace = false; bool step = false; #define USE_IRQ 0 extern void ResetRun(bool (*ExecutePatch)(void)) { ushort addr = (ushort)((GetMemory(0xFFFC) | (GetMemory(0xFFFD) << 8))); // RESET vector Execute(addr, ExecutePatch); } #ifndef WIN32 static void strcpy_s(char* dest, size_t size, const char* src) { strncpy(dest, src, size); } static void strcat_s(char* dest, size_t size, const char* src) { strncat(dest, src, size); } #endif static void PHP() { int flags = (N ? 0x80 : 0) | (V ? 0x40 : 0) | (B ? 0x10 : 0) | (D ? 0x08 : 0) | (I ? 0x04 : 0) | (Z ? 0x02 : 0) | (C ? 0x01 : 0); Push(flags); } extern byte LO(ushort value) { return (byte)value; } extern byte HI(ushort value) { return (byte)(value >> 8); } static void BRK(byte *p_bytes) { ++PC; Push(HI(PC)); Push(LO(PC)); PHP(); B = true; PC = (ushort)(GetMemory(0xFFFE) + (GetMemory(0xFFFF) << 8)); *p_bytes = 0; } static byte Subtract(byte reg, byte value, bool *p_overflow) { bool old_reg_neg = (reg & 0x80) != 0; bool value_neg = (value & 0x80) != 0; int result = reg - value - (C ? 0 : 1); N = (result & 0x80) != 0; C = (result >= 0); Z = (result == 0); bool result_neg = (result & 0x80) != 0; *p_overflow = (old_reg_neg && !value_neg && !result_neg) // neg - pos = pos || (!old_reg_neg && value_neg && result_neg); // pos - neg = neg return (byte)result; } static byte SubtractWithoutOverflow(byte reg, byte value) { C = true; // init for CMP, etc. bool unused; return Subtract(reg, value, &unused); } static void CMP(byte value) { SubtractWithoutOverflow(A, value); } static void CPX(byte value) { SubtractWithoutOverflow(X, value); } static void CPY(byte value) { SubtractWithoutOverflow(Y, value); } static void SetReg(byte *p_reg, int value) { *p_reg = (byte)value; Z = (*p_reg == 0); N = ((*p_reg & 0x80) != 0); } static void SetA(int value) { SetReg(&A, value); } static void SetX(int value) { SetReg(&X, value); } static void SetY(int value) { SetReg(&Y, value); } static void SBC(byte value) { if (D) { int A_dec = (A & 0xF) + ((A >> 4) * 10); int value_dec = (value & 0xF) + ((value >> 4) * 10); int result_dec = A_dec - value_dec - (C ? 0 : 1); C = (result_dec >= 0); if (!C) result_dec = -result_dec; // absolute value int result = (result_dec % 10) | (((result_dec / 10) % 10) << 4); SetA(result); N = false; // undefined? V = false; // undefined? } else { byte result = Subtract(A, value, &V); SetA(result); } } static void ADC_OP(byte value) { int result; if (D) { int A_dec = (A & 0xF) + ((A >> 4) * 10); int value_dec = (value & 0xF) + ((value >> 4) * 10); int result_dec = A_dec + value_dec + (C ? 1 : 0); C = (result_dec > 99); result = (result_dec % 10) | (((result_dec / 10) % 10) << 4); SetA(result); Z = (result_dec == 0); // BCD quirk -- 100 doesn't set Z V = false; } else { bool A_old_neg = (A & 0x80) != 0; bool value_neg = (value & 0x80) != 0; result = A + value + (C ? 1 : 0); C = (result & 0x100) != 0; SetA(result); bool result_neg = (result & 0x80) != 0; V = (!A_old_neg && !value_neg && result_neg) // pos + pos = neg: overflow || (A_old_neg && value_neg && !result_neg); // neg + neg = pos: overflow } } static void ORA(int value) { SetA(A | value); } static void EOR(int value) { SetA(A ^ value); } static void AND(int value) { SetA(A & value); } static void BIT_OP(byte value) { Z = (A & value) == 0; N = (value & 0x80) != 0; V = (value & 0x40) != 0; } static byte ASL(int value) { C = (value & 0x80) != 0; value = (byte)(value << 1); Z = (value == 0); N = (value & 0x80) != 0; return (byte)value; } static byte LSR(int value) { C = (value & 0x01) != 0; value = (byte)(value >> 1); Z = (value == 0); N = false; return (byte)value; } static byte ROL(int value) { bool newC = (value & 0x80) != 0; value = (byte)((value << 1) | (C ? 1 : 0)); C = newC; Z = (value == 0); N = (value & 0x80) != 0; return (byte)value; } static byte ROR(int value) { bool newC = (value & 0x01) != 0; N = C; value = (byte)((value >> 1) | (C ? 0x80 : 0)); C = newC; Z = (value == 0); return (byte)value; } extern void Push(int value) { SetMemory((ushort)(0x100 + (S--)), (byte)value); } extern byte Pop(void) { return GetMemory((ushort)(0x100 + (++S))); } static void PLP() { int flags = Pop(); N = (flags & 0x80) != 0; V = (flags & 0x40) != 0; B = (flags & 0x10) != 0; D = (flags & 0x08) != 0; I = (flags & 0x04) != 0; Z = (flags & 0x02) != 0; C = (flags & 0x01) != 0; } static void PHA() { Push(A); } static void PLA() { SetA(Pop()); } static void CLC() { C = false; } static void CLD() { D = false; } static void CLI() { I = false; } static void CLV() { V = false; } static void SEC() { C = true; } static void SED() { D = true; } static void SEI() { I = true; } static byte INC(byte value) { ++value; Z = (value == 0); N = (value & 0x80) != 0; return (byte)value; } static void INX() { X = INC(X); } static void INY() { Y = INC(Y); } static byte DEC(byte value) { --value; Z = (value == 0); N = (value & 0x80) != 0; return (byte)value; } static void DEX() { X = DEC(X); } static void DEY() { Y = DEC(Y); } static void NOP() { } static void TXA() { SetReg(&A, X); } static void TAX() { SetReg(&X, A); } static void TYA() { SetReg(&A, Y); } static void TAY() { SetReg(&Y, A); } static void TXS() { S = X; } static void TSX() { SetReg(&X, S); } static ushort GetBR(ushort addr, bool *p_conditional, byte *p_bytes) { *p_conditional = true; *p_bytes = 2; sbyte offset = (sbyte)GetMemory((ushort)(addr + 1)); ushort addr2 = (ushort)(addr + 2 + offset); return addr2; } static void BR(bool branch, ushort *p_addr, bool *p_conditional, byte *p_bytes) { ushort addr2 = GetBR(*p_addr, p_conditional, p_bytes); if (branch) { *p_addr = addr2; *p_bytes = 0; // don't advance addr } } static void BPL(ushort *p_addr, bool *p_conditional, byte *p_bytes) { BR(!N, p_addr, p_conditional, p_bytes); } static void BMI(ushort *p_addr, bool *p_conditional, byte *p_bytes) { BR(N, p_addr, p_conditional, p_bytes); } static void BCC(ushort *p_addr, bool *p_conditional, byte *p_bytes) { BR(!C, p_addr, p_conditional, p_bytes); } static void BCS(ushort *p_addr, bool *p_conditional, byte *p_bytes) { BR(C, p_addr, p_conditional, p_bytes); } static void BVC(ushort *p_addr, bool *p_conditional, byte *p_bytes) { BR(!V, p_addr, p_conditional, p_bytes); } static void BVS(ushort *p_addr, bool *p_conditional, byte *p_bytes) { BR(V, p_addr, p_conditional, p_bytes); } static void BNE(ushort *p_addr, bool *p_conditional, byte *p_bytes) { BR(!Z, p_addr, p_conditional, p_bytes); } static void BEQ(ushort *p_addr, bool *p_conditional, byte *p_bytes) { BR(Z, p_addr, p_conditional, p_bytes); } static void JSR(ushort *p_addr, byte *p_bytes) { *p_bytes = 3; // for next calculation ushort addr2 = (ushort)(*p_addr + *p_bytes - 1); ushort addr3 = (ushort)(GetMemory((ushort)(*p_addr + 1)) | (GetMemory((ushort)(*p_addr + 2)) << 8)); Push(HI(addr2)); Push(LO(addr2)); *p_addr = addr3; *p_bytes = 0; // addr already changed } static void RTS(ushort *p_addr, byte *p_bytes) { byte lo = Pop(); byte hi = Pop(); *p_bytes = 1; // make sure caller increases addr by one *p_addr = (ushort)((hi << 8) | lo); } static void RTI(ushort *p_addr, byte *p_bytes) { PLP(); byte lo = Pop(); byte hi = Pop(); *p_bytes = 0; // make sure caller does not increase addr by one *p_addr = (ushort)((hi << 8) | lo); } static void JMP(ushort *p_addr, byte *p_bytes) { *p_bytes = 0; // caller should not advance address ushort addr2 = (ushort)(GetMemory((ushort)(*p_addr + 1)) | (GetMemory((ushort)(*p_addr + 2)) << 8)); *p_addr = addr2; } static void JMPIND(ushort *p_addr, byte *p_bytes) { *p_bytes = 0; // caller should not advance address ushort addr2 = (ushort)(GetMemory((ushort)(*p_addr + 1)) | (GetMemory((ushort)(*p_addr + 2)) << 8)); ushort addr3; if ((addr2 & 0xFF) == 0xFF) // JMP($XXFF) won't go over page boundary addr3 = (ushort)(GetMemory(addr2) | (GetMemory((ushort)(addr2 - 0xFF)) << 8)); // 6502 "bug" - will use XXFF and XX00 as source of address else addr3 = (ushort)(GetMemory(addr2) | (GetMemory((ushort)(addr2 + 1)) << 8)); *p_addr = addr3; } // "A:FF X:FF Y:FF S:FF P:XX-XXXXX" static void GetDisplayState(char *state, int state_size) { snprintf(state, state_size, "A:%02X X:%02X Y:%02X S:%02X P:%c%c-%c%c%c%c%c", A, X, Y, S, N ? 'N' : ' ', V ? 'V' : ' ', B ? 'B' : ' ', D ? 'D' : ' ', I ? 'I' : ' ', Z ? 'Z' : ' ', C ? 'C' : ' ' ); } static byte GetIndX(ushort addr, byte *p_bytes) { *p_bytes = 2; ushort addr2 = (ushort)(GetMemory((ushort)(addr + 1)) + X); return GetMemory((ushort)(GetMemory(addr2) | (GetMemory((ushort)(addr2 + 1)) << 8))); } static void SetIndX(byte value, ushort addr, byte *p_bytes) { *p_bytes = 2; ushort addr2 = (ushort)(GetMemory((ushort)(addr + 1)) + X); ushort addr3 = (ushort)(GetMemory(addr2) | (GetMemory((ushort)(addr2 + 1)) << 8)); SetMemory(addr3, value); } static byte GetIndY(ushort addr, byte *p_bytes) { *p_bytes = 2; ushort addr2 = (ushort)(GetMemory((ushort)(addr + 1))); ushort addr3 = (ushort)((GetMemory(addr2) | (GetMemory((ushort)(addr2 + 1)) << 8)) + Y); return GetMemory(addr3); } static void SetIndY(byte value, ushort addr, byte *p_bytes) { *p_bytes = 2; ushort addr2 = (ushort)(GetMemory((ushort)(addr + 1))); ushort addr3 = (ushort)((GetMemory(addr2) | (GetMemory((ushort)(addr2 + 1)) << 8)) + Y); SetMemory(addr3, value); } static byte GetZP(ushort addr, byte *p_bytes) { *p_bytes = 2; ushort addr2 = GetMemory((ushort)(addr + 1)); return GetMemory(addr2); } static void SetZP(byte value, ushort addr, byte *p_bytes) { *p_bytes = 2; ushort addr2 = GetMemory((ushort)(addr + 1)); SetMemory(addr2, value); } static byte GetZPX(ushort addr, byte *p_bytes) { *p_bytes = 2; ushort addr2 = GetMemory((ushort)(addr + 1)); return GetMemory((byte)(addr2 + X)); } static void SetZPX(byte value, ushort addr, byte *p_bytes) { *p_bytes = 2; ushort addr2 = GetMemory((ushort)(addr + 1)); SetMemory((byte)(addr2 + X), value); } static byte GetZPY(ushort addr, byte *p_bytes) { *p_bytes = 2; ushort addr2 = GetMemory((ushort)(addr + 1)); return GetMemory((byte)(addr2 + Y)); } static void SetZPY(byte value, ushort addr, byte *p_bytes) { *p_bytes = 2; ushort addr2 = GetMemory((ushort)(addr + 1)); SetMemory((byte)(addr2 + Y), value); } static byte GetABS(ushort addr, byte *p_bytes) { *p_bytes = 3; ushort addr2 = (ushort)(GetMemory((ushort)(addr + 1)) | (GetMemory((ushort)(addr + 2)) << 8)); return GetMemory(addr2); } static void SetABS(byte value, ushort addr, byte *p_bytes) { *p_bytes = 3; ushort addr2 = (ushort)(GetMemory((ushort)(addr + 1)) | (GetMemory((ushort)(addr + 2)) << 8)); SetMemory(addr2, value); } static byte GetABSX(ushort addr, byte *p_bytes) { *p_bytes = 3; ushort addr2 = (ushort)(GetMemory((ushort)(addr + 1)) | (GetMemory((ushort)(addr + 2)) << 8)); return GetMemory((ushort)(addr2 + X)); } static void SetABSX(byte value, ushort addr, byte *p_bytes) { *p_bytes = 3; ushort addr2 = (ushort)((GetMemory((ushort)(addr + 1)) | (GetMemory((ushort)(addr + 2)) << 8)) + X); SetMemory(addr2, value); } static byte GetABSY(ushort addr, byte *p_bytes) { *p_bytes = 3; ushort addr2 = (ushort)(GetMemory((ushort)(addr + 1)) | (GetMemory((ushort)(addr + 2)) << 8)); return GetMemory((ushort)(addr2 + Y)); } static void SetABSY(byte value, ushort addr, byte *p_bytes) { *p_bytes = 3; ushort addr2 = (ushort)((GetMemory((ushort)(addr + 1)) | (GetMemory((ushort)(addr + 2)) << 8)) + Y); SetMemory(addr2, value); } static byte GetIM(ushort addr, byte *p_bytes) { *p_bytes = 2; return GetMemory((ushort)(addr + 1)); } extern void Execute(ushort addr, bool (*ExecutePatch)(void)) { bool conditional; byte bytes; #if (USE_IRQ == 1) // IRQ support Timer timer; const double interrupt_time = 1.0 / 60.0 ; // 60 times per second timer.start(); double timer_then = timer.read(); #endif PC = addr; while (true) { while (true) { #if (USE_IRQ == 1) if (!I && (timer.read()-timer_then) >= interrupt_time) // IRQ { timer_then = timer.read(); // reset timer Push(HI(PC)); Push(LO(PC)); PHP(); I = true; PC = (GetMemory(0xfffe) | (GetMemory(0xffff) << 8)); } else #endif { bytes = 1; bool breakpoint = false; //if (Breakpoints.Contains(PC)) // breakpoint = true; if (trace || breakpoint || step) { ushort addr2; char line[27]; char dis[13]; DisassembleLong(PC, &conditional, &bytes, &addr2, dis, sizeof(dis), line, sizeof(line)); char state[33]; GetDisplayState(state, sizeof(state)); char full_line[80]; snprintf(full_line, sizeof(full_line), "%-30s%s\n", line, state); #ifdef WIN32 OutputDebugStringA(full_line); #else pc.printf("%s", full_line); #endif if (step) step = step; // user can put debug breakpoint here to allow stepping if (breakpoint) breakpoint = breakpoint; // user can put debug breakpoint here to allow break } if (ExecutePatch != 0 && !ExecutePatch()) // allow execute to be overriden at a specific address break; } } switch (GetMemory(PC)) { case 0x00: BRK(&bytes); break; case 0x01: ORA(GetIndX(PC, &bytes)); break; case 0x05: ORA(GetZP(PC, &bytes)); break; case 0x06: SetZP(ASL(GetZP(PC, &bytes)), PC, &bytes); break; case 0x08: PHP(); break; case 0x09: ORA(GetIM(PC, &bytes)); break; case 0x0A: SetA(ASL(A)); break; case 0x0D: ORA(GetABS(PC, &bytes)); break; case 0x0E: SetABS(ASL(GetABS(PC, &bytes)), PC, &bytes); break; case 0x10: BPL(&PC, &conditional, &bytes); break; case 0x11: ORA(GetIndY(PC, &bytes)); break; case 0x15: ORA(GetZPX(PC, &bytes)); break; case 0x16: SetZPX(ASL(GetZPX(PC, &bytes)), PC, &bytes); break; case 0x18: CLC(); break; case 0x19: ORA(GetABSY(PC, &bytes)); break; case 0x1D: ORA(GetABSX(PC, &bytes)); break; case 0x1E: SetABSX(ASL(GetABSX(PC, &bytes)), PC, &bytes); break; case 0x20: JSR(&PC, &bytes); break; case 0x21: AND(GetIndX(PC, &bytes)); break; case 0x24: BIT_OP(GetZP(PC, &bytes)); break; case 0x25: AND(GetZP(PC, &bytes)); break; case 0x26: SetZP(ROL(GetZP(PC, &bytes)), PC, &bytes); break; case 0x28: PLP(); break; case 0x29: AND(GetIM(PC, &bytes)); break; case 0x2A: SetA(ROL(A)); break; case 0x2C: BIT_OP(GetABS(PC, &bytes)); break; case 0x2D: AND(GetABS(PC, &bytes)); break; case 0x2E: ROL(GetABS(PC, &bytes)); break; case 0x30: BMI(&PC, &conditional, &bytes); break; case 0x31: AND(GetIndY(PC, &bytes)); break; case 0x35: AND(GetZPX(PC, &bytes)); break; case 0x36: SetZPX(ROL(GetZPX(PC, &bytes)), PC, &bytes); break; case 0x38: SEC(); break; case 0x39: AND(GetABSY(PC, &bytes)); break; case 0x3D: AND(GetABSX(PC, &bytes)); break; case 0x3E: SetABSX(ROL(GetABSX(PC, &bytes)), PC, &bytes); break; case 0x40: RTI(&PC, &bytes); break; case 0x41: EOR(GetIndX(PC, &bytes)); break; case 0x45: EOR(GetZP(PC, &bytes)); break; case 0x46: SetZP(LSR(GetZP(PC, &bytes)), PC, &bytes); break; case 0x48: PHA(); break; case 0x49: EOR(GetIM(PC, &bytes)); break; case 0x4A: SetA(LSR(A)); break; case 0x4C: JMP(&PC, &bytes); break; case 0x4D: EOR(GetABS(PC, &bytes)); break; case 0x4E: LSR(GetABS(PC, &bytes)); break; case 0x50: BVC(&PC, &conditional, &bytes); break; case 0x51: EOR(GetIndY(PC, &bytes)); break; case 0x55: EOR(GetZPX(PC, &bytes)); break; case 0x56: SetZPX(LSR(GetZPX(PC, &bytes)), PC, &bytes); break; case 0x58: CLI(); break; case 0x59: EOR(GetABSY(PC, &bytes)); break; case 0x5D: EOR(GetABSX(PC, &bytes)); break; case 0x5E: SetABSX(LSR(GetABSX(PC, &bytes)), PC, &bytes); break; case 0x60: RTS(&PC, &bytes); break; case 0x61: ADC_OP(GetIndX(PC, &bytes)); break; case 0x65: ADC_OP(GetZP(PC, &bytes)); break; case 0x66: SetZP(ROR(GetZP(PC, &bytes)), PC, &bytes); break; case 0x68: PLA(); break; case 0x69: ADC_OP(GetIM(PC, &bytes)); break; case 0x6A: SetA(ROR(A)); break; case 0x6C: JMPIND(&PC, &bytes); break; case 0x6D: ADC_OP(GetABS(PC, &bytes)); break; case 0x6E: SetABS(ROR(GetABS(PC, &bytes)), PC, &bytes); break; case 0x70: BVS(&PC, &conditional, &bytes); break; case 0x71: ADC_OP(GetIndY(PC, &bytes)); break; case 0x75: ADC_OP(GetZPX(PC, &bytes)); break; case 0x76: SetZPX(ROR(GetZPX(PC, &bytes)), PC, &bytes); break; case 0x78: SEI(); break; case 0x79: ADC_OP(GetABSY(PC, &bytes)); break; case 0x7D: ADC_OP(GetABSX(PC, &bytes)); break; case 0x7E: SetABSX(ROR(GetABSX(PC, &bytes)), PC, &bytes); break; case 0x81: SetIndX(A, PC, &bytes); break; case 0x84: SetZP(Y, PC, &bytes); break; case 0x85: SetZP(A, PC, &bytes); break; case 0x86: SetZP(X, PC, &bytes); break; case 0x88: DEY(); break; case 0x8A: TXA(); break; case 0x8C: SetABS(Y, PC, &bytes); break; case 0x8D: SetABS(A, PC, &bytes); break; case 0x8E: SetABS(X, PC, &bytes); break; case 0x90: BCC(&PC, &conditional, &bytes); break; case 0x91: SetIndY(A, PC, &bytes); break; case 0x94: SetZPX(Y, PC, &bytes); break; case 0x95: SetZPX(A, PC, &bytes); break; case 0x96: SetZPY(X, PC, &bytes); break; case 0x98: TYA(); break; case 0x99: SetABSY(A, PC, &bytes); break; case 0x9A: TXS(); break; case 0x9D: SetABSX(A, PC, &bytes); break; case 0xA0: SetY(GetIM(PC, &bytes)); break; case 0xA1: SetA(GetIndX(PC, &bytes)); break; case 0xA2: SetX(GetIM(PC, &bytes)); break; case 0xA4: SetY(GetZP(PC, &bytes)); break; case 0xA5: SetA(GetZP(PC, &bytes)); break; case 0xA6: SetX(GetZP(PC, &bytes)); break; case 0xA8: TAY(); break; case 0xA9: SetA(GetIM(PC, &bytes)); break; case 0xAA: TAX(); break; case 0xAC: SetY(GetABS(PC, &bytes)); break; case 0xAD: SetA(GetABS(PC, &bytes)); break; case 0xAE: SetX(GetABS(PC, &bytes)); break; case 0xB0: BCS(&PC, &conditional, &bytes); break; case 0xB1: SetA(GetIndY(PC, &bytes)); break; case 0xB4: SetY(GetZPX(PC, &bytes)); break; case 0xB5: SetA(GetZPX(PC, &bytes)); break; case 0xB6: SetX(GetZPY(PC, &bytes)); break; case 0xB8: CLV(); break; case 0xB9: SetA(GetABSY(PC, &bytes)); break; case 0xBA: TSX(); break; case 0xBC: SetY(GetABSX(PC, &bytes)); break; case 0xBD: SetA(GetABSX(PC, &bytes)); break; case 0xBE: SetX(GetABSY(PC, &bytes)); break; case 0xC0: CPY(GetIM(PC, &bytes)); break; case 0xC1: CMP(GetIndX(PC, &bytes)); break; case 0xC4: CPY(GetZP(PC, &bytes)); break; case 0xC5: CMP(GetZP(PC, &bytes)); break; case 0xC6: SetZP(DEC(GetZP(PC, &bytes)), PC, &bytes); break; case 0xC8: INY(); break; case 0xC9: CMP(GetIM(PC, &bytes)); break; case 0xCA: DEX(); break; case 0xCC: CPY(GetABS(PC, &bytes)); break; case 0xCD: CMP(GetABS(PC, &bytes)); break; case 0xCE: SetABS(DEC(GetABS(PC, &bytes)), PC, &bytes); break; case 0xD0: BNE(&PC, &conditional, &bytes); break; case 0xD1: CMP(GetIndY(PC, &bytes)); break; case 0xD5: CMP(GetZPX(PC, &bytes)); break; case 0xD6: SetZPX(DEC(GetZPX(PC, &bytes)), PC, &bytes); break; case 0xD8: CLD(); break; case 0xD9: CMP(GetABSY(PC, &bytes)); break; case 0xDD: CMP(GetABSX(PC, &bytes)); break; case 0xDE: SetABSX(DEC(GetABSX(PC, &bytes)), PC, &bytes); break; case 0xE0: CPX(GetIM(PC, &bytes)); break; case 0xE1: SBC(GetIndX(PC, &bytes)); break; case 0xE4: CPX(GetZP(PC, &bytes)); break; case 0xE5: SBC(GetZP(PC, &bytes)); break; case 0xE6: SetZP(INC(GetZP(PC, &bytes)), PC, &bytes); break; case 0xE8: INX(); break; case 0xE9: SBC(GetIM(PC, &bytes)); break; case 0xEA: NOP(); break; case 0xEC: CPX(GetABS(PC, &bytes)); break; case 0xED: SBC(GetABS(PC, &bytes)); break; case 0xEE: SetABS(INC(GetABS(PC, &bytes)), PC, &bytes); break; case 0xF0: BEQ(&PC, &conditional, &bytes); break; case 0xF1: SBC(GetIndY(PC, &bytes)); break; case 0xF5: SBC(GetZPX(PC, &bytes)); break; case 0xF6: SetZPX(INC(GetZPX(PC, &bytes)), PC, &bytes); break; case 0xF8: SED(); break; case 0xF9: SBC(GetABSY(PC, &bytes)); break; case 0xFD: SBC(GetABSX(PC, &bytes)); break; case 0xFE: SetABSX(INC(GetABSX(PC, &bytes)), PC, &bytes); break; default: { printf("Invalid opcode %02X at %04X", GetMemory(PC), PC); exit(1); } } PC += bytes; } } // Examples: // FFFF FF FF FF JMP ($FFFF) // FFFF FF FF FF LDA $FFFF,X extern void DisassembleLong(ushort addr, bool *p_conditional, byte *p_bytes, ushort *p_addr2, char *dis, int dis_size, char *line, int line_size) { DisassembleShort(addr, p_conditional, p_bytes, p_addr2, dis, dis_size); snprintf(line, line_size, "%04X ", addr); for (int i = 0; i < 3; ++i) { if (i < *p_bytes) snprintf(line+strlen(line), line_size-strlen(line), "%02X ", GetMemory((ushort)(addr + i))); else strcat_s(line, line_size, " "); } strcat_s(line, line_size, dis); } static void Ind(char *dis, int dis_size, char* opcode, ushort addr, ushort *p_addr2, byte *p_bytes) { *p_bytes = 3; ushort addr1 = (ushort)(GetMemory((ushort)(addr + 1)) | (GetMemory((ushort)(addr + 2)) << 8)); *p_addr2 = (ushort)(GetMemory(addr1) | (GetMemory((ushort)(addr1 + 1)) << 8)); snprintf(dis, dis_size, "%s ($%0X4)", opcode, addr1); } static void IndX(char *dis, int dis_size, char* opcode, ushort addr, byte *p_bytes) { *p_bytes = 2; snprintf(dis, dis_size, "%s ($%02X,X)", opcode, GetMemory((ushort)(addr + 1))); } static void IndY(char *dis, int dis_size, char* opcode, ushort addr, byte *p_bytes) { *p_bytes = 2; snprintf(dis, dis_size, "%s ($%02X),Y", opcode, GetMemory((ushort)(addr + 1))); } static void ZP(char *dis, int dis_size, char* opcode, ushort addr, byte *p_bytes) { *p_bytes = 2; snprintf(dis, dis_size, "%s $%02X", opcode, GetMemory((ushort)(addr + 1))); } static void ZPX(char *dis, int dis_size, char* opcode, ushort addr, byte *p_bytes) { *p_bytes = 2; snprintf(dis, dis_size, "%s $%02X,X", opcode, GetMemory((ushort)(addr + 1))); } static void ZPY(char *dis, int dis_size, char* opcode, ushort addr, byte *p_bytes) { *p_bytes = 2; snprintf(dis, dis_size, "%s $%02X,Y", opcode, GetMemory((ushort)(addr + 1))); } static void ABS(char *dis, int dis_size, char* opcode, ushort addr, byte *p_bytes) { *p_bytes = 3; snprintf(dis, dis_size, "%s $%04X", opcode, GetMemory((ushort)(addr + 1)) | (GetMemory((ushort)(addr + 2)) << 8)); } static void ABSAddr(char *dis, int dis_size, char* opcode, ushort addr, ushort *p_addr2, byte *p_bytes) { *p_bytes = 3; *p_addr2 = (ushort)(GetMemory((ushort)(addr + 1)) | (GetMemory((ushort)(addr + 2)) << 8)); snprintf(dis, dis_size, "%s $%04X", opcode, *p_addr2); } static void ABSX(char *dis, int dis_size, char* opcode, ushort addr, byte *p_bytes) { *p_bytes = 3; snprintf(dis, dis_size, "%s $%04X,X", opcode, GetMemory((ushort)(addr + 1)) | (GetMemory((ushort)(addr + 2)) << 8)); } static void ABSY(char *dis, int dis_size, char* opcode, ushort addr, byte *p_bytes) { *p_bytes = 3; snprintf(dis, dis_size, "%s $%04X,Y", opcode, GetMemory((ushort)(addr + 1)) | (GetMemory((ushort)(addr + 2)) << 8)); } static void IM(char *dis, int dis_size, char* opcode, ushort addr, byte *p_bytes) { *p_bytes = 2; snprintf(dis, dis_size, "%s #$%02X", opcode, GetMemory((ushort)(addr + 1))); } static void BRX(char *dis, int dis_size, char* opcode, ushort addr, bool *p_conditional, ushort *p_addr2, byte *p_bytes) { *p_bytes = 2; *p_conditional = true; sbyte offset = (sbyte)GetMemory((ushort)(addr + 1)); *p_addr2 = (ushort)(addr + 2 + offset); snprintf(dis, dis_size, "%s $%04X", opcode, *p_addr2); } // JMP ($FFFF) // LDA $FFFF,X extern void DisassembleShort(ushort addr, bool *p_conditional, byte *p_bytes, ushort *p_addr2, char *dis, int dis_size) { *p_conditional = false; *p_addr2 = 0; *p_bytes = 1; switch (GetMemory(addr)) { case 0x00: strcpy_s(dis, dis_size, "BRK"); return; case 0x01: IndX(dis, dis_size, "ORA", addr, p_bytes); return; case 0x05: ZP(dis, dis_size, "ORA", addr, p_bytes); return; case 0x06: ZP(dis, dis_size, "ASL", addr, p_bytes); return; case 0x08: strcpy_s(dis, dis_size, "PHP"); return; case 0x09: IM(dis, dis_size, "ORA", addr, p_bytes); return; case 0x0A: strcpy_s(dis, dis_size, "ASL A"); return; case 0x0D: ABS(dis, dis_size, "ORA", addr, p_bytes); return; case 0x0E: ABS(dis, dis_size, "ASL", addr, p_bytes); return; case 0x10: BRX(dis, dis_size, "BPL", addr, p_conditional, p_addr2, p_bytes); return; case 0x11: IndY(dis, dis_size, "ORA", addr, p_bytes); return; case 0x15: ZPX(dis, dis_size, "ORA", addr, p_bytes); return; case 0x16: ZPX(dis, dis_size, "ASL", addr, p_bytes); return; case 0x18: strcpy_s(dis, dis_size, "CLC"); return; case 0x19: ABSY(dis, dis_size, "ORA", addr, p_bytes); return; case 0x1D: ABSX(dis, dis_size, "ORA", addr, p_bytes); return; case 0x1E: ABSX(dis, dis_size, "ASL", addr, p_bytes); return; case 0x20: ABSAddr(dis, dis_size, "JSR", addr, p_addr2, p_bytes); return; case 0x21: IndX(dis, dis_size, "AND", addr, p_bytes); return; case 0x24: ZP(dis, dis_size, "BIT", addr, p_bytes); return; case 0x25: ZP(dis, dis_size, "AND", addr, p_bytes); return; case 0x26: ZP(dis, dis_size, "ROL", addr, p_bytes); return; case 0x28: strcpy_s(dis, dis_size, "PLP"); return; case 0x29: IM(dis, dis_size, "AND", addr, p_bytes); return; case 0x2A: strcpy_s(dis, dis_size, "ROL A"); return; case 0x2C: ABS(dis, dis_size, "BIT", addr, p_bytes); return; case 0x2D: ABS(dis, dis_size, "AND", addr, p_bytes); return; case 0x2E: ABS(dis, dis_size, "ROL", addr, p_bytes); return; case 0x30: BRX(dis, dis_size, "BMI", addr, p_conditional, p_addr2, p_bytes); return; case 0x31: IndY(dis, dis_size, "AND", addr, p_bytes); return; case 0x35: ZPX(dis, dis_size, "AND", addr, p_bytes); return; case 0x36: ZPX(dis, dis_size, "ROL", addr, p_bytes); return; case 0x38: strcpy_s(dis, dis_size, "SEC"); return; case 0x39: ABSY(dis, dis_size, "AND", addr, p_bytes); return; case 0x3D: ABSX(dis, dis_size, "AND", addr, p_bytes); return; case 0x3E: ABSX(dis, dis_size, "ROL", addr, p_bytes); return; case 0x40: strcpy_s(dis, dis_size, "RTI"); return; case 0x41: IndX(dis, dis_size, "EOR", addr, p_bytes); return; case 0x45: ZP(dis, dis_size, "EOR", addr, p_bytes); return; case 0x46: ZP(dis, dis_size, "LSR", addr, p_bytes); return; case 0x48: strcpy_s(dis, dis_size, "PHA"); return; case 0x49: IM(dis, dis_size, "EOR", addr, p_bytes); return; case 0x4A: strcpy_s(dis, dis_size, "LSR A"); return; case 0x4C: ABSAddr(dis, dis_size, "JMP", addr, p_addr2, p_bytes); return; case 0x4D: ABS(dis, dis_size, "EOR", addr, p_bytes); return; case 0x4E: ABS(dis, dis_size, "LSR", addr, p_bytes); return; case 0x50: BRX(dis, dis_size, "BVC", addr, p_conditional, p_addr2, p_bytes); return; case 0x51: IndY(dis, dis_size, "EOR", addr, p_bytes); return; case 0x55: ZPX(dis, dis_size, "EOR", addr, p_bytes); return; case 0x56: ZPX(dis, dis_size, "LSR", addr, p_bytes); return; case 0x58: strcpy_s(dis, dis_size, "CLI"); return; case 0x59: ABSY(dis, dis_size, "EOR", addr, p_bytes); return; case 0x5D: ABSX(dis, dis_size, "EOR", addr, p_bytes); return; case 0x5E: ABSX(dis, dis_size, "LSR", addr, p_bytes); return; case 0x60: strcpy_s(dis, dis_size, "RTS"); return; case 0x61: IndX(dis, dis_size, "ADC", addr, p_bytes); return; case 0x65: ZP(dis, dis_size, "ADC", addr, p_bytes); return; case 0x66: ZP(dis, dis_size, "ROR", addr, p_bytes); return; case 0x68: strcpy_s(dis, dis_size, "PLA"); return; case 0x69: IM(dis, dis_size, "ADC", addr, p_bytes); return; case 0x6A: strcpy_s(dis, dis_size, "ROR A"); return; case 0x6C: Ind(dis, dis_size, "JMP", addr, p_addr2, p_bytes); return; case 0x6D: ABS(dis, dis_size, "ADC", addr, p_bytes); return; case 0x6E: ABS(dis, dis_size, "ROR", addr, p_bytes); return; case 0x70: BRX(dis, dis_size, "BVS", addr, p_conditional, p_addr2, p_bytes); return; case 0x71: IndY(dis, dis_size, "ADC", addr, p_bytes); return; case 0x75: ZPX(dis, dis_size, "ADC", addr, p_bytes); return; case 0x76: ZPX(dis, dis_size, "ROR", addr, p_bytes); return; case 0x78: strcpy_s(dis, dis_size, "SEI"); return; case 0x79: ABSY(dis, dis_size, "ADC", addr, p_bytes); return; case 0x7D: ABSX(dis, dis_size, "ADC", addr, p_bytes); return; case 0x7E: ABSX(dis, dis_size, "ROR", addr, p_bytes); return; case 0x81: IndX(dis, dis_size, "STA", addr, p_bytes); return; case 0x84: ZP(dis, dis_size, "STY", addr, p_bytes); return; case 0x85: ZP(dis, dis_size, "STA", addr, p_bytes); return; case 0x86: ZP(dis, dis_size, "STX", addr, p_bytes); return; case 0x88: strcpy_s(dis, dis_size, "DEY"); return; case 0x8A: strcpy_s(dis, dis_size, "TXA"); return; case 0x8C: ABS(dis, dis_size, "STY", addr, p_bytes); return; case 0x8D: ABS(dis, dis_size, "STA", addr, p_bytes); return; case 0x8E: ABS(dis, dis_size, "STX", addr, p_bytes); return; case 0x90: BRX(dis, dis_size, "BCC", addr, p_conditional, p_addr2, p_bytes); return; case 0x91: IndY(dis, dis_size, "STA", addr, p_bytes); return; case 0x94: ZPX(dis, dis_size, "STY", addr, p_bytes); return; case 0x95: ZPX(dis, dis_size, "STA", addr, p_bytes); return; case 0x96: ZPY(dis, dis_size, "STX", addr, p_bytes); return; case 0x98: strcpy_s(dis, dis_size, "TYA"); return; case 0x99: ABSY(dis, dis_size, "STA", addr, p_bytes); return; case 0x9A: strcpy_s(dis, dis_size, "TXS"); return; case 0x9D: ABSX(dis, dis_size, "STA", addr, p_bytes); return; case 0xA0: IM(dis, dis_size, "LDY", addr, p_bytes); return; case 0xA1: IndX(dis, dis_size, "LDA", addr, p_bytes); return; case 0xA2: IM(dis, dis_size, "LDX", addr, p_bytes); return; case 0xA4: ZP(dis, dis_size, "LDY", addr, p_bytes); return; case 0xA5: ZP(dis, dis_size, "LDA", addr, p_bytes); return; case 0xA6: ZP(dis, dis_size, "LDX", addr, p_bytes); return; case 0xA8: strcpy_s(dis, dis_size, "TAY"); return; case 0xA9: IM(dis, dis_size, "LDA", addr, p_bytes); return; case 0xAA: strcpy_s(dis, dis_size, "TAX"); return; case 0xAC: ABS(dis, dis_size, "LDY", addr, p_bytes); return; case 0xAD: ABS(dis, dis_size, "LDA", addr, p_bytes); return; case 0xAE: ABS(dis, dis_size, "LDX", addr, p_bytes); return; case 0xB0: BRX(dis, dis_size, "BCS", addr, p_conditional, p_addr2, p_bytes); return; case 0xB1: IndY(dis, dis_size, "LDA", addr, p_bytes); return; case 0xB4: ZPX(dis, dis_size, "LDY", addr, p_bytes); return; case 0xB5: ZPX(dis, dis_size, "LDA", addr, p_bytes); return; case 0xB6: ZPY(dis, dis_size, "LDX", addr, p_bytes); return; case 0xB8: strcpy_s(dis, dis_size, "CLV"); return; case 0xB9: ABSY(dis, dis_size, "LDA", addr, p_bytes); return; case 0xBA: strcpy_s(dis, dis_size, "TSX"); return; case 0xBC: ABSX(dis, dis_size, "LDY", addr, p_bytes); return; case 0xBD: ABSX(dis, dis_size, "LDA", addr, p_bytes); return; case 0xBE: ABSY(dis, dis_size, "LDX", addr, p_bytes); return; case 0xC0: IM(dis, dis_size, "CPY", addr, p_bytes); return; case 0xC1: IndX(dis, dis_size, "CMP", addr, p_bytes); return; case 0xC4: ZP(dis, dis_size, "CPY", addr, p_bytes); return; case 0xC5: ZP(dis, dis_size, "CMP", addr, p_bytes); return; case 0xC6: ZP(dis, dis_size, "DEC", addr, p_bytes); return; case 0xC8: strcpy_s(dis, dis_size, "INY"); return; case 0xC9: IM(dis, dis_size, "CMP", addr, p_bytes); return; case 0xCA: strcpy_s(dis, dis_size, "DEX"); return; case 0xCC: ABS(dis, dis_size, "CPY", addr, p_bytes); return; case 0xCD: ABS(dis, dis_size, "CMP", addr, p_bytes); return; case 0xCE: ABS(dis, dis_size, "DEC", addr, p_bytes); return; case 0xD0: BRX(dis, dis_size, "BNE", addr, p_conditional, p_addr2, p_bytes); return; case 0xD1: IndY(dis, dis_size, "CMP", addr, p_bytes); return; case 0xD5: ZPX(dis, dis_size, "CMP", addr, p_bytes); return; case 0xD6: ZPX(dis, dis_size, "DEC", addr, p_bytes); return; case 0xD8: strcpy_s(dis, dis_size, "CLD"); return; case 0xD9: ABSY(dis, dis_size, "CMP", addr, p_bytes); return; case 0xDD: ABSX(dis, dis_size, "CMP", addr, p_bytes); return; case 0xDE: ABSX(dis, dis_size, "DEC", addr, p_bytes); return; case 0xE0: IM(dis, dis_size, "CPX", addr, p_bytes); return; case 0xE1: IndX(dis, dis_size, "SBC", addr, p_bytes); return; case 0xE4: ZP(dis, dis_size, "CPX", addr, p_bytes); return; case 0xE5: ZP(dis, dis_size, "SBC", addr, p_bytes); return; case 0xE6: ZP(dis, dis_size, "INC", addr, p_bytes); return; case 0xE8: strcpy_s(dis, dis_size, "INX"); return; case 0xE9: IM(dis, dis_size, "SBC", addr, p_bytes); return; case 0xEA: strcpy_s(dis, dis_size, "NOP"); return; case 0xEC: ABS(dis, dis_size, "CPX", addr, p_bytes); return; case 0xED: ABS(dis, dis_size, "SBC", addr, p_bytes); return; case 0xEE: ABS(dis, dis_size, "INC", addr, p_bytes); return; case 0xF0: BRX(dis, dis_size, "BEQ", addr, p_conditional, p_addr2, p_bytes); return; case 0xF1: IndY(dis, dis_size, "SBC", addr, p_bytes); return; case 0xF5: ZPX(dis, dis_size, "SBC", addr, p_bytes); return; case 0xF6: ZPX(dis, dis_size, "INC", addr, p_bytes); return; case 0xF8: strcpy_s(dis, dis_size, "SED"); return; case 0xF9: ABSY(dis, dis_size, "SBC", addr, p_bytes); return; case 0xFD: ABSX(dis, dis_size, "SBC", addr, p_bytes); return; case 0xFE: ABSX(dis, dis_size, "INC", addr, p_bytes); return; default: strcpy_s(dis, dis_size, "???"); return; //throw new Exception(string.Format("Invalid opcode {0:X2}", memory[addr])); } }