emu6502/disassembler.c

#include "types.h"
#include "opcodes.h"
#include "disassembler.h"
#include <stdio.h>

void disassemble_6502(byte* buffer, word pc) {
	printf("%04d  ", pc);
	byte* code = &buffer[pc];
	int bytes = 1;
	char op[128] = "";
	switch (*code) {

	case ADC_IMM: sprintf(op, "ADC #$%02X", code[1]); bytes = 2; break;
	case ADC_ZP: sprintf(op, "ADC $%02X", code[1]); bytes = 2; break;
	case ADC_ZPX: sprintf(op, "ADC $%02X,X", code[1]); bytes = 2; break;
	case ADC_ABS: sprintf(op, "ADC $%02X%02X", code[2], code[1]); bytes = 3; break;
	case ADC_ABSX: sprintf(op, "ADC $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case ADC_ABSY: sprintf(op, "ADC $%02X%02X,Y", code[2], code[1]); bytes = 3; break;
	case ADC_INDX: sprintf(op, "ADC ($%02X,X)", code[1]); bytes = 2; break;
	case ADC_INDY: sprintf(op, "ADC ($%02X),Y", code[1]); bytes = 2; break;
	case AND_IMM: sprintf(op, "AND #$%02X", code[1]); bytes = 2; break;
	case AND_ZP: sprintf(op, "AND $%02X", code[1]); bytes = 2; break;
	case AND_ZPX: sprintf(op, "AND $%02X,X", code[1]); bytes = 2; break;
	case AND_ABS: sprintf(op, "AND $%02X%02X", code[2], code[1]); bytes = 3; break;
	case AND_ABSX: sprintf(op, "AND $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case AND_ABSY: sprintf(op, "AND $%02X%02X,Y", code[2], code[1]); bytes = 3; break;
	case AND_INDX: sprintf(op, "AND ($%02X,X)", code[1]); bytes = 2; break;
	case AND_INDY: sprintf(op, "AND ($%02X),Y", code[1]); bytes = 2; break;
	case ASL_ACC: sprintf(op, "ASL A"); break;
	case ASL_ZP: sprintf(op, "ASL $%02X", code[1]); bytes = 2; break;
	case ASL_ZPX: sprintf(op, "ASL $%02X,X", code[1]); bytes = 2; break;
	case ASL_ABS: sprintf(op, "ASL $%02X%02X", code[2], code[1]); bytes = 3; break;
	case ASL_ABSX: sprintf(op, "ASL $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case BCC_REL: sprintf(op, "BCC $%02X", code[1]); bytes = 2; break;
	case BCS_REL: sprintf(op, "BCS $%02X", code[1]); bytes = 2; break;
	case BEQ_REL: sprintf(op, "BEQ $%02X", code[1]); bytes = 2; break;
	case BMI_REL: sprintf(op, "BMI $%02X", code[1]); bytes = 2; break;
	case BNE_REL: sprintf(op, "BNE $%02X", code[1]); bytes = 2; break;
	case BPL_REL: sprintf(op, "BPL $%02X", code[1]); bytes = 2; break;
	case BVC_REL: sprintf(op, "BVC $%02X", code[1]); bytes = 2; break;
	case BVS_REL: sprintf(op, "BVS $%02X", code[1]); bytes = 2; break;
	case BIT_ZP: sprintf(op, "BIT $%02X", code[1]); bytes = 2; break;
	case BIT_ABS: sprintf(op, "BIT $%02X%02X", code[2], code[1]); bytes = 3; break;
	case BRK: sprintf(op, "BRK"); break;
	case CLC: sprintf(op, "CLC"); break;
	case CLD: sprintf(op, "CLD"); break;
	case CLI: sprintf(op, "CLI"); break;
	case CLV: sprintf(op, "CLV"); break;
	case NOP: sprintf(op, "NOP"); break;
	case PHA: sprintf(op, "PHA"); break;
	case PLA: sprintf(op, "PLA"); break;
	case PHP: sprintf(op, "PHP"); break;
	case PLP: sprintf(op, "PLP"); break;
	case RTI: sprintf(op, "RTI"); break;
	case RTS: sprintf(op, "RTS"); break;
	case SEC: sprintf(op, "SEC"); break;
	case SED: sprintf(op, "SED"); break;
	case SEI: sprintf(op, "SEI"); break;
	case TAX: sprintf(op, "TAX"); break;
	case TXA: sprintf(op, "TXA"); break;
	case TAY: sprintf(op, "TAY"); break;
	case TYA: sprintf(op, "TYA"); break;
	case TSX: sprintf(op, "TSX"); break;
	case TXS: sprintf(op, "TXS"); break;
	case CMP_IMM: sprintf(op, "CMP #$%02X", code[1]); bytes = 2; break;
	case CMP_ZP: sprintf(op, "CMP $%02X", code[1]); bytes = 2; break;
	case CMP_ZPX: sprintf(op, "CMP $%02X,X", code[1]); bytes = 2; break;
	case CMP_ABS: sprintf(op, "CMP $%02X%02X", code[2], code[1]); bytes = 3; break;
	case CMP_ABSX: sprintf(op, "CMP $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case CMP_ABSY: sprintf(op, "CMP $%02X%02X,Y", code[2], code[1]); bytes = 3; break;
	case CMP_INDX: sprintf(op, "CMP ($%02X,X)", code[1]); bytes = 2; break;
	case CMP_INDY: sprintf(op, "CMP ($%02X),Y", code[1]); bytes = 2; break;
	case CPX_IMM: sprintf(op, "CPX #$%02X", code[1]); bytes = 2; break;
	case CPX_ZP: sprintf(op, "CPX $%02X", code[1]); bytes = 2; break;
	case CPX_ABS: sprintf(op, "CPX $%02X%02X", code[2], code[1]); bytes = 3; break;
	case CPY_IMM: sprintf(op, "CPY #$%02X", code[1]); bytes = 2; break;
	case CPY_ZP: sprintf(op, "CPY $%02X", code[1]); bytes = 2; break;
	case CPY_ABS: sprintf(op, "CPY $%02X%02X", code[2], code[1]); bytes = 3; break;
	case DEC_ZP: sprintf(op, "DEC $%02X", code[1]); bytes = 2; break;
	case DEC_ZPX: sprintf(op, "DEC $%02X,X", code[1]); bytes = 2; break;
	case DEC_ABS: sprintf(op, "DEC $%02X%02X", code[2], code[1]); bytes = 3; break;
	case DEC_ABSX: sprintf(op, "DEC $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case DEX: sprintf(op, "DEX"); break;
	case DEY: sprintf(op, "DEY"); break;
	case INX: sprintf(op, "INX"); break;
	case INY: sprintf(op, "INY"); break;
	case EOR_IMM: sprintf(op, "EOR #$%02X", code[1]); bytes = 2; break;
	case EOR_ZP: sprintf(op, "EOR $%02X", code[1]); bytes = 2; break;
	case EOR_ZPX: sprintf(op, "EOR $%02X,X", code[1]); bytes = 2; break;
	case EOR_ABS: sprintf(op, "EOR $%02X%02X", code[2], code[1]); bytes = 3; break;
	case EOR_ABSX: sprintf(op, "EOR $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case EOR_ABSY: sprintf(op, "EOR $%02X%02X,Y", code[2], code[1]); bytes = 3; break;
	case EOR_INDX: sprintf(op, "EOR ($%02X,X)", code[1]); bytes = 2; break;
	case EOR_INDY: sprintf(op, "EOR ($%02X),Y", code[1]); bytes = 2; break;
	case INC_ZP: sprintf(op, "INC $%02X", code[1]); bytes = 2; break;
	case INC_ZPX: sprintf(op, "INC $%02X,X", code[1]); bytes = 2; break;
	case INC_ABS: sprintf(op, "INC $%02X%02X", code[2], code[1]); bytes = 3; break;
	case INC_ABSX: sprintf(op, "INC $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case JMP_ABS: sprintf(op, "JMP $%02X%02X", code[2], code[1]); bytes = 3; break;
	case JMP_IND: sprintf(op, "JMP ($%02X%02X)", code[2], code[1]); bytes = 3; break;
	case JSR_ABS: sprintf(op, "JSR $%02X%02X", code[2], code[1]); bytes = 3; break;
	case LDA_IMM: sprintf(op, "LDA #$%02X", code[1]); bytes = 2; break;
	case LDA_ZP: sprintf(op, "LDA $%02X", code[1]); bytes = 2; break;
	case LDA_ZPX: sprintf(op, "LDA $%02X,X", code[1]); bytes = 2; break;
	case LDA_ABS: sprintf(op, "LDA $%02X%02X", code[2], code[1]); bytes = 3; break;
	case LDA_ABSX: sprintf(op, "LDA $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case LDA_ABSY: sprintf(op, "LDA $%02X%02X,Y", code[2], code[1]); bytes = 3; break;
	case LDA_INDX: sprintf(op, "LDA ($%02X,X)", code[1]); bytes = 2; break;
	case LDA_INDY: sprintf(op, "LDA ($%02X),Y", code[1]); bytes = 2; break;
	case LDX_IMM: sprintf(op, "LDX #$%02X", code[1]); bytes = 2; break;
	case LDX_ZP: sprintf(op, "LDX $%02X", code[1]); bytes = 2; break;
	case LDX_ZPY: sprintf(op, "LDX $%02X,Y", code[1]); bytes = 2; break;
	case LDX_ABS: sprintf(op, "LDX $%02X%02X", code[2], code[1]); bytes = 3; break;
	case LDX_ABSY: sprintf(op, "LDX $%02X%02X,Y", code[2], code[1]); bytes = 3; break;
	case LDY_IMM: sprintf(op, "LDY #$%02X", code[1]); bytes = 2; break;
	case LDY_ZP: sprintf(op, "LDY $%02X", code[1]); bytes = 2; break;
	case LDY_ZPX: sprintf(op, "LDY $%02X,X", code[1]); bytes = 2; break;
	case LDY_ABS: sprintf(op, "LDY $%02X%02X", code[2], code[1]); bytes = 3; break;
	case LDY_ABSX: sprintf(op, "LDY $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case LSR_ACC: sprintf(op, "LSR A"); break;
	case LSR_ZP: sprintf(op, "LSR $%02X", code[1]); bytes = 2; break;
	case LSR_ZPX: sprintf(op, "LSR $%02X,X", code[1]); bytes = 2; break;
	case LSR_ABS: sprintf(op, "LSR $%02X%02X", code[2], code[1]); bytes = 3; break;
	case LSR_ABSX: sprintf(op, "LSR $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case ORA_IMM: sprintf(op, "ORA #$%02X", code[1]); bytes = 2; break;
	case ORA_ZP: sprintf(op, "ORA $%02X", code[1]); bytes = 2; break;
	case ORA_ZPX: sprintf(op, "ORA $%02X,X", code[1]); bytes = 2; break;
	case ORA_ABS: sprintf(op, "ORA $%02X%02X", code[2], code[1]); bytes = 3; break;
	case ORA_ABSX: sprintf(op, "ORA $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case ORA_ABSY: sprintf(op, "ORA $%02X%02X,Y", code[2], code[1]); bytes = 3; break;
	case ORA_INDX: sprintf(op, "ORA ($%02X,X)", code[1]); bytes = 2; break;
	case ORA_INDY: sprintf(op, "ORA ($%02X),Y", code[1]); bytes = 2; break;
	case ROL_ACC: sprintf(op, "ROL A"); break;
	case ROL_ZP: sprintf(op, "ROL $%02X", code[1]); bytes = 2; break;
	case ROL_ZPX: sprintf(op, "ROL $%02X,X", code[1]); bytes = 2; break;
	case ROL_ABS: sprintf(op, "ROL $%02X%02X", code[2], code[1]); bytes = 3; break;
	case ROL_ABSX: sprintf(op, "ROL $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case ROR_ACC: sprintf(op, "ROR A"); break;
	case ROR_ZP: sprintf(op, "ROR $%02X", code[1]); bytes = 2; break;
	case ROR_ZPX: sprintf(op, "ROR $%02X,X", code[1]); bytes = 2; break;
	case ROR_ABS: sprintf(op, "ROR $%02X%02X", code[2], code[1]); bytes = 3; break;
	case ROR_ABSX: sprintf(op, "ROR $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case SBC_IMM: sprintf(op, "SBC #$%02X", code[1]); bytes = 2; break;
	case SBC_ZP: sprintf(op, "SBC $%02X", code[1]); bytes = 2; break;
	case SBC_ZPX: sprintf(op, "SBC $%02X,X", code[1]); bytes = 2; break;
	case SBC_ABS: sprintf(op, "SBC $%02X%02X", code[2], code[1]); bytes = 3; break;
	case SBC_ABSX: sprintf(op, "SBC $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case SBC_ABSY: sprintf(op, "SBC $%02X%02X,Y", code[2], code[1]); bytes = 3; break;
	case SBC_INDX: sprintf(op, "SBC ($%02X,X)", code[1]); bytes = 2; break;
	case SBC_INDY: sprintf(op, "SBC ($%02X),Y", code[1]); bytes = 2; break;
	case STA_ZP: sprintf(op, "STA $%02X", code[1]); bytes = 2; break;
	case STA_ZPX: sprintf(op, "STA $%02X,X", code[1]); bytes = 2; break;
	case STA_ABS: sprintf(op, "STA $%02X%02X", code[2], code[1]); bytes = 3; break;
	case STA_ABSX: sprintf(op, "STA $%02X%02X,X", code[2], code[1]); bytes = 3; break;
	case STA_ABSY: sprintf(op, "STA $%02X%02X,Y", code[2], code[1]); bytes = 3; break;
	case STA_INDX: sprintf(op, "STA ($%02X,X)", code[1]); bytes = 2; break;
	case STA_INDY: sprintf(op, "STA ($%02X),Y", code[1]); bytes = 2; break;
	case STX_ZP: sprintf(op, "STX $%02X", code[1]); bytes = 2; break;
	case STX_ZPY: sprintf(op, "STX $%02X,Y", code[1]); bytes = 2; break;
	case STX_ABS: sprintf(op, "STX $%02X%02X", code[2], code[1]); bytes = 3; break;
	case STY_ZP: sprintf(op, "STY $%02X", code[1]); bytes = 2; break;
	case STY_ZPX: sprintf(op, "STY $%02X,X", code[1]); bytes = 2; break;
	case STY_ABS: sprintf(op, "STY $%02X%02X", code[2], code[1]); bytes = 3; break;


	default:
		printf("UNKNOWN %02x", *code);
	}

	//print opcode
	printf("%02X ", *code);

	if (bytes > 1) {
		printf("%02x ", code[1]);
	}
	else {
		printf("   ");
	}
	if (bytes > 2) {
		printf("%02x ", code[2]);
	}
	else {
		printf("   ");
	}
	printf(op);

	printf("\n");
}