#include<stdio.h>
#include<stdlib.h>

// gcc disassembler.c -o disassembler

typedef struct buffer {
    unsigned char* buffer;
    int length;
} buffer;

buffer* read_file(char** argv) {
    FILE* file = fopen(argv[1], "rb");
    if (file == NULL) {
        printf("Issue opening the file.\n");
        return NULL;
    }

    //Get the file size and read it into a memory buffer    
    fseek(file, 0L, SEEK_END);    
    int fsize = ftell(file);    
    fseek(file, 0L, SEEK_SET);    

    buffer *b = malloc(sizeof(buffer));
    b->buffer=malloc(fsize);    
    b->length=fsize;

    fread(b->buffer, fsize, 1, file);    
    fclose(file);    

    return b;
}

void print_buffer(buffer* b) {
    for (int i = 0; i < 40; i++) {
        printf("%02x \n", b->buffer[i]);
    }
}

int disassemble8080(buffer* b, int pc) {
    unsigned char *code = &(b->buffer[pc]);
    int opbytes = 1;
    printf("%04x ", pc);
    switch (*code) {
        case 0x00: printf("NOP"); break;

        case 0x01: printf("LXI B,#$%02x%02x", code[2], code[1]); opbytes = 3; break;
        case 0x02: printf("STAX B"); break;
        case 0x03: printf("INX B"); break;
        case 0x04: printf("INR B"); break;
        case 0x05: printf("DCR B"); break;
        case 0x06: printf("MVI B,#$%02x", code[1]); opbytes = 2; break;
        case 0x07: printf("RLC"); break;
        case 0x08: printf("NOP"); break;

        case 0x09: printf("DAD B"); break;
        case 0x0a: printf("LDAX B"); break; 
        case 0x0b: printf("DCX B"); break;
        case 0x0c: printf("INR C"); break;
        case 0x0d: printf("DCR C"); break;
        case 0x0e: printf("MVI C,#$%02x", code[1]); opbytes = 2; break;
        case 0x0f: printf("RRC"); break;
        case 0x10: printf("NOP"); break;

        case 0x11: printf("LXI D,#$%02x%02x", code[2], code[1]); opbytes = 3; break;
        case 0x12: printf("STAX D"); break;
        case 0x13: printf("INX D"); break;
        case 0x14: printf("INR D"); break;
        case 0x15: printf("DCR D"); break;
        case 0x16: printf("MVI D,#$%02x", code[1]); opbytes = 2; break;
        case 0x17: printf("RAL"); break;
        case 0x18: printf("NOP"); break;

        case 0x19: printf("DAD D"); break;
        case 0x1a: printf("LDAX D"); break;
        case 0x1b: printf("DCX D"); break;
        case 0x1c: printf("INR E"); break;
        case 0x1d: printf("DCR E"); break;
        case 0x1e: printf("MVI E,#$%02x", code[1]); opbytes = 2; break;
        case 0x1f: printf("RAR"); break;
        case 0x20: printf("NOP"); break;

        case 0x21: printf("LXI H,#$%02x%02x", code[2], code[1]); opbytes = 3; break;
        case 0x22: printf("SHLD $%02x%02x", code[2], code[1]); opbytes = 3; break;
        case 0x23: printf("INX H"); break;
        case 0x24: printf("INR H"); break;
        case 0x25: printf("DCR H"); break;
        case 0x26: printf("MVI H,#$%02x", code[1]); opbytes = 2; break;
        case 0x27: printf("DAA"); break;
        case 0x28: printf("NOP"); break;

        case 0x29: printf("DAD H"); break;
        case 0x2a: printf("LHLD $%02x%02x", code[2], code[1]); opbytes = 3; break;
        case 0x2b: printf("DCX H"); break;
        case 0x2c: printf("INR L"); break;
        case 0x2d: printf("DCR L"); break;
        case 0x2e: printf("MVI L,#$%02x", code[1]); opbytes = 2; break;
        case 0x2f: printf("CMA"); break;
        case 0x30: printf("NOP"); break;

        case 0x31: printf("LXI SP,#$%02x%02x", code[2], code[1]); opbytes = 3; break;
        case 0x32: printf("STA $%02x%02x", code[2], code[1]); opbytes = 3; break;
        case 0x33: printf("INX SP"); break;
        case 0x34: printf("INR M"); break;
        case 0x35: printf("DCR M"); break;
        case 0x36: printf("MVI M,#$%02x", code[1]); opbytes = 2; break;
        case 0x37: printf("STC"); break;
        case 0x38: printf("NOP"); break;

        case 0x39: printf("DAD SP"); break;
        case 0x3a: printf("LDA $%02x%02x", code[2], code[1]); opbytes = 3; break;
        case 0x3b: printf("DCX SP"); break;
        case 0x3c: printf("INR A"); break;
        case 0x3d: printf("DCR A"); break;
        case 0x3e: printf("MVI A,#$%02x", code[1]); opbytes = 2; break;
        case 0x3f: printf("CMC"); break;

        case 0x40: printf("MOV B,B"); break;
        case 0x41: printf("MOV B,C"); break;
        case 0x42: printf("MOV B,D"); break;
        case 0x43: printf("MOV B,E"); break;
        case 0x44: printf("MOV B,H"); break;
        case 0x45: printf("MOV B,L"); break;
        case 0x46: printf("MOV B,M"); break;
        case 0x47: printf("MOV B,A"); break;

        case 0x48: printf("MOV C,B"); break;
        case 0x49: printf("MOV C,C"); break;
        case 0x4a: printf("MOV C,D"); break;
        case 0x4b: printf("MOV C,E"); break;
        case 0x4c: printf("MOV C,H"); break;
        case 0x4d: printf("MOV C,L"); break;
        case 0x4e: printf("MOV C,M"); break;
        case 0x4f: printf("MOV C,A"); break;

        case 0x50: printf("MOV D,B"); break;
        case 0x51: printf("MOV D,C"); break;
        case 0x52: printf("MOV D,D"); break;
        case 0x53: printf("MOV D,E"); break;
        case 0x54: printf("MOV D,H"); break;
        case 0x55: printf("MOV D,L"); break;
        case 0x56: printf("MOV D,M"); break;
        case 0x57: printf("MOV D,A"); break;

        case 0x58: printf("MOV E,B"); break;
        case 0x59: printf("MOV E,C"); break;
        case 0x5a: printf("MOV E,D"); break;
        case 0x5b: printf("MOV E,E"); break;
        case 0x5c: printf("MOV E,H"); break;
        case 0x5d: printf("MOV E,L"); break;
        case 0x5e: printf("MOV E,M"); break;
        case 0x5f: printf("MOV E,A"); break;

        case 0x60: printf("MOV H,B"); break;
        case 0x61: printf("MOV H,C"); break;
        case 0x62: printf("MOV H,D"); break;
        case 0x63: printf("MOV H,E"); break;
        case 0x64: printf("MOV H,H"); break;
        case 0x65: printf("MOV H,L"); break;
        case 0x66: printf("MOV H,M"); break;
        case 0x67: printf("MOV H,A"); break;

        case 0x68: printf("MOV L,B"); break;
        case 0x69: printf("MOV L,C"); break;
        case 0x6a: printf("MOV L,D"); break;
        case 0x6b: printf("MOV L,E"); break;
        case 0x6c: printf("MOV L,H"); break;
        case 0x6d: printf("MOV L,L"); break;
        case 0x6e: printf("MOV L,M"); break;
        case 0x6f: printf("MOV L,A"); break;

        case 0x70: printf("MOV M,B"); break;
        case 0x71: printf("MOV M,C"); break;
        case 0x72: printf("MOV M,D"); break;
        case 0x73: printf("MOV M,E"); break;
        case 0x74: printf("MOV M,H"); break;
        case 0x75: printf("MOV M,L"); break;
        case 0x76: printf("HLT"); break;
        case 0x77: printf("MOV M,A"); break;

        case 0x78: printf("MOV A,B"); break;
        case 0x79: printf("MOV A,C"); break;
        case 0x7a: printf("MOV A,D"); break;
        case 0x7b: printf("MOV A,E"); break;
        case 0x7c: printf("MOV A,H"); break;
        case 0x7d: printf("MOV A,L"); break;
        case 0x7e: printf("MOV A,M"); break;
        case 0x7f: printf("MOV A,A"); break;

        case 0x80: printf("ADD B"); break;
        case 0x81: printf("ADD C"); break;
        case 0x82: printf("ADD D"); break;
        case 0x83: printf("ADD E"); break;
        case 0x84: printf("ADD H"); break;
        case 0x85: printf("ADD L"); break;
        case 0x86: printf("ADD M"); break;
        case 0x87: printf("ADD A"); break;

        case 0x88: printf("ADC B"); break;
        case 0x89: printf("ADC C"); break;
        case 0x8a: printf("ADC D"); break;
        case 0x8b: printf("ADC E"); break;
        case 0x8c: printf("ADC H"); break;
        case 0x8d: printf("ADC L"); break;
        case 0x8e: printf("ADC M"); break;
        case 0x8f: printf("ADC A"); break;

        case 0x90: printf("SUB B"); break;
        case 0x91: printf("SUB C"); break;
        case 0x92: printf("SUB D"); break;
        case 0x93: printf("SUB E"); break;
        case 0x94: printf("SUB H"); break;
        case 0x95: printf("SUB L"); break;
        case 0x96: printf("SUB M"); break;
        case 0x97: printf("SUB A"); break;

        case 0x98: printf("SBB B"); break;
        case 0x99: printf("SBB C"); break;
        case 0x9a: printf("SBB D"); break;
        case 0x9b: printf("SBB E"); break;
        case 0x9c: printf("SBB H"); break;
        case 0x9d: printf("SBB L"); break;
        case 0x9e: printf("SBB M"); break;
        case 0x9f: printf("SBB A"); break;

        case 0xa0: printf("ANA B"); break;
        case 0xa1: printf("ANA C"); break;
        case 0xa2: printf("ANA D"); break;
        case 0xa3: printf("ANA E"); break;
        case 0xa4: printf("ANA H"); break;
        case 0xa5: printf("ANA L"); break;
        case 0xa6: printf("ANA M"); break;
        case 0xa7: printf("ANA A"); break;

        case 0xa8: printf("XRA B"); break;
        case 0xa9: printf("XRA C"); break;
        case 0xaa: printf("XRA D"); break;
        case 0xab: printf("XRA E"); break;
        case 0xac: printf("XRA H"); break;
        case 0xad: printf("XRA L"); break;
        case 0xae: printf("XRA M"); break;
        case 0xaf: printf("XRA A"); break;

        case 0xb0: printf("ORA B"); break;
        case 0xb1: printf("ORA C"); break;
        case 0xb2: printf("ORA D"); break;
        case 0xb3: printf("ORA E"); break;
        case 0xb4: printf("ORA H"); break;
        case 0xb5: printf("ORA L"); break;
        case 0xb6: printf("ORA M"); break;
        case 0xb7: printf("ORA A"); break;

        case 0xb8: printf("CMP B"); break;
        case 0xb9: printf("CMP C"); break;
        case 0xba: printf("CMP D"); break;
        case 0xbb: printf("CMP E"); break;
        case 0xbc: printf("CMP H"); break;
        case 0xbd: printf("CMP L"); break;
        case 0xbe: printf("CMP M"); break;
        case 0xbf: printf("CMP A"); break;

        case 0xc0: printf("RNZ"); break;
        case 0xc1: printf("POP B"); break;
        case 0xc2: printf("JNZ $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xc3: printf("JMP $%02x%02x",code[2],code[1]); opbytes = 3; break; 
        case 0xc4: printf("CNZ $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xc5: printf("PUSH B"); break;
        case 0xc6: printf("ADI,#$%02x", code[1]); opbytes = 2; break;
        case 0xc7: printf("RST 0"); break;

        case 0xc8: printf("RZ"); break;
        case 0xc9: printf("RET"); break;
        case 0xca: printf("JZ $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xcb: printf("NOP"); break;
        case 0xcc: printf("CZ $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xcd: printf("CALL $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xce: printf("ACI,#$%02x", code[1]); opbytes = 2; break;
        case 0xcf: printf("RST 1"); break;

        case 0xd0: printf("RNC"); break;
        case 0xd1: printf("POP D"); break;
        case 0xd2: printf("JNC $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xd3: printf("OUT #$%02x", code[1]); opbytes = 2; break;
        case 0xd4: printf("CNC $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xd5: printf("PUSH D"); break;
        case 0xd6: printf("SUI,#$%02x", code[1]); opbytes = 2; break;
        case 0xd7: printf("RST 2"); break;

        case 0xd8: printf("RC"); break;
        case 0xd9: printf("NOP"); break;
        case 0xda: printf("JC $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xdb: printf("IN #$%02x", code[1]); opbytes = 2; break;
        case 0xdc: printf("CC $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xdd: printf("NOP"); break;
        case 0xde: printf("SBI,#$%02x", code[1]); opbytes = 2; break;
        case 0xdf: printf("RST 3"); break;

        case 0xe0: printf("RPO"); break;
        case 0xe1: printf("POP H"); break;
        case 0xe2: printf("JPO $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xe3: printf("XTHL"); break;
        case 0xe4: printf("CPO $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xe5: printf("PUSH H"); break;
        case 0xe6: printf("ANI,#$%02x", code[1]); opbytes = 2; break;
        case 0xe7: printf("RST 4"); break;

        case 0xe8: printf("RPE"); break;
        case 0xe9: printf("PCHL"); break;
        case 0xea: printf("JPE $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xeb: printf("XCHG"); break;
        case 0xec: printf("CPE $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xed: printf("NOP"); break;
        case 0xee: printf("XRI,#$%02x", code[1]); opbytes = 2; break;
        case 0xef: printf("RST 5"); break;

        case 0xf0: printf("RP"); break;
        case 0xf1: printf("POP PSW"); break;
        case 0xf2: printf("JP $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xf3: printf("DI"); break;
        case 0xf4: printf("CP $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xf5: printf("PUSH PSW"); break;
        case 0xf6: printf("ORI,#$%02x", code[1]); opbytes = 2; break;
        case 0xf7: printf("RST 6"); break;

        case 0xf8: printf("RM"); break;
        case 0xf9: printf("SPHL"); break;
        case 0xfa: printf("JM $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xfb: printf("EI"); break;
        case 0xfc: printf("CM $%02x%02x",code[2],code[1]); opbytes = 3; break;
        case 0xfd: printf("NOP"); break;
        case 0xfe: printf("CPI,#$%02x", code[1]); opbytes = 2; break;
        case 0xff: printf("RST 7"); break;

    }
    printf("\n");
    return opbytes;
}

int main (int argc, char** argv)  {
    int pc = 0; //Program Counter

    buffer* buff = read_file(argv);
    if (buff == NULL) {
        printf("Fatal error.\n");
        return 1;
    }
    print_buffer(buff);
    while (pc < 40) {//buff->length) {
        pc += disassemble8080(buff, pc);
    }
    free(buff);
    return 0;

}