mirror of
https://github.com/DavidBuchanan314/6502-emu.git
synced 2024-12-25 22:30:50 +00:00
Added command line args to set initial machine state
* changed debug print to match a validation run found on nesdev.com
This commit is contained in:
Rob McMullen
parent
b9d74c2a85
commit
c5e9cf084e
84
6502-emu.c
84
6502-emu.c
@ -1,5 +1,6 @@
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <termios.h>
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#include <time.h>
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@ -18,14 +19,15 @@ void step_delay()
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nanosleep(&req, &rem);
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}
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void run_cpu()
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void run_cpu(int verbose, int mem_dump)
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{
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int cycles = 0;
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int cycles_per_step = (CPU_FREQ / (ONE_SECOND / STEP_DURATION));
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for (;;) {
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for (cycles %= cycles_per_step; cycles < cycles_per_step;) {
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cycles += step_cpu();
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if (mem_dump) save_memory(NULL);
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cycles += step_cpu(verbose);
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step_uart();
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}
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step_delay(); // remove this for more speed
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@ -48,26 +50,82 @@ void raw_stdin()
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atexit(restore_stdin);
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}
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int hextoint(char *str) {
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int val;
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if (*str == '$') str++;
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val = strtol(str, NULL, 16);
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return val;
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}
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int main(int argc, char *argv[])
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{
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if (argc != 2) {
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printf("Usage: %s file.rom\n", argv[0]);
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printf("The first 16k of \"file.rom\" is loaded into the last 16k of memory.\n");
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int a, x, y, sp, sr, pc;
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int verbose, interactive, mem_dump;
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int opt;
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verbose = 0;
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interactive = 0;
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mem_dump = 0;
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a = 0;
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x = 0;
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y = 0;
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sp = 0;
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sr = 0;
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pc = -RST_VEC; // negative implies indirect
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while ((opt = getopt(argc, argv, "vima:x:y:r:p:s:g:")) != -1) {
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switch (opt) {
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case 'v':
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verbose = 1;
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break;
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case 'i':
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interactive = 1;
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break;
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case 'm':
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mem_dump = 1;
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break;
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case 'a':
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a = hextoint(optarg);
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break;
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case 'x':
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x = hextoint(optarg);
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break;
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case 'y':
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y = hextoint(optarg);
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break;
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case 's':
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sp = hextoint(optarg);
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break;
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case 'p':
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sr = hextoint(optarg);
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break;
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case 'r':
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case 'g':
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pc = hextoint(optarg);
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break;
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default: /* '?' */
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fprintf(stderr, "Usage: %s [-v] [-i] [-a HEX] [-x HEX] [-y HEX] [-s HEX] [-p HEX] [-g|-r ADDR] file.rom\nThe first 16k of \"file.rom\" is loaded into the last 16k of memory.\n",
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argv[0]);
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exit(EXIT_FAILURE);
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}
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}
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if (optind >= argc) {
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fprintf(stderr, "Expected argument after options\n");
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exit(EXIT_FAILURE);
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}
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if (load_rom(argv[optind]) != 0) {
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printf("Error loading \"%s\".\n", argv[optind]);
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return EXIT_FAILURE;
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}
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if (load_rom(argv[1]) != 0) {
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printf("Error loading \"%s\".\n", argv[1]);
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return EXIT_FAILURE;
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}
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raw_stdin(); // allow individual keystrokes to be detected
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if (interactive) raw_stdin(); // allow individual keystrokes to be detected
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init_tables();
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init_uart();
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reset_cpu();
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run_cpu();
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reset_cpu(a, x, y, sp, sr, pc);
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run_cpu(verbose, mem_dump);
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return EXIT_SUCCESS;
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}
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49
6502.c
49
6502.c
@ -833,18 +833,21 @@ void init_tables() // this is only done at runtime to improve code readability.
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instructions[0xFF] = (Instruction) {"???", inst_NOP, IMPL, 1};
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}
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void reset_cpu()
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void reset_cpu(int _a, int _x, int _y, int _sp, int _sr, int _pc)
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{
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A = 0;
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X = 0;
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Y = 0;
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SP = 0xFF;
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A = _a;
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X = _x;
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Y = _y;
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SP = _sp;
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SR.byte = 0;
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SR.byte = _sr;
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SR.bits.interrupt = 1;
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SR.bits.unused = 1;
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memcpy(&PC, &memory[RST_VEC], sizeof(PC));
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if (_pc < 0)
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memcpy(&PC, &memory[-_pc], sizeof(PC));
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else
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PC = _pc;
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}
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int load_rom(char * filename)
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@ -866,24 +869,32 @@ int load_rom(char * filename)
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return 0;
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}
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int step_cpu() // returns cycle count
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int step_cpu(int verbose) // returns cycle count
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{
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inst = instructions[memory[PC]];
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#ifdef DEBUG
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printf("PC=%04X OPCODE=%02X: %s\r\n", PC, memory[PC], inst.mnemonic);
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printf("A=%02X X=%02X Y=%02X SR=%02X SP=%02X\r\n", A, X, Y, SR.byte, SP);
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/* dump memory for analysis (slows down emulation significantly) */
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FILE * fp = fopen("memdump", "w");
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fwrite(&memory, sizeof(memory), 1, fp);
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fclose(fp);
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#endif
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if (verbose) {
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// almost match for NES dump for easier comparison
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printf("%04X ", PC);
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if (lengths[inst.mode] == 3)
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printf("%02X %02X %02X", memory[PC], memory[PC+1], memory[PC+2]);
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else if (lengths[inst.mode] == 2)
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printf("%02X %02X ", memory[PC], memory[PC+1]);
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else
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printf("%02X ", memory[PC]);
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printf(" %-10s A:%02X X:%02X Y:%02X P:%02X SP:%02X CYC:%03d\n", inst.mnemonic, A, X, Y, SR.byte, SP, 0);
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}
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jumping = 0;
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inst.function();
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if (jumping == 0) PC += lengths[inst.mode];
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return inst.cycles;
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}
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void save_memory(char * filename) { // dump memory for analysis (slows down emulation significantly)
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if (filename == NULL) filename = "memdump";
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FILE * fp = fopen(filename, "w");
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fwrite(&memory, sizeof(memory), 1, fp);
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fclose(fp);
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}
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6
6502.h
6
6502.h
@ -65,8 +65,10 @@ Instruction instructions[0x100];
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void init_tables();
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void reset_cpu();
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void reset_cpu(int _a, int _x, int _y, int _sp, int _sr, int _pc);
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int load_rom(char * filename);
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int step_cpu();
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int step_cpu(int verbose);
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void save_memory(char * filename);
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