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#include "ops.h"
#include "drain.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
typedef struct Label Label;
struct Label {
const char *s;
size_t addr;
Label *next;
};
static const int hextable[256] = {
['0'] = 0x0, ['1'] = 0x1, ['2'] = 0x2, ['3'] = 0x3, ['4'] = 0x4,
['5'] = 0x5, ['6'] = 0x6, ['7'] = 0x7, ['8'] = 0x8, ['9'] = 0x9,
['a'] = 0xa, ['b'] = 0xb, ['c'] = 0xc, ['d'] = 0xd, ['e'] = 0xe,
['f'] = 0xf,
};
static const char *sep = "\t\n\v\f\r ";
static int verbose = 0;
static char *data = NULL, *data_dup = NULL;
FILE *outfile = NULL;
static Label *label_root = NULL;
static int
fail(void)
{
if (data != NULL)
free(data);
if (data_dup != NULL)
free(data_dup);
while (label_root != NULL) {
Label *const next = label_root->next;
free(label_root);
label_root = next;
}
if (outfile != NULL)
fclose(outfile);
return 1;
}
static void
skip_comments(void)
{
char *tok;
do
tok = strtok(NULL, sep);
while (tok != NULL && strcmp(tok, ")") != 0);
if (tok == NULL) {
fprintf(stderr, "unclosed comment");
exit(fail());
}
}
static void
write_short(uint_least16_t v)
{
if (verbose) printf("write: %04x\n", v);
if (fputc(v & 0x00ff, outfile) == EOF ||
fputc(v / 0x0100, outfile) == EOF) {
fprintf(stderr, "fputc failed\n");
exit(fail());
}
}
static void
register_label(const char *s, size_t pc)
{
Label *const label = malloc(sizeof(Label));
if (label == NULL) {
perror("register_label:malloc");
exit(fail());
}
label->s = s;
label->addr = pc;
label->next = label_root;
label_root = label;
if (verbose) printf("label: '%s' at pc %zu\n", s, pc);
}
static void
write_label(const char *s)
{
for (Label *label = label_root; label != NULL; label = label->next) {
if (strcmp(s, label->s) == 0) {
write_short(label->addr);
return;
}
}
fprintf(stderr, "unknown label '%s'\n", s);
}
static int
opcmp(const char *s0, const char *s1)
{
return (s0[0] == s1[0] && s0[1] == s1[1] && s0[2] == s1[2]);
}
static void
write_opcode(const char *s)
{
for (unsigned i = 0; i < sizeof(ops) / sizeof(ops[0]); i++) {
if (opcmp(s, ops[i])) {
write_short(i);
return;
}
}
fprintf(stderr, "unknown opcode '%s'\n", s);
exit(fail());
}
static int
ishex(int c)
{
return ((c >= 'a' && c <= 'f') || (c >= '0' && c <= '9'));
}
static void
write_literal(const char *s)
{
if (!ishex(s[0]) && !ishex(s[1]) && !ishex(s[2]) && !ishex(s[3])) {
fprintf(stderr, "invalid literal '%s'\n", s);
exit(fail());
}
write_short((hextable[(int)s[0]] * 0x1000) |
(hextable[(int)s[1]] * 0x100) |
(hextable[(int)s[2]] * 0x10) |
(hextable[(int)s[3]]));
}
static void
first_pass(char *s)
{
char *tok;
size_t pc = 0;
for (tok = strtok(s, sep); tok != NULL; tok = strtok(NULL, sep)) {
/* Skip comment. */
if (strcmp(tok, "(") == 0) {
skip_comments();
continue;
}
/* Label marker. */
if (tok[0] == '@')
register_label(tok + 1, pc);
else
pc += 1;
}
}
static void
second_pass(char *s)
{
char *tok;
for (tok = strtok(s, sep); tok != NULL; tok = strtok(NULL, sep)) {
switch (tok[0]) {
case '@': /* label declaration, skip */
continue;
case ',': /* label insertion */
write_label(tok + 1);
continue;
default:
break;
}
/* Skip comment. */
if (strcmp(tok, "(") == 0) {
skip_comments();
continue;
}
const size_t tok_len = strlen(tok);
switch (tok_len) {
case 3: /* opcode */
if (verbose) printf("opcode: %s\n", tok);
write_opcode(tok);
break;
case 4: /* literal */
if (verbose) printf("literal: %s\n", tok);
write_literal(tok);
break;
default: /* wtf */
fprintf(stderr, "unknown token '%s'\n", tok);
exit(fail());
}
}
}
int
main(int argc, char **argv)
{
if (!(argc == 3 || (argc == 4 && strcmp(argv[3], "-v") == 0))) {
fprintf(stderr, "usage: %s <asm> <rom> [-v]\n", argv[0]);
return fail();
}
verbose = (argc == 4);
/* Dump file to memory. */
FILE *const fp = fopen(argv[1], "rb");
if (fp == NULL) {
perror(argv[1]);
return fail();
}
long size;
data = drain(fp, &size);
fclose(fp);
if (data == NULL)
return fail();
/* Duplicate data. */
data_dup = malloc(strlen(data) + 1);
if (data_dup == NULL) {
perror("main:malloc");
return fail();
}
strcpy(data_dup, data);
/* First pass, find labels. */
first_pass(data);
/* Open out file. */
outfile = fopen(argv[2], "wb");
if (outfile == NULL) {
perror(argv[2]);
return fail();
}
/* Second pass, generate bytecode. */
second_pass(data_dup);
return fail(), 0;
}
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