381 lines
9.0 KiB
C
381 lines
9.0 KiB
C
#include <stdio.h>
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/*
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Copyright (c) 2021 Devine Lu Linvega
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Permission to use, copy, modify, and distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE.
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*/
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#define TRIM 0x0100
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typedef unsigned char Uint8;
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typedef signed char Sint8;
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typedef unsigned short Uint16;
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typedef struct {
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char name[64], items[64][64];
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Uint8 len, refs;
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} Macro;
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typedef struct {
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char name[64];
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Uint8 refs;
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Uint16 addr;
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} Label;
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typedef struct {
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Uint8 data[256 * 256], mlen;
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Uint16 ptr, length, llen;
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Label labels[512];
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Macro macros[256];
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} Program;
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Program p;
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/* clang-format off */
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char ops[][4] = {
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"BRK", "LIT", "NOP", "POP", "DUP", "SWP", "OVR", "ROT",
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"EQU", "NEQ", "GTH", "LTH", "JMP", "JCN", "JSR", "STH",
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"PEK", "POK", "LDR", "STR", "LDA", "STA", "DEI", "DEO",
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"ADD", "SUB", "MUL", "DIV", "AND", "ORA", "EOR", "SFT"
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};
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int scin(char *s, char c) { int i = 0; while(s[i]) if(s[i++] == c) return i - 1; return -1; } /* string char index */
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int scmp(char *a, char *b, int len) { int i = 0; while(a[i] == b[i] && i < len) if(!a[i++]) return 1; return 0; } /* string compare */
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int sihx(char *s) { int i = 0; char c; while((c = s[i++])) if(!(c >= '0' && c <= '9') && !(c >= 'a' && c <= 'f')) return 0; return 1; } /* string is hexadecimal */
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int ssin(char *s, char *ss) { int a = 0, b = 0; while(s[a]) { if(s[a] == ss[b]) { if(!ss[b + 1]) return a - b; b++; } else b = 0; a++; } return -1; } /* string substring index */
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int shex(char *s) { int n = 0, i = 0; char c; while((c = s[i++])) if(c >= '0' && c <= '9') n = n * 16 + (c - '0'); else if(c >= 'a' && c <= 'f') n = n * 16 + 10 + (c - 'a'); return n; } /* string to num */
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int slen(char *s) { int i = 0; while(s[i] && s[++i]) ; return i; } /* string length */
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char *scpy(char *src, char *dst, int len) { int i = 0; while((dst[i] = src[i]) && i < len - 2) i++; dst[i + 1] = '\0'; return dst; } /* string copy */
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char *scat(char *dst, const char *src) { char *ptr = dst + slen(dst); while(*src) *ptr++ = *src++; *ptr = '\0'; return dst; } /* string cat */
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#pragma mark - Helpers
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/* clang-format on */
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#pragma mark - I/O
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void
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pushbyte(Uint8 b, int lit)
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{
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if(lit) pushbyte(0x01, 0);
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p.data[p.ptr++] = b;
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p.length = p.ptr;
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}
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void
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pushshort(Uint16 s, int lit)
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{
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if(lit) pushbyte(0x21, 0);
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pushbyte((s >> 8) & 0xff, 0);
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pushbyte(s & 0xff, 0);
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}
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void
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pushword(char *s)
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{
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int i = 0;
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char c;
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while((c = s[i++])) pushbyte(c, 0);
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}
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Macro *
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findmacro(char *name)
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{
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int i;
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for(i = 0; i < p.mlen; ++i)
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if(scmp(p.macros[i].name, name, 64))
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return &p.macros[i];
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return NULL;
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}
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Label *
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findlabel(char *name)
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{
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int i;
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for(i = 0; i < p.llen; ++i)
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if(scmp(p.labels[i].name, name, 64))
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return &p.labels[i];
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return NULL;
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}
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Uint8
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findopcode(char *s)
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{
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int i;
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for(i = 0; i < 0x20; ++i) {
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int m = 0;
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char *o = ops[i];
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if(o[0] != s[0] || o[1] != s[1] || o[2] != s[2])
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continue;
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while(s[3 + m]) {
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if(s[3 + m] == '2')
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i |= (1 << 5); /* mode: short */
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else if(s[3 + m] == 'r')
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i |= (1 << 6); /* mode: return */
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else
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return 0; /* failed to match */
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m++;
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}
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return i;
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}
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return 0;
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}
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char *
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sublabel(char *src, char *scope, char *name)
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{
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return scat(scat(scpy(scope, src, 64), "/"), name);
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}
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#pragma mark - Parser
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int
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error(char *name, char *id)
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{
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printf("Error: %s[%s]\n", name, id);
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return 0;
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}
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int
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makemacro(char *name, FILE *f)
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{
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Macro *m;
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char word[64];
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if(findmacro(name))
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return error("Macro duplicate", name);
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if(sihx(name) && slen(name) % 2 == 0)
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return error("Macro name is hex number", name);
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if(findopcode(name))
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return error("Macro name is invalid", name);
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m = &p.macros[p.mlen++];
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scpy(name, m->name, 64);
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while(fscanf(f, "%s", word)) {
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if(word[0] == '{') continue;
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if(word[0] == '}') break;
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if(m->len > 64)
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return error("Macro too large", name);
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if(slen(word) >= 64)
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return error("Word too long", name);
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scpy(word, m->items[m->len++], 64);
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}
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printf("New macro: %s, %d items\n", m->name, m->len);
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return 1;
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}
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int
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makelabel(char *name, Uint16 addr)
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{
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Label *l;
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if(findlabel(name))
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return error("Label duplicate", name);
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if(sihx(name) && slen(name) % 2 == 0)
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return error("Label name is hex number", name);
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if(findopcode(name))
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return error("Label name is invalid", name);
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l = &p.labels[p.llen++];
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l->addr = addr;
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l->refs = 0;
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scpy(name, l->name, 64);
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printf("New label: %s, at 0x%04x\n", l->name, l->addr);
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return 1;
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}
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int
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skipblock(char *w, int *cap, char a, char b)
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{
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if(w[0] == b) {
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*cap = 0;
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return 1;
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}
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if(w[0] == a) *cap = 1;
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if(*cap) return 1;
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return 0;
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}
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int
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walktoken(char *w)
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{
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Macro *m;
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if(findopcode(w) || scmp(w, "BRK", 4))
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return 1;
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switch(w[0]) {
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case '[': return 0;
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case ']': return 0;
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case '\'': return 1;
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case '.': return 2; /* zero-page: LIT addr-lb */
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case ',': return 2; /* relative: LIT addr-rel */
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case ':': return 2; /* absolute: addr-hb addr-lb */
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case ';': return 3; /* absolute: LIT addr-hb addr-lb */
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case '$': return shex(w + 1);
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case '#': return slen(w + 1) == 4 ? 3 : 2;
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case '"': return slen(w + 1);
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}
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if((m = findmacro(w))) {
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int i, res = 0;
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for(i = 0; i < m->len; ++i)
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res += walktoken(m->items[i]);
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return res;
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}
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return error("Unknown label in first pass", w);
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}
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int
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parsetoken(char *w)
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{
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Label *l;
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Macro *m;
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if(w[0] == '.' && (l = findlabel(w + 1))) { /* zero-page */
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if(l->addr > 0xff)
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return error("Address is not in zero page", w);
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pushbyte(l->addr, 1);
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return ++l->refs;
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} else if(w[0] == ',' && (l = findlabel(w + 1))) { /* relative */
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int off = l->addr - p.ptr - 3;
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if(off < -126 || off > 126)
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return error("Address is too far", w);
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pushbyte((Sint8)off, 1);
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return ++l->refs;
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} else if(w[0] == ':' && (l = findlabel(w + 1))) { /* raw */
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pushshort(l->addr, 0);
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return ++l->refs;
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} else if(w[0] == ';' && (l = findlabel(w + 1))) { /* absolute */
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pushshort(l->addr, 1);
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return ++l->refs;
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} else if(findopcode(w) || scmp(w, "BRK", 4)) { /* opcode */
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pushbyte(findopcode(w), 0);
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return 1;
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} else if(w[0] == '"') { /* string */
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pushword(w + 1);
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return 1;
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} else if(w[0] == '\'') { /* char */
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pushbyte((Uint8)w[1], 0);
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return 1;
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} else if(w[0] == '#') { /* immediate */
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if(slen(w + 1) == 1)
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pushbyte((Uint8)w[1], 1);
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if(sihx(w + 1) && slen(w + 1) == 2)
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pushbyte(shex(w + 1), 1);
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else if(sihx(w + 1) && slen(w + 1) == 4)
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pushshort(shex(w + 1), 1);
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else
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return 0;
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return 1;
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} else if(sihx(w)) { /* raw */
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if(slen(w) == 2)
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pushbyte(shex(w), 0);
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else if(slen(w) == 4)
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pushshort(shex(w), 0);
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else
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return error("Hex value length is invalid", w);
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return 1;
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} else if((m = findmacro(w))) {
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int i;
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for(i = 0; i < m->len; ++i)
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if(!parsetoken(m->items[i]))
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return 0;
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return ++m->refs;
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}
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return 0;
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}
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int
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pass1(FILE *f)
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{
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int ccmnt = 0;
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Uint16 addr = 0;
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char w[64], scope[64], subw[64];
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printf("Pass 1\n");
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while(fscanf(f, "%s", w) == 1) {
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if(skipblock(w, &ccmnt, '(', ')')) continue;
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if(w[0] == '|') {
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addr = shex(w + 1);
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} else if(w[0] == '%') {
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if(!makemacro(w + 1, f))
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return error("Pass1 failed", w);
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} else if(w[0] == '@') {
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if(!makelabel(w + 1, addr))
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return error("Pass1 failed", w);
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scpy(w + 1, scope, 64);
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} else if(w[0] == '&') {
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if(!makelabel(sublabel(subw, scope, w + 1), addr))
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return error("Pass1 failed", w);
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} else if(sihx(w))
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addr += slen(w) / 2;
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else
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addr += walktoken(w);
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}
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rewind(f);
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return 1;
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}
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int
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pass2(FILE *f)
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{
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int ccmnt = 0, cmacr = 0;
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char w[64], scope[64], subw[64];
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printf("Pass 2\n");
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while(fscanf(f, "%s", w) == 1) {
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if(w[0] == '%') continue;
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if(w[0] == '&') continue;
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if(w[0] == '[') continue;
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if(w[0] == ']') continue;
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if(skipblock(w, &ccmnt, '(', ')')) continue;
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if(skipblock(w, &cmacr, '{', '}')) continue;
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if(w[0] == '|') {
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if(p.length && shex(w + 1) < p.ptr)
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return error("Memory Overwrite", w);
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p.ptr = shex(w + 1);
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continue;
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} else if(w[0] == '$') {
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p.ptr += shex(w + 1);
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continue;
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} else if(w[0] == '@') {
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scpy(w + 1, scope, 64);
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continue;
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}
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if(w[1] == '&')
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scpy(sublabel(subw, scope, w + 2), w + 1, 64);
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if(!parsetoken(w))
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return error("Unknown label in second pass", w);
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}
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return 1;
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}
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void
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cleanup(char *filename)
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{
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int i;
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printf("Assembled %s(%d bytes), %d labels, %d macros.\n\n", filename, (p.length - TRIM), p.llen, p.mlen);
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for(i = 0; i < p.llen; ++i)
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if(p.labels[i].name[0] >= 'A' && p.labels[i].name[0] <= 'Z')
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continue; /* Ignore capitalized labels(devices) */
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else if(!p.labels[i].refs)
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printf("--- Unused label: %s\n", p.labels[i].name);
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for(i = 0; i < p.mlen; ++i)
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if(!p.macros[i].refs)
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printf("--- Unused macro: %s\n", p.macros[i].name);
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}
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int
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main(int argc, char *argv[])
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{
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FILE *f;
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if(argc < 3)
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return !error("Input", "Missing");
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if(!(f = fopen(argv[1], "r")))
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return !error("Open", "Failed");
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if(!pass1(f) || !pass2(f))
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return !error("Assembly", "Failed");
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fwrite(p.data + TRIM, p.length - TRIM, 1, fopen(argv[2], "wb"));
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fclose(f);
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cleanup(argv[2]);
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return 0;
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}
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