348 lines
9.0 KiB
C
348 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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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 signed short Sint16;
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typedef struct
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{
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char name[64];
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unsigned int size;
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} Map;
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typedef struct {
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char name[64];
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Uint8 len, offset, refs;
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Uint16 addr;
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/* map */
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Map map[16];
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Uint8 maps;
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} Label;
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typedef struct {
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Uint8 data[256 * 256], tlen, llen;
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Uint16 ptr;
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Label labels[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", "NOP", "LIT", "JMP", "JSR", "RTS", "LDR", "STR",
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"---", "---", "---", "---", "AND", "XOR", "ROL", "ROR",
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"POP", "DUP", "SWP", "OVR", "ROT", "---", "WSR", "RSW",
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"ADD", "SUB", "MUL", "DIV", "EQU", "NEQ", "GTH", "LTH"
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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 slen(char *s) { int i = 0; while(s[i] && s[++i]) ; return i; } /* string length */
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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') && !(c >= 'A' && c <= 'F')) return 0; return 1; } /* string is hexadecimal */
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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'); else if(c >= 'a' && c <= 'f') n = n * 16 + 10 + (c - 'a'); return n; } /* string to num */
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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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#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(0x02, 0);
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p.data[p.ptr++] = b;
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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(0x22, 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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pushtext(char *s, int lit)
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{
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int i = 0;
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char c;
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if(lit) pushbyte(0x22, 0);
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while((c = s[i++])) pushbyte(c, 0);
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}
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Label *
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findlabel(char *s)
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{
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int i, rng = scin(s, '.');
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char name[64];
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scpy(s, name, rng > 0 ? rng + 1 : 64);
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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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Uint16
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findlabeladdr(char *s)
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{
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int i, o = 0;
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char *param;
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Label *l = findlabel(s);
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if(scin(s, '.') < 1)
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return l->addr;
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param = s + scin(s, '.') + 1;
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for(i = 0; i < l->maps; ++i) {
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if(scmp(l->map[i].name, param, 64))
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return l->addr + o;
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o += l->map[i].size;
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}
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printf("!!! Warning %s.%s\n", l->name, param);
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return 0;
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}
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Uint8
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findlabellen(char *s)
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{
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int i;
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char *param;
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Label *l = findlabel(s);
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if(scin(s, '.') < 1)
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return l->len;
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param = s + scin(s, '.') + 1;
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for(i = 0; i < l->maps; ++i)
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if(scmp(l->map[i].name, param, 64))
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return l->map[i].size;
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printf("!!! Warning %s.%s\n", l->name, param);
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return 0;
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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') i |= (1 << 5); /* mode: short */
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if(s[3 + m] == 'S') i |= (1 << 6); /* mode: signed */
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if(s[3 + m] == '?') i |= (1 << 7); /* mode: conditional */
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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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scpy(scope, src, 64);
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scpy("-", src + slen(src), 64);
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scpy(name, src + slen(src), 64);
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return src;
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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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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[%d]\n", l->name, l->addr, l->len);
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return 1;
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}
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int
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makevariable(char *name, Uint16 *addr, FILE *f)
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{
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Label *l;
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char word[64];
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if(!makelabel(name, *addr))
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return error("Could not create variable", name);
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l = findlabel(name);
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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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scpy(word, l->map[l->maps].name, 64);
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fscanf(f, "%u", &l->map[l->maps].size);
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*addr += l->map[l->maps].size;
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l->maps++;
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}
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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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pass1(FILE *f)
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{
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int ccmnt = 0, cbits = 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(skipblock(w, &cbits, '[', ']')) {
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if(w[0] == '[' || w[0] == ']')
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continue;
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if(sihx(w))
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addr += slen(w) == 4 ? 2 : 1;
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else
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addr += slen(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(w[0] == ';') {
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if(!makevariable(w + 1, &addr, f))
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return error("Pass1 failed", w);
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} else if(findopcode(w) || scmp(w, "BRK", 4))
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addr += 1;
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else {
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switch(w[0]) {
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case '|':
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if(shex(w + 1) < addr)
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return error("Memory Overlap", w);
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addr = shex(w + 1);
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break;
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case '=': addr += 4; break; /* STR helper (lit addr-hb addr-lb str) */
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case '~': addr += 4; break; /* LDR helper (lit addr-hb addr-lb ldr) */
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case ',': addr += 3; break;
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case '.': addr += 2; break;
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case '^': addr += 2; break; /* Relative jump: lit addr-offset */
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case '+': /* signed positive */
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case '-': /* signed negative */
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case '#': addr += (slen(w + 1) == 2 ? 2 : 3); break;
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default: return error("Unknown label in first pass", w);
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}
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}
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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, cbits = 0, ctemplate = 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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Uint8 op = 0;
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Label *l;
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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, &ctemplate, '{', '}')) continue;
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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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sublabel(subw, scope, w + 2);
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scpy(subw, w + 1, 64);
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}
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/* clang-format off */
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if(skipblock(w, &cbits, '[', ']')) {
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if(w[0] == '[' || w[0] == ']') { continue; }
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if(slen(w) == 4 && sihx(w)) pushshort(shex(w), 0);
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else if(slen(w) == 2 && sihx(w)) pushbyte(shex(w), 0);
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else pushtext(w, 0);
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}
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else if(w[0] == '^' && (l = findlabel(w + 1))) {
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int off = l->addr - p.ptr - 3;
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if(off < -126 || off > 126){ printf("Address %s is too far(%d).\n", w, off); return 0; }
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pushbyte((Sint8)(l->addr - p.ptr - 3), 1); l->refs++;
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}
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else if(w[0] == '|') p.ptr = shex(w + 1);
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else if((op = findopcode(w)) || scmp(w, "BRK", 4)) pushbyte(op, 0);
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else if(w[0] == '.' && (l = findlabel(w + 1))) { pushshort(findlabeladdr(w + 1), 0); l->refs++; }
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else if(w[0] == ',' && (l = findlabel(w + 1))) { pushshort(findlabeladdr(w + 1), 1); l->refs++; }
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else if(w[0] == '=' && (l = findlabel(w + 1))) { pushshort(findlabeladdr(w + 1), 1); pushbyte(findopcode(findlabellen(w + 1) == 2 ? "STR2" : "STR"), 0); l->refs++;}
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else if(w[0] == '~' && (l = findlabel(w + 1))) { pushshort(findlabeladdr(w + 1), 1); pushbyte(findopcode(findlabellen(w + 1) == 2 ? "LDR2" : "LDR"), 0); l->refs++;}
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else if(w[0] == '#' && sihx(w + 1) && slen(w + 1) == 2) pushbyte(shex(w + 1), 1);
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else if(w[0] == '#' && sihx(w + 1) && slen(w + 1) == 4) pushshort(shex(w + 1), 1);
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else if(w[0] == '+' && sihx(w + 1) && slen(w + 1) == 2) pushbyte((Sint8)shex(w + 1), 1);
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else if(w[0] == '+' && sihx(w + 1) && slen(w + 1) == 4) pushshort((Sint16)shex(w + 1), 1);
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else if(w[0] == '-' && sihx(w + 1) && slen(w + 1) == 2) pushbyte((Sint8)(shex(w + 1) * -1), 1);
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else if(w[0] == '-' && sihx(w + 1) && slen(w + 1) == 4) pushshort((Sint16)(shex(w + 1) * -1), 1);
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else return error("Unknown label in second pass", w);
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/* clang-format on */
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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.\n\n", filename);
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for(i = 0; i < p.llen; ++i)
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if(!p.labels[i].refs)
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printf("--- Unused label: %s\n", p.labels[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, sizeof(p.data), 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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