mirror of https://git.sr.ht/~rabbits/uxn
298 lines
7.2 KiB
C
298 lines
7.2 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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int ptr;
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Uint8 data[65536];
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} Program;
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typedef struct {
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Uint8 len;
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Uint16 addr;
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char name[64];
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} Label;
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int labelslen;
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Label labels[256];
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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", "---", "IOR", "IOW", "LDR", "STR",
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"JMP", "JSR", "---", "RTS", "AND", "ORA", "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 scmp(char *a, char *b) { int i = 0; while(a[i] == b[i]) 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)
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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)
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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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Label *
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findlabel(char *s)
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{
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int i;
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for(i = 0; i < labelslen; ++i)
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if(scmp(labels[i].name, s))
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return &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') 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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#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, Uint8 len)
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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))
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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 = &labels[labelslen++];
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l->addr = addr;
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l->len = len;
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scpy(name, l->name, 64);
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printf("New label: %s, at 0x%02x[%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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makeconst(char *id, FILE *f)
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{
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char wv[64];
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fscanf(f, "%s", wv);
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return makelabel(id, shex(wv), 1);
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}
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int
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makevariable(char *id, Uint16 *addr, FILE *f)
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{
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char wv[64];
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Uint8 origin;
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fscanf(f, "%s", wv);
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if(!sihx(wv))
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return error("Variable value is invalid", wv);
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origin = *addr;
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*addr += shex(wv);
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return makelabel(id, origin, shex(wv));
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}
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int
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skipcomment(char *w, int *cap)
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{
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if(w[0] == ')') {
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*cap = 0;
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return 1;
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}
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if(w[0] == '(') *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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skipbinary(char *w, int *cap)
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{
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if(w[0] == ']') {
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*cap = 0;
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return 1;
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}
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if(w[0] == '[') *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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skipstring(char *w, int *cap, Uint16 *addr)
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{
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if(w[0] == '"') {
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if(*cap)
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*addr += 1;
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*cap = !(*cap);
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return 1;
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}
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if(*cap) {
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*addr += slen(w) + 1;
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return 1;
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}
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return 0;
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}
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int
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capturestring(char *w, int *cap)
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{
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if(w[0] == '"') {
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if(*cap)
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pushbyte(0x00, 0);
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*cap = !(*cap);
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return 1;
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}
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if(*cap) {
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int i;
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for(i = 0; i < slen(w); ++i)
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pushbyte(w[i], 0);
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pushbyte(' ', 0);
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return 1;
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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, cstrg = 0, cbits = 0;
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Uint16 addr = 0;
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char w[64];
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while(fscanf(f, "%s", w) == 1) {
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if(skipcomment(w, &ccmnt)) continue;
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if(skipstring(w, &cstrg, &addr)) continue;
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if(skipbinary(w, &cbits))
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addr += w[0] != '[' && w[0] != ']' ? 2 : 0;
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else if(w[0] == '@') {
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if(!makelabel(w + 1, addr, 0))
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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(w[0] == ':') {
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if(!makeconst(w + 1, f))
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return error("Pass1 failed", w);
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} else if(findopcode(w) || scmp(w, "BRK"))
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addr += 1;
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else {
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switch(w[0]) {
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case '|': addr = shex(w + 1); break;
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case '=': addr += 4; break; /* STR helper */
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case '~': addr += 4; break; /* LDR helper */
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case ',': addr += 3; break;
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case '.': addr += (slen(w + 1) == 2 ? 1 : 2); break;
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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, cstrg = 0, cbits = 0;
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char w[64];
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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(skipcomment(w, &ccmnt)) continue;
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if(capturestring(w, &cstrg)) continue;
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/* clang-format off */
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if(skipbinary(w, &cbits)) { if(w[0] != '[' && w[0] != ']') { pushshort(shex(w), 0); } }
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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")) pushbyte(op, 0);
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else if(w[0] == ':') fscanf(f, "%s", w);
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else if(w[0] == ';') fscanf(f, "%s", w);
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else if(w[0] == '.' && sihx(w + 1) && slen(w + 1) == 2) pushbyte(shex(w + 1), 0);
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else if(w[0] == '.' && sihx(w + 1) && slen(w + 1) == 4) pushshort(shex(w + 1), 0);
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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 if(w[0] == '=' && (l = findlabel(w + 1)) && l->len){ pushshort(l->addr, 1); pushbyte(findopcode(l->len == 2 ? "STR2" : "STR"),0); }
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else if(w[0] == '~' && (l = findlabel(w + 1)) && l->len){ pushshort(l->addr, 1); pushbyte(findopcode(l->len == 2 ? "LDR2" : "LDR"),0); }
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else if((l = findlabel(w + 1))) pushshort(l->addr, w[0] == ',');
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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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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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printf("Assembled %s.\n\n", argv[2]);
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return 0;
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}
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