ref: bd868e6e88690ee8521e3c3738f908b6557a1ac1
dir: /as/main.c/
#include <ctype.h> #include <stdarg.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include "../inc/scc.h" #include "as.h" #define MAXLINE 100 #define NARGS 20 int nerrors; void error(char *msg, ...) { va_list va; va_start(va, msg); fputs("as: ", stderr); vfprintf(stderr, msg, va); putc('\n', stderr); nerrors++; va_end(va); } int cmp(const void *f1, const void *f2) { const Ins *ins = f2; return strcmp(f1, ins->str); } int match(Op *op, Arg *args) { return 1; } Arg number(char *s, int base) { Arg arg; TUINT n; /* TODO: Check overflow here */ arg.type = AIMM; for (n = 0; *s; n += *s++ - '0') n *= base; arg.val = n; return arg; } Arg * getargs(char *s) { char *t; int ch, len; Arg *ap; static Arg args[NARGS]; for (ap = args; s; ++ap) { while (isspace(*s)) ++s; if (*s == '\0') break; if (ap == &args[NARGS-1]) die("too many arguments in one instruction"); for (t = s; *s && *s != ','; s++) /* nothing */; len = t - s; if (len == 0) goto wrong_operand; if (*s) *s++ = '\0'; ch = *t; if (isdigit(ch)) { *ap = number(t, (s[len-1] == 'H') ? 16 : 10); continue; } wrong_operand: error("wrong operand '%s'", t); } ap->type = 0; return args; } void incpc(int siz) { TUINT pc, curpc; pc = cursec->pc; curpc = cursec->curpc; cursec->curpc += siz; cursec->pc += siz; if (pass == 2) return; if (cursec->pc > cursec->max) cursec->max = cursec->pc; if (pc > cursec->pc || curpc > cursec->curpc || cursec->curpc > maxaddr || cursec->pc > maxaddr) { die("address overflow"); } } void as(char *text, char *xargs) { Ins *ins; Op *op, *lim; Arg *args; ins = bsearch(text, instab, nr_ins, sizeof(Ins), cmp); if (!ins) { error("invalid instruction"); return; } args = getargs(xargs); lim = &optab[ins->end]; for (op = &optab[ins->begin]; op < lim; ++op) { if (match(op, args)) break; } if (op == lim) { error("invalid operands"); return; } (*op->format)(op, args); } int extract(char *p, char **lbl, char **ins, char **args) { *lbl = p; *ins = NULL; *args = NULL; if ((p = strchr(p, '\t')) == NULL) return 0; *p++ = '\0'; *ins = p; if ((p = strchr(p, '\t')) == NULL) return 1; *p++ = '\0'; *args = p; if ((p = strchr(p, '\t')) == NULL) return 2; *p = '\0'; return 3; } int dopass(char *file) { FILE *in; char line[MAXLINE], *ins, *lbl, *args; if ((in = fopen(file, "r")) == NULL) die("error opening '%s'", file); isections(); while (fgets(line, sizeof(line), in)) { size_t n = strlen(line); if (n == 0 || line[0] == ';') continue; if (line[n-1] != '\n') { error("line too long"); continue; } line[n-1] = '\0'; if (extract(line, &lbl, &ins, &args) > 0) as(ins, args); } if (fclose(in)) die("error reading from input file"); return nerrors == 0; } static void usage(void) { fputs("usage: as filename\n", stderr); exit(1); } int main(int argc, char *argv[]) { if (argc != 2) usage(); for (pass = 1; pass <= 2 && dopass(argv[1]); pass++) /* nothing */; writeout("a.out"); return 0; }