int emu_step() {
instruction in;
int i;
char *state;
int result;
in.instr = read_insrtuction(memory.R[7]);
memset(disas, '0', LEN);
memset(reg, '0', LEN);
for (i = 0; i < COUNT; i++) {
if (check_instr(i, in)) {
sprintf(disas, "%06o %s", in.instr, table[i].assembler(in));
result = handle_callback(i, in);
switch(result) {
case EX:
state = "Execution";
break;
case HLT:
state = "Completed";
break;
default:
state = "Unknown error";
}
set_reg(state);
return in.instr;
}
}
sprintf(disas, "%s", "UNKNOWN COMMAND");
set_reg("ERROR UNKNOWN OPCODE");
return UNKNOWN_COMMAND;
}
int
main(int argc, char **argv)
{
const char *filename;
int i;
/* Process command line */
if (argc < 2) {
usage();
exit(EXIT_FAILURE);
}
for (i = 1; i < argc - 1; i++)
if (streq(argv[i],"-i"))
print_instrs = TRUE;
else if (streq(argv[i],"-q"))
quiet = TRUE;
else if (streq(argv[i],"-s"))
statistics = TRUE;
else
usage();
filename = argv[argc-1];
ozyyin = fopen(filename, "r");
ozyyfile = filename;
ozyylinenum = 1;
if (ozyyin == NULL) {
perror(filename);
exit(EXIT_FAILURE);
}
if (ozyyparse() != 0) {
/* the error message will already have been printed */
exit(EXIT_FAILURE);
}
init_all_regs();
init_stack();
pc = 0;
cur_instr = 0;
while (! halted && ! found_error) {
if (! check_instr(pc))
report_error_and_exit("execution fell out of the program");
next_pc = pc + 1;
execute_instr_at_pc();
cur_instr++;
pc = next_pc;
}
if (found_error)
exit(EXIT_FAILURE);
if (statistics) {
printf("Number of instructions in program code: %d.\n", next_instr);
printf("Number of instructions executed: %d.\n", cur_instr);
}
return 0;
}
