hwvm.c

   1 #include "vm.h"
   2
   3 #include <stdarg.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6
   7 static void start_vm(FILE *, const HwHeader *);
   8 static void execute_opcode(uint8_t);
   9 static void vm_error(const char *, ...);
  10
  11 int
  12 main(int argc, char **argv)
  13 {
  14     FILE *file;
  15     HwHeader head;
  16
  17     if (argc == 1)
  18        vm_error("No executable file!\n");
  19
  20     file = fopen(argv[1], "rt");
  21     if (file == NULL)
  22        vm_error("Cannot read file %s\n", argv[1]);
  23
  24     fread(&head, sizeof(HwHeader), 1, file);
  25
  26     if (head.hw_magic != HW_HEADER_MAGIC)
  27         vm_error("File is corrupted or not a valid application!\n");
  28
  29     start_vm(file, &head);
  30     return 0;
  31 }
  32
  33 static void
  34 start_vm(FILE *file, const HwHeader *head)
  35 {
  36     uint8_t *text_segment;
  37     int i;
  38     text_segment = (uint8_t *)malloc(sizeof(uint8_t) * head->hw_instr_count);
  39
  40     if (text_segment == NULL)
  41         vm_error("Cannot allocate text segment\n");
  42
  43     fread(text_segment, sizeof(uint8_t), head->hw_instr_count, file);
  44
  45     for (i = 0; i < head->hw_instr_count; i++) {
  46         execute_opcode(text_segment[i]);
  47     }
  48
  49 }
  50 static void
  51 execute_opcode(uint8_t opcode)
  52 {
  53     HwInstruction *inst;
  54     int i;
  55
  56     for (i = 0; i < LAST_INSTRUCTION; i++) {
  57         inst = &instructions[i];
  58         if (opcode == inst->i_opcode) {
  59             printf("%s", inst->i_data);
  60         }
  61     }
  62 }
  63
  64 static void
  65 vm_error(const char *fmt, ...)
  66 {
  67     va_list ap;
  68     va_start(ap, fmt);
  69     fprintf(stderr, "HW Virtual Machine - (C) Akos Kovacs\n\nError: ");
  70     vfprintf(stderr, fmt, ap);
  71     va_end(ap);
  72     exit(1);
  73 }