ngaro/c-crc/sdl/endian.c

   1 /******************************************************
   2  * Ngaro
   3  *
   4  *|F|
   5  *|F| FILE: endian.c
   6  *|F|
   7  *
   8  * Written by Charles Childers, released into the public
   9  * domain
  10  ******************************************************/
  11
  12 #include <stdio.h>
  13 #include <stddef.h>
  14 #include <stdlib.h>
  15
  16 #include "functions.h"
  17 #include "vm.h"
  18
  19 extern VM_STATE vm;
  20
  21 #define BIGENDIAN     0
  22 #define LITTLEENDIAN  1
  23
  24 /* This is a slightly tricky bit of code to convert an image from one endian to the other. */
  25 /* It's only recieved minimal testing, so I hope it actually works... */
  26 void swapEndian()
  27 {
  28   int endian, x, a;
  29   short int word = 0x0001;
  30   char *byte = (char *) &word;
  31   endian = (byte[0] ? LITTLEENDIAN : BIGENDIAN);
  32
  33   if (endian == LITTLEENDIAN)
  34     printf("Converting to big endian\n");
  35   if (endian == BIGENDIAN)
  36     printf("Converting to little endian\n");
  37
  38   for(a = 0; a < IMAGE_SIZE; a++)
  39   {
  40     x = vm.image[a];
  41     vm.image[a] = (x>>24) | ((x<<8) & 0x00FF0000) | ((x>>8) & 0x0000FF00) | (x<<24);
  42   }
  43   printf("Done!\n");
  44 }
  45