c_cpp/etc/calc/endian.c

   1 /*
   2  * endian - determine the byte order of a long on your machine
   3  *
   4  * Copyright (C) 1999-2013  Landon Curt Noll
   5  *
   6  * Calc is open software; you can redistribute it and/or modify it under
   7  * the terms of the version 2.1 of the GNU Lesser General Public License
   8  * as published by the Free Software Foundation.
   9  *
  10  * Calc is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
  13  * Public License for more details.
  14  *
  15  * A copy of version 2.1 of the GNU Lesser General Public License is
  16  * distributed with calc under the filename COPYING-LGPL.  You should have
  17  * received a copy with calc; if not, write to Free Software Foundation, Inc.
  18  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19  *
  20  * @(#) $Revision: 30.4 $
  21  * @(#) $Id: endian.c,v 30.4 2013/05/05 13:57:08 chongo Exp $
  22  * @(#) $Source: /usr/local/src/bin/calc/RCS/endian.c,v $
  23  *
  24  * Under source code control:   1993/11/15 04:32:58
  25  * File existed as early as:    1993
  26  *
  27  * chongo <was here> /\oo/\     http://www.isthe.com/chongo/
  28  * Share and enjoy!  :-)        http://www.isthe.com/chongo/tech/comp/calc/
  29  */
  30
  31 /*
  32  * Big Endian:      Amdahl, 68k, Pyramid, Mips, Sparc, ...
  33  * Little Endian:   Vax, 32k, Spim (Dec Mips), i386, i486, ...
  34  */
  35
  36
  37 #include <stdio.h>
  38
  39 #include "have_stdlib.h"
  40 #if defined(HAVE_STDLIB_H)
  41 #include <stdlib.h>
  42 #endif
  43
  44 #include "have_unistd.h"
  45 #if defined(HAVE_UNISTD_H)
  46 #include <unistd.h>
  47 #endif
  48
  49 /* byte order array */
  50 char byte[8] = { (char)0x12, (char)0x36, (char)0x48, (char)0x59,
  51                  (char)0x01, (char)0x23, (char)0x45, (char)0x67 };
  52
  53 int
  54 main(void)
  55 {
  56         /* pointers into the byte order array */
  57 #if defined(DEBUG) || (!defined(BIG_ENDIAN) && !defined(BIG_ENDIAN))
  58         int *intp = (int *)byte;
  59 #endif
  60 #if defined(DEBUG)
  61         short *shortp = (short *)byte;
  62         long *longp = (long *)byte;
  63
  64         printf("byte: %02x %02x %02x %02x %02x %02x %02x %02x\n",
  65             byte[0], byte[1], byte[2], byte[3],
  66             byte[4], byte[5], byte[6], byte[7]);
  67         printf("short: %04x %04x %04x %04x\n",
  68             shortp[0], shortp[1], shortp[2], shortp[3]);
  69         printf("int: %08x %08x\n",
  70             intp[0], intp[1]);
  71         printf("long: %08x %08x\n",
  72             longp[0], longp[1]);
  73 #endif
  74
  75         /* Print the standard <machine/endian.h> defines */
  76         printf("#undef BIG_ENDIAN\n");
  77         printf("#define BIG_ENDIAN\t4321\n");
  78         printf("#undef LITTLE_ENDIAN\n");
  79         printf("#define LITTLE_ENDIAN\t1234\n");
  80         printf("#undef CALC_BYTE_ORDER\n");
  81
  82 #if defined(BIG_ENDIAN)
  83         printf("#define CALC_BYTE_ORDER\tBIG_ENDIAN\n");
  84 #elif defined(LITTLE_ENDIAN)
  85         printf("#define CALC_BYTE_ORDER\tLITTLW_ENDIAN\n");
  86 #else
  87         /* Determine byte order */
  88         if (intp[0] == 0x12364859) {
  89             /* Most Significant Byte first */
  90             printf("#define CALC_BYTE_ORDER\tBIG_ENDIAN\n");
  91         } else if (intp[0] == 0x59483612) {
  92             /* Least Significant Byte first */
  93             printf("#define CALC_BYTE_ORDER\tLITTLE_ENDIAN\n");
  94         } else {
  95             fprintf(stderr, "@=-=@ Fatal build error - cannot @=-=@\n");
  96             fprintf(stderr, "@=-=@ determine byte order.  Set @=-=@\n");
  97             fprintf(stderr, "@=-=@ ${CALC_BYTE_ORDER} in the Makefile @=-=@\n");
  98             fprintf(stderr, "@=-=@ to be either -DBIG_ENDIAN or @=-=@\n");
  99             fprintf(stderr, "@=-=@ to be -DLITTLE_ENDIAN @=-=@\n");
 100             exit(1);
 101         }
 102 #endif
 103         /* exit(0); */
 104         return 0;
 105 }