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/* @(#)endian.c 12.1 17 Nov 1995 04:22:20 */
/*
* endian - Determine the byte order of a long on your machine.
*
* Big Endian: Amdahl, 68k, Pyramid, Mips, Sparc, ...
* Little Endian: Vax, 32k, Spim (Dec Mips), i386, i486, ...
*
* This makefile was written by:
*
* Landon Curt Noll (chongo@toad.com) chongo <was here> /\../\
*
* This code has been placed in the public domain. Please do not
* copyright this code.
*
* LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO
* THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MER-
* CHANTABILITY AND FITNESS. IN NO EVENT SHALL LANDON CURT
* NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* See shsdrvr.c and md5drvr.c for version and modification history.
*
* Modified by Clayton O'Neill <coneill@oneill.net> to determine
* endianness and if longs must be aligned.
*/
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
/*#include <configdata.h>*/
/*#include <clibrary.h>*/
/*
* buserr - catch an alignment error
*/
void buserr(int dummy)
{
/* alignment is required */
printf("#define MUST_ALIGN\n");
exit(0);
}
/*
* some compiler recognize the code unwantedly
* to avoid this the code is separated and call store() and load_and_store()
*/
void
store(unsigned long *p, unsigned long val)
{
*p = val;
}
void
load_and_store(unsigned long *p, unsigned long val)
{
*p += val;
}
/* byte order array */
char byte[8] = { (char)0x12, (char)0x36, (char)0x48, (char)0x59,
(char)0x01, (char)0x23, (char)0x45, (char)0x67 };
int main()
{
/* pointers into the byte order array */
int *intp = (int *)byte;
char byte[2*sizeof(unsigned long)]; /* mis-alignment buffer */
unsigned long *p; /* mis-alignment pointer */
int i;
/* Print the standard <machine/endian.h> defines */
/* printf("#define BIG_ENDIAN\t4321\n"); */
/* printf("#define LITTLE_ENDIAN\t1234\n"); */
printf("#undef LITTLE_ENDIAN\n");
printf("#undef BIG_ENDIAN\n");
/* Determine byte order */
if (intp[0] == 0x12364859) {
/* Most Significant Byte first */
/* printf("#define BYTE_ORDER\tBIG_ENDIAN\n"); */
printf("#define BIG_ENDIAN\n");
} else if (intp[0] == 0x59483612) {
/* Least Significant Byte first */
/* printf("#define BYTE_ORDER\tLITTLE_ENDIAN\n"); */
printf("#define LITTLE_ENDIAN\n");
} else {
fprintf(stderr, "Unknown int Byte Order, set BYTE_ORDER in Makefile\n");
exit(1);
}
#if !defined(MUST_ALIGN) && !defined(__alpha__) && !defined(__alpha)
/* setup to catch alignment bus errors */
signal(SIGBUS, buserr);
signal(SIGSEGV, buserr); /* some systems will generate SEGV instead! */
/* mis-align our long fetches */
for (i=0; i < sizeof(long); ++i) {
p = (unsigned long *)(byte+i);
store(p, i);
load_and_store(p, 1);
}
/* if we got here, then we can mis-align longs */
printf("#undef MUST_ALIGN\n");
#else
/* force alignment */
printf("#define MUST_ALIGN\n");
#endif
exit(0);
}
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