Chris@40: dnl @synopsis MN_C_FIND_ENDIAN
Chris@40: dnl
Chris@40: dnl Determine endian-ness of target processor.
Chris@40: dnl @version 1.1	Mar 03 2002
Chris@40: dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com>
Chris@40: dnl
Chris@40: dnl Majority written from scratch to replace the standard autoconf macro 
Chris@40: dnl AC_C_BIGENDIAN. Only part remaining from the original it the invocation
Chris@40: dnl of the AC_TRY_RUN macro.
Chris@40: dnl
Chris@40: dnl Permission to use, copy, modify, distribute, and sell this file for any 
Chris@40: dnl purpose is hereby granted without fee, provided that the above copyright 
Chris@40: dnl and this permission notice appear in all copies.  No representations are
Chris@40: dnl made about the suitability of this software for any purpose.  It is 
Chris@40: dnl provided "as is" without express or implied warranty.
Chris@40: 
Chris@40: dnl Find endian-ness in the following way:
Chris@40: dnl    1) Look in <endian.h>.
Chris@40: dnl    2) If 1) fails, look in <sys/types.h> and <sys/param.h>.
Chris@40: dnl    3) If 1) and 2) fails and not cross compiling run a test program.
Chris@40: dnl    4) If 1) and 2) fails and cross compiling then guess based on target.
Chris@40: 
Chris@40: AC_DEFUN([MN_C_FIND_ENDIAN],
Chris@40: [AC_CACHE_CHECK(processor byte ordering, 
Chris@40: 	ac_cv_c_byte_order,
Chris@40: 
Chris@40: # Initialize to unknown
Chris@40: ac_cv_c_byte_order=unknown
Chris@40: 
Chris@40: if test x$ac_cv_header_endian_h = xyes ; then
Chris@40: 
Chris@40: 	# First try <endian.h> which should set BYTE_ORDER.
Chris@40: 
Chris@40: 	[AC_TRY_LINK([
Chris@40: 		#include <endian.h>
Chris@40: 		#if BYTE_ORDER != LITTLE_ENDIAN
Chris@40: 			not big endian
Chris@40: 		#endif
Chris@40: 		], return 0 ;, 
Chris@40: 			ac_cv_c_byte_order=little
Chris@40: 		)]
Chris@40: 				
Chris@40: 	[AC_TRY_LINK([
Chris@40: 		#include <endian.h>
Chris@40: 		#if BYTE_ORDER != BIG_ENDIAN
Chris@40: 			not big endian
Chris@40: 		#endif
Chris@40: 		], return 0 ;, 
Chris@40: 			ac_cv_c_byte_order=big
Chris@40: 		)]
Chris@40: 
Chris@40: 	fi
Chris@40: 
Chris@40: if test $ac_cv_c_byte_order = unknown ; then
Chris@40: 
Chris@40: 	[AC_TRY_LINK([
Chris@40: 		#include <sys/types.h>
Chris@40: 		#include <sys/param.h>
Chris@40: 		#if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN
Chris@40: 			bogus endian macros
Chris@40: 		#endif
Chris@40: 		], return 0 ;, 
Chris@40: 
Chris@40: 		[AC_TRY_LINK([
Chris@40: 			#include <sys/types.h>
Chris@40: 			#include <sys/param.h>
Chris@40: 			#if BYTE_ORDER != LITTLE_ENDIAN
Chris@40: 				not big endian
Chris@40: 			#endif
Chris@40: 			], return 0 ;, 
Chris@40: 				ac_cv_c_byte_order=little
Chris@40: 			)]
Chris@40: 				
Chris@40: 		[AC_TRY_LINK([
Chris@40: 			#include <sys/types.h>
Chris@40: 			#include <sys/param.h>
Chris@40: 			#if BYTE_ORDER != LITTLE_ENDIAN
Chris@40: 				not big endian
Chris@40: 			#endif
Chris@40: 			], return 0 ;, 
Chris@40: 				ac_cv_c_byte_order=little
Chris@40: 			)]
Chris@40: 
Chris@40: 		)]
Chris@40: 
Chris@40:  	fi
Chris@40: 
Chris@40: if test $ac_cv_c_byte_order = unknown ; then
Chris@40: 	if test $cross_compiling = yes ; then
Chris@40: 		# This is the last resort. Try to guess the target processor endian-ness
Chris@40: 		# by looking at the target CPU type.	
Chris@40: 		[
Chris@40: 		case "$target_cpu" in
Chris@40: 			alpha* | i?86* | mipsel* | ia64*)
Chris@40: 				ac_cv_c_byte_order=little
Chris@40: 				;;
Chris@40: 			
Chris@40: 			m68* | mips* | powerpc* | hppa* | sparc*)
Chris@40: 				ac_cv_c_byte_order=big
Chris@40: 				;;
Chris@40: 	
Chris@40: 			esac
Chris@40: 		]
Chris@40: 	else
Chris@40: 		AC_TRY_RUN(
Chris@40: 		[[
Chris@40: 		int main (void) 
Chris@40: 		{	/* Are we little or big endian?  From Harbison&Steele.  */
Chris@40: 			union
Chris@40: 			{	long l ;
Chris@40: 				char c [sizeof (long)] ;
Chris@40: 			} u ;
Chris@40: 			u.l = 1 ;
Chris@40: 			return (u.c [sizeof (long) - 1] == 1);
Chris@40: 			}
Chris@40: 			]], , ac_cv_c_byte_order=big, 
Chris@40: 			)
Chris@40: 
Chris@40: 		AC_TRY_RUN(
Chris@40: 		[[int main (void) 
Chris@40: 		{	/* Are we little or big endian?  From Harbison&Steele.  */
Chris@40: 			union
Chris@40: 			{	long l ;
Chris@40: 				char c [sizeof (long)] ;
Chris@40: 			} u ;
Chris@40: 			u.l = 1 ;
Chris@40: 			return (u.c [0] == 1);
Chris@40: 			}]], , ac_cv_c_byte_order=little, 
Chris@40: 			)
Chris@40: 		fi	
Chris@40: 	fi
Chris@40: 
Chris@40: )
Chris@40: 
Chris@40: if test $ac_cv_c_byte_order = big ; then
Chris@40: 	ac_cv_c_big_endian=1
Chris@40: 	ac_cv_c_little_endian=0
Chris@40: elif test $ac_cv_c_byte_order = little ; then
Chris@40: 	ac_cv_c_big_endian=0
Chris@40: 	ac_cv_c_little_endian=1
Chris@40: else
Chris@40: 	ac_cv_c_big_endian=0
Chris@40: 	ac_cv_c_little_endian=0
Chris@40: 
Chris@40: 	AC_MSG_WARN([[*****************************************************************]])
Chris@40: 	AC_MSG_WARN([[*** Not able to determine endian-ness of target processor.       ]])
Chris@40: 	AC_MSG_WARN([[*** The constants CPU_IS_BIG_ENDIAN and CPU_IS_LITTLE_ENDIAN in  ]])
Chris@40: 	AC_MSG_WARN([[*** src/config.h may need to be hand editied.                    ]])
Chris@40: 	AC_MSG_WARN([[*****************************************************************]])
Chris@40: 	fi
Chris@40: 
Chris@40: ]
Chris@40: )# MN_C_FIND_ENDIAN
Chris@40: 
Chris@40: