cannam@85: dnl @synopsis MN_C_FIND_ENDIAN
cannam@85: dnl
cannam@85: dnl Determine endian-ness of target processor.
cannam@85: dnl @version 1.1	Mar 03 2002
cannam@85: dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com>
cannam@85: dnl
cannam@85: dnl Majority written from scratch to replace the standard autoconf macro 
cannam@85: dnl AC_C_BIGENDIAN. Only part remaining from the original it the invocation
cannam@85: dnl of the AC_TRY_RUN macro.
cannam@85: dnl
cannam@85: dnl Permission to use, copy, modify, distribute, and sell this file for any 
cannam@85: dnl purpose is hereby granted without fee, provided that the above copyright 
cannam@85: dnl and this permission notice appear in all copies.  No representations are
cannam@85: dnl made about the suitability of this software for any purpose.  It is 
cannam@85: dnl provided "as is" without express or implied warranty.
cannam@85: 
cannam@85: dnl Find endian-ness in the following way:
cannam@85: dnl    1) Look in <endian.h>.
cannam@85: dnl    2) If 1) fails, look in <sys/types.h> and <sys/param.h>.
cannam@85: dnl    3) If 1) and 2) fails and not cross compiling run a test program.
cannam@85: dnl    4) If 1) and 2) fails and cross compiling then guess based on target.
cannam@85: 
cannam@85: AC_DEFUN([MN_C_FIND_ENDIAN],
cannam@85: [AC_CACHE_CHECK(processor byte ordering, 
cannam@85: 	ac_cv_c_byte_order,
cannam@85: 
cannam@85: # Initialize to unknown
cannam@85: ac_cv_c_byte_order=unknown
cannam@85: 
cannam@85: if test x$ac_cv_header_endian_h = xyes ; then
cannam@85: 
cannam@85: 	# First try <endian.h> which should set BYTE_ORDER.
cannam@85: 
cannam@85: 	[AC_TRY_LINK([
cannam@85: 		#include <endian.h>
cannam@85: 		#if BYTE_ORDER != LITTLE_ENDIAN
cannam@85: 			not big endian
cannam@85: 		#endif
cannam@85: 		], return 0 ;, 
cannam@85: 			ac_cv_c_byte_order=little
cannam@85: 		)]
cannam@85: 				
cannam@85: 	[AC_TRY_LINK([
cannam@85: 		#include <endian.h>
cannam@85: 		#if BYTE_ORDER != BIG_ENDIAN
cannam@85: 			not big endian
cannam@85: 		#endif
cannam@85: 		], return 0 ;, 
cannam@85: 			ac_cv_c_byte_order=big
cannam@85: 		)]
cannam@85: 
cannam@85: 	fi
cannam@85: 
cannam@85: if test $ac_cv_c_byte_order = unknown ; then
cannam@85: 
cannam@85: 	[AC_TRY_LINK([
cannam@85: 		#include <sys/types.h>
cannam@85: 		#include <sys/param.h>
cannam@85: 		#if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN
cannam@85: 			bogus endian macros
cannam@85: 		#endif
cannam@85: 		], return 0 ;, 
cannam@85: 
cannam@85: 		[AC_TRY_LINK([
cannam@85: 			#include <sys/types.h>
cannam@85: 			#include <sys/param.h>
cannam@85: 			#if BYTE_ORDER != LITTLE_ENDIAN
cannam@85: 				not big endian
cannam@85: 			#endif
cannam@85: 			], return 0 ;, 
cannam@85: 				ac_cv_c_byte_order=little
cannam@85: 			)]
cannam@85: 				
cannam@85: 		[AC_TRY_LINK([
cannam@85: 			#include <sys/types.h>
cannam@85: 			#include <sys/param.h>
cannam@85: 			#if BYTE_ORDER != LITTLE_ENDIAN
cannam@85: 				not big endian
cannam@85: 			#endif
cannam@85: 			], return 0 ;, 
cannam@85: 				ac_cv_c_byte_order=little
cannam@85: 			)]
cannam@85: 
cannam@85: 		)]
cannam@85: 
cannam@85:  	fi
cannam@85: 
cannam@85: if test $ac_cv_c_byte_order = unknown ; then
cannam@85: 	if test $cross_compiling = yes ; then
cannam@85: 		# This is the last resort. Try to guess the target processor endian-ness
cannam@85: 		# by looking at the target CPU type.	
cannam@85: 		[
cannam@85: 		case "$target_cpu" in
cannam@85: 			alpha* | i?86* | mipsel* | ia64*)
cannam@85: 				ac_cv_c_byte_order=little
cannam@85: 				;;
cannam@85: 			
cannam@85: 			m68* | mips* | powerpc* | hppa* | sparc*)
cannam@85: 				ac_cv_c_byte_order=big
cannam@85: 				;;
cannam@85: 	
cannam@85: 			esac
cannam@85: 		]
cannam@85: 	else
cannam@85: 		AC_TRY_RUN(
cannam@85: 		[[
cannam@85: 		int main (void) 
cannam@85: 		{	/* Are we little or big endian?  From Harbison&Steele.  */
cannam@85: 			union
cannam@85: 			{	long l ;
cannam@85: 				char c [sizeof (long)] ;
cannam@85: 			} u ;
cannam@85: 			u.l = 1 ;
cannam@85: 			return (u.c [sizeof (long) - 1] == 1);
cannam@85: 			}
cannam@85: 			]], , ac_cv_c_byte_order=big, 
cannam@85: 			)
cannam@85: 
cannam@85: 		AC_TRY_RUN(
cannam@85: 		[[int main (void) 
cannam@85: 		{	/* Are we little or big endian?  From Harbison&Steele.  */
cannam@85: 			union
cannam@85: 			{	long l ;
cannam@85: 				char c [sizeof (long)] ;
cannam@85: 			} u ;
cannam@85: 			u.l = 1 ;
cannam@85: 			return (u.c [0] == 1);
cannam@85: 			}]], , ac_cv_c_byte_order=little, 
cannam@85: 			)
cannam@85: 		fi	
cannam@85: 	fi
cannam@85: 
cannam@85: )
cannam@85: 
cannam@85: if test $ac_cv_c_byte_order = big ; then
cannam@85: 	ac_cv_c_big_endian=1
cannam@85: 	ac_cv_c_little_endian=0
cannam@85: elif test $ac_cv_c_byte_order = little ; then
cannam@85: 	ac_cv_c_big_endian=0
cannam@85: 	ac_cv_c_little_endian=1
cannam@85: else
cannam@85: 	ac_cv_c_big_endian=0
cannam@85: 	ac_cv_c_little_endian=0
cannam@85: 
cannam@85: 	AC_MSG_WARN([[*****************************************************************]])
cannam@85: 	AC_MSG_WARN([[*** Not able to determine endian-ness of target processor.       ]])
cannam@85: 	AC_MSG_WARN([[*** The constants CPU_IS_BIG_ENDIAN and CPU_IS_LITTLE_ENDIAN in  ]])
cannam@85: 	AC_MSG_WARN([[*** src/config.h may need to be hand editied.                    ]])
cannam@85: 	AC_MSG_WARN([[*****************************************************************]])
cannam@85: 	fi
cannam@85: 
cannam@85: ]
cannam@85: )# MN_C_FIND_ENDIAN
cannam@85: 
cannam@85: