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