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* lib/autoconf/c.m4 (AC_C_BIGENDIAN): Guess endianness by grep'ing

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magic values from an object file when cross-compiling.
Based on code by Guido Draheim <Guido.Draheim@gmx.de>.
This commit is contained in:
Alexandre Duret-Lutz 2001-08-12 12:22:29 +00:00
parent 14a3c0c717
commit 6667f46047
4 changed files with 44 additions and 11 deletions

6
ChangeLog

@ -1,3 +1,9 @@
2001-08-11 Alexandre Duret-Lutz <duret_g@epita.fr>
* lib/autoconf/c.m4 (AC_C_BIGENDIAN): Guess endianness by grep'ing
magic values from an object file when cross-compiling.
Based on code by Guido Draheim <Guido.Draheim@gmx.de>.
2001-08-10 Akim Demaille <akim@epita.fr>
* bin/autom4te.in (&handle_output): Don't use `grep' with side

2
NEWS

@ -10,6 +10,8 @@
- --force, -f
** Bug fixes
- The top level $prefix is propagated to the AC_CONFIG_SUBDIRS configures.
** C Macros
- AC_C_BIGENDIAN supports the cross-compiling case.
* Major changes in Autoconf 2.52
** Documentation

1
THANKS

@ -56,6 +56,7 @@ Godmar Back gback@cs.utah.edu
Gordon Matzigkeit gord@trick.fig.org
Graham Jenkins c714553@vus415.telstra.com.au
Greg A. Woods woods@weird.com
Guido Draheim Guido.Draheim@gmx.de
Guido Flohr gufl0000@stud.uni-sb.de
Guillermo Gomez gomez@mi.uni-erlangen.de
Hans Olsson Hans.Olsson@dna.lth.se

46
lib/autoconf/c.m4

@ -832,8 +832,7 @@ fi
# --------------
AC_DEFUN([AC_C_BIGENDIAN],
[AC_CACHE_CHECK(whether byte ordering is bigendian, ac_cv_c_bigendian,
[ac_cv_c_bigendian=unknown
# See if sys/param.h defines the BYTE_ORDER macro.
[# See if sys/param.h defines the BYTE_ORDER macro.
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <sys/types.h>
#include <sys/param.h>
],
@ -847,9 +846,8 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <sys/types.h>
], [#if BYTE_ORDER != BIG_ENDIAN
not big endian
#endif
])], [ac_cv_c_bigendian=yes],
[ac_cv_c_bigendian=no])])
if test $ac_cv_c_bigendian = unknown; then
])], [ac_cv_c_bigendian=yes], [ac_cv_c_bigendian=no])],
[# It does not; compile a test program.
AC_TRY_RUN(
[int
main ()
@ -862,13 +860,39 @@ main ()
} u;
u.l = 1;
exit (u.c[sizeof (long) - 1] == 1);
}], ac_cv_c_bigendian=no, ac_cv_c_bigendian=yes)
fi])
if test $ac_cv_c_bigendian = yes; then
AC_DEFINE(WORDS_BIGENDIAN, 1,
[Define if your processor stores words with the most significant
byte first (like Motorola and SPARC, unlike Intel and VAX).])
}], [ac_cv_c_bigendian=no], [ac_cv_c_bigendian=yes],
[# try to guess the endianess by grep'ing values into an object file
ac_cv_c_bigendian=unknown
AC_COMPILE_IFELSE(
[short ascii_mm[[]] = { 0x4249, 0x4765, 0x6E44, 0x6961, 0x6E53, 0x7953, 0 };
short ascii_ii[[]] = { 0x694C, 0x5454, 0x656C, 0x6E45, 0x6944, 0x6E61, 0 };
void _ascii () { char *s = (char *) ascii_mm; s = (char *) ascii_ii; }
short ebcdic_ii[[]] = { 0x89D3, 0xE3E3, 0x8593, 0x95C5, 0x89C4, 0x9581, 0 };
short ebcdic_mm[[]] = { 0xC2C9, 0xC785, 0x95C4, 0x8981, 0x95E2, 0xA8E2, 0 };
void _ebcdic () { char *s = (char *) ebcdic_mm; s = (char *) ebcdic_ii; }
int main () { _ascii (); _ebcdic (); return 0; }],
[if test `grep -l BIGenDianSyS conftest.$ac_objext` ; then
ac_cv_c_bigendian=yes
fi
if test `grep -l LiTTleEnDian conftest.$ac_objext` ; then
if test "$ac_cv_c_bigendian" = unknown; then
ac_cv_c_bigendian=no
else
# finding both strings is unlikely to happen, but who knows?
ac_cv_c_bigendian=unknown
fi
fi])])])])
case $ac_cv_c_bigendian in
yes)
AC_DEFINE(WORDS_BIGENDIAN, 1,
[Define if your processor stores words with the most significant
byte first (like Motorola and SPARC, unlike Intel and VAX).]);;
no)
;;
*)
AC_MSG_ERROR([unknown endianess
presetting ac_cv_c_bigendian=no (or yes) will help]);;
esac
])# AC_C_BIGENDIAN