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1 | dnl @synopsis AC_C_FIND_ENDIAN | |
2 | dnl | |
3 | dnl Determine endian-ness of target processor. | |
4 | dnl @version 1.1 Mar 03 2002 | |
5 | dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com> | |
6 | dnl | |
7 | dnl Majority written from scratch to replace the standard autoconf macro | |
8 | dnl AC_C_BIGENDIAN. Only part remaining from the original it the invocation | |
9 | dnl of the AC_TRY_RUN macro. | |
10 | dnl | |
11 | dnl Permission to use, copy, modify, distribute, and sell this file for any | |
12 | dnl purpose is hereby granted without fee, provided that the above copyright | |
13 | dnl and this permission notice appear in all copies. No representations are | |
14 | dnl made about the suitability of this software for any purpose. It is | |
15 | dnl provided "as is" without express or implied warranty. | |
16 | ||
17 | dnl Find endian-ness in the following way: | |
18 | dnl 1) Look in <endian.h>. | |
19 | dnl 2) If 1) fails, look in <sys/types.h> and <sys/param.h>. | |
20 | dnl 3) If 1) and 2) fails and not cross compiling run a test program. | |
21 | dnl 4) If 1) and 2) fails and cross compiling then guess based on target. | |
22 | ||
23 | AC_DEFUN([AC_C_FIND_ENDIAN], | |
24 | [AC_CACHE_CHECK(processor byte ordering, | |
25 | ac_cv_c_byte_order, | |
26 | ||
27 | # Initialize to unknown | |
28 | ac_cv_c_byte_order=unknown | |
29 | ||
30 | if test x$ac_cv_header_endian_h = xyes ; then | |
31 | ||
32 | # First try <endian.h> which should set BYTE_ORDER. | |
33 | ||
34 | [AC_TRY_LINK([ | |
35 | #include <endian.h> | |
36 | #if BYTE_ORDER != LITTLE_ENDIAN | |
37 | not big endian | |
38 | #endif | |
39 | ], return 0 ;, | |
40 | ac_cv_c_byte_order=little | |
41 | )] | |
42 | ||
43 | [AC_TRY_LINK([ | |
44 | #include <endian.h> | |
45 | #if BYTE_ORDER != BIG_ENDIAN | |
46 | not big endian | |
47 | #endif | |
48 | ], return 0 ;, | |
49 | ac_cv_c_byte_order=big | |
50 | )] | |
51 | ||
52 | fi | |
53 | ||
54 | if test $ac_cv_c_byte_order = unknown ; then | |
55 | ||
56 | [AC_TRY_LINK([ | |
57 | #include <sys/types.h> | |
58 | #include <sys/param.h> | |
59 | #if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN | |
60 | bogus endian macros | |
61 | #endif | |
62 | ], return 0 ;, | |
63 | ||
64 | [AC_TRY_LINK([ | |
65 | #include <sys/types.h> | |
66 | #include <sys/param.h> | |
67 | #if BYTE_ORDER != LITTLE_ENDIAN | |
68 | not big endian | |
69 | #endif | |
70 | ], return 0 ;, | |
71 | ac_cv_c_byte_order=little | |
72 | )] | |
73 | ||
74 | [AC_TRY_LINK([ | |
75 | #include <sys/types.h> | |
76 | #include <sys/param.h> | |
77 | #if BYTE_ORDER != LITTLE_ENDIAN | |
78 | not big endian | |
79 | #endif | |
80 | ], return 0 ;, | |
81 | ac_cv_c_byte_order=little | |
82 | )] | |
83 | ||
84 | )] | |
85 | ||
86 | fi | |
87 | ||
88 | if test $ac_cv_c_byte_order = unknown ; then | |
89 | if test $cross_compiling = yes ; then | |
90 | # This is the last resort. Try to guess the target processor endian-ness | |
91 | # by looking at the target CPU type. | |
92 | [ | |
93 | case "$target_cpu" in | |
94 | alpha* | i?86* | mipsel* | ia64*) | |
95 | ac_cv_c_byte_order=little | |
96 | ;; | |
97 | ||
98 | m68* | mips* | powerpc* | hppa* | sparc*) | |
99 | ac_cv_c_byte_order=big | |
100 | ;; | |
101 | ||
102 | esac | |
103 | ] | |
104 | else | |
105 | AC_TRY_RUN( | |
106 | [[ | |
107 | int main (void) | |
108 | { /* Are we little or big endian? From Harbison&Steele. */ | |
109 | union | |
110 | { long l ; | |
111 | char c [sizeof (long)] ; | |
112 | } u ; | |
113 | u.l = 1 ; | |
114 | return (u.c [sizeof (long) - 1] == 1); | |
115 | } | |
116 | ]], , ac_cv_c_byte_order=big, | |
117 | ) | |
118 | ||
119 | AC_TRY_RUN( | |
120 | [[int main (void) | |
121 | { /* Are we little or big endian? From Harbison&Steele. */ | |
122 | union | |
123 | { long l ; | |
124 | char c [sizeof (long)] ; | |
125 | } u ; | |
126 | u.l = 1 ; | |
127 | return (u.c [0] == 1); | |
128 | }]], , ac_cv_c_byte_order=little, | |
129 | ) | |
130 | fi | |
131 | fi | |
132 | ||
133 | ) | |
134 | ||
135 | if test $ac_cv_c_byte_order = big ; then | |
136 | ac_cv_c_big_endian=1 | |
137 | ac_cv_c_little_endian=0 | |
138 | elif test $ac_cv_c_byte_order = little ; then | |
139 | ac_cv_c_big_endian=0 | |
140 | ac_cv_c_little_endian=1 | |
141 | else | |
142 | ac_cv_c_big_endian=0 | |
143 | ac_cv_c_little_endian=0 | |
144 | ||
145 | AC_MSG_WARN([[*****************************************************************]]) | |
146 | AC_MSG_WARN([[*** Not able to determine endian-ness of target processor. ]]) | |
147 | AC_MSG_WARN([[*** The constants CPU_IS_BIG_ENDIAN and CPU_IS_LITTLE_ENDIAN in ]]) | |
148 | AC_MSG_WARN([[*** src/config.h may need to be hand editied. ]]) | |
149 | AC_MSG_WARN([[*****************************************************************]]) | |
150 | fi | |
151 | ||
152 | ] | |
153 | )# AC_C_FIND_ENDIAN | |
154 | ||
155 |