diff options
Diffstat (limited to 'erts')
| -rw-r--r-- | erts/aclocal.m4 | 65 |
1 files changed, 54 insertions, 11 deletions
diff --git a/erts/aclocal.m4 b/erts/aclocal.m4 index 9c5bcd6dc6..a76594d86f 100644 --- a/erts/aclocal.m4 +++ b/erts/aclocal.m4 @@ -621,25 +621,68 @@ AC_DEFUN([AC_C_DOUBLE_MIDDLE_ENDIAN], [AC_CACHE_CHECK(whether double word ordering is middle-endian, ac_cv_c_double_middle_endian, [# It does not; compile a test program. AC_RUN_IFELSE( -[AC_LANG_SOURCE([[int +[AC_LANG_SOURCE([[#include <stdlib.h> + +int main(void) { int i = 0; int zero = 0; + int bigendian; + int zero_index = 0; + + union + { + long int l; + char c[sizeof (long int)]; + } u; + + /* we'll use the one with 32-bit words */ + union + { + double d; + unsigned int c[2]; + } vint; + + union + { + double d; + unsigned long c[2]; + } vlong; + union { double d; - char c[sizeof (double)]; - } v; - v.d = 1.0; - - - while (i < sizeof(double) / 2) + unsigned short c[2]; + } vshort; + + + /* Are we little or big endian? From Harbison&Steele. */ + u.l = 1; + bigendian = (u.c[sizeof (long int) - 1] == 1); + + zero_index = bigendian ? 1 : 0; + + vint.d = 1.0; + vlong.d = 1.0; + vshort.d = 1.0; + + if (sizeof(unsigned int) == 4) + { + if (vint.c[zero_index] != 0) + zero = 1; + } + else if (sizeof(unsigned long) == 4) + { + if (vlong.c[zero_index] != 0) + zero = 1; + } + else if (sizeof(unsigned short) == 4) { - if (v.c[i] != 0) + if (vshort.c[zero_index] != 0) zero = 1; - ++i; } + exit (zero); } ]])], @@ -656,7 +699,7 @@ case $ac_cv_c_double_middle_endian in $2 ;; *) m4_default([$3], - [AC_MSG_ERROR([unknown double endianness + [AC_MSG_WARN([unknown double endianness presetting ac_cv_c_double_middle_endian=no (or yes) will help])]) ;; esac ])# AC_C_DOUBLE_MIDDLE_ENDIAN @@ -1394,7 +1437,7 @@ fi case X$erl_xcomp_double_middle_endian in X) ;; - Xyes|Xno) ac_cv_c_double_middle_endian=$erl_xcomp_double_middle_endian;; + Xyes|Xno|Xunknown) ac_cv_c_double_middle_endian=$erl_xcomp_double_middle_endian;; *) AC_MSG_ERROR([Bad erl_xcomp_double_middle_endian value: $erl_xcomp_double_middle_endian]);; esac |