Re: new module 'isnan-nolibm'

[Bruno Haible]

Daniel Jacobowitz wrote:
> That hasn't been the full story for a while.  FPA (the obsolete,
> usually emulated floating point format) does this, but all modern
> systems use VFP word ordering, even if they have only software
> floating point.

Thanks for pointing this out. I'm changing the macro to not assume anything
about the endianness then:

--- m4/isnan.m4 24 Feb 2007 19:08:56 -0000      1.1
+++ m4/isnan.m4 25 Feb 2007 01:56:12 -0000
@@ -92,14 +92,17 @@
         [gl_cv_cc_double_expbit0=`cat conftest.out`],
         [gl_cv_cc_double_expbit0="unknown"],
         [
-          dnl On ARM, integer types are stored in little-endian byte order,
-          dnl but floats are stored in big-endian word order.
+          dnl On ARM, there are two 'double' floating-point formats, used by
+          dnl different sets of instructions: The older FPA instructions assume
+          dnl that they are stored in big-endian word order, while the words
+          dnl (like integer types) are stored in little-endian byte order.
+          dnl The newer VFP instructions assume little-endian order 
consistenly.
           AC_EGREP_CPP([mixed_endianness], [
 #if defined arm || defined __arm || defined __arm__
   mixed_endianness
 #endif
             ],
-            [gl_cv_cc_double_expbit0="word 0 bit 20"],
+            [gl_cv_cc_double_expbit0="unknown"],
             [
               AC_C_BIGENDIAN(
                 [gl_cv_cc_double_expbit0="word 0 bit 20"],