[boost] Patch for numeric/interval for better Tru64/CXX support.

From: Markus Schöpflin (markus.schoepflin_at_[hidden])
Date: 2006-01-10 06:33:04

Hello,

support for this platform has recently appeared in Boost but currently 
there are a number of test failures.

Some of these test failures can be attributed to the fact that the 
regression tests are compiled without dynamic rounding mode enabled. Cxx 
needs an extra command line flag (-fprm d) for this.

If I understand things correctly, the interval library relies on dynamic 
rounding to be always enabled, therefore I propose attached patch which 
checks this for Tru64/cxx.

Note that when this patch is applied, all interval tests will fail for 
Tru64/cxx, but this can be fixed by modifying the test Jamfile to enable 
dynamic rounding for the tests. If the patch is accepted, I will fix this 
or provide a patch, whichever is preferred.

Attached patch also changes the test for __DECCXX__ to __DECCXX, because 
this is the macro that the Tru64/cxx compiler defines. Also I'm wondering 
what the test for __digital__ is supposed to do, AFAIK there are only cxx 
and g++ available for this platform anyway.

The same problem exists for g++ on alpha but I don't know if the presence 
of dynamic rounding can be checked for this compiler. Anyway, the needed 
flag to enable dynamic rounding is -mfp-rounding-mode=d on this compiler. I 
could add this to the test Jamfile, too.

Note that enabling dynamic rounding doesn't clear all errors, but it would 
be a start and perhaps enable me or others to root out the other errors and 
achieve proper support of Alpha hardware in the interval library.

Markus

Index: alpha_rounding_control.hpp
===================================================================
RCS file: /cvsroot/boost/boost/boost/numeric/interval/detail/alpha_rounding_control.hpp,v
retrieving revision 1.2
diff -u -w -r1.2 alpha_rounding_control.hpp
--- alpha_rounding_control.hpp	27 Sep 2005 06:08:10 -0000	1.2
+++ alpha_rounding_control.hpp	10 Jan 2006 11:05:03 -0000
@@ -14,7 +14,7 @@
 #error This header only works on Alpha CPUs.
 #endif
 
-#if defined(__GNUC__) || defined(__digital__) || defined(__DECCXX__)
+#if defined(__GNUC__) || defined(__digital__) || defined(__DECCXX)
 
 namespace boost {
 namespace numeric {
@@ -49,7 +49,12 @@
     static void to_nearest()  { set_rounding_mode(mode_to_nearest.dmode);  }
     static void toward_zero() { set_rounding_mode(mode_toward_zero.dmode); }
     };
-#elif defined(__digital__) || defined(__DECCXX__)
+#elif defined(__digital__) || defined(__DECCXX)
+
+#if defined(__DECCXX) && !(defined(__FLT_ROUNDS) && __FLT_ROUNDS == -1)
+#error Dynamic rounding mode not enabled. See cxx man page for details.
+#endif
+
 #   include <float.h> // write_rnd() and read_rnd()
 
     struct alpha_rounding_control