Author: ngie
Date: Wed Oct 14 20:22:12 2015
New Revision: 289332
URL: https://svnweb.freebsd.org/changeset/base/289332

Log:
  Fix test-fenv:test_dfl_env when run on some amd64 CPUs
  
  Compare the fields that the AMD [1] and Intel [2] specs say will be
  set once fnstenv returns.
  
  Not all amd64 capable processors zero out the env.__x87.__other field
  (example: AMD Opteron 6308). The AMD64/x64 specs aren't explicit on what the
  env.__x87.__other field will contain after fnstenv is executed, so the values
  in env.__x87.__other could be filled with arbitrary data depending on how the
  CPU-specific implementation of fnstenv.
  
  1. http://support.amd.com/TechDocs/26569_APM_v5.pdf
  2. http://www.intel.com/Assets/en_US/PDF/manual/253666.pdf
  
  Discussed with: kib, Anton Rang <anton.r...@isilon.com>
  Reviewed by: Daniel O'Connor <dar...@dons.net.au> (earlier patch; 
pre-generalization)
  MFC after: 1 week
  Sponsored by: EMC / Isilon Storage Division
  Reported by: Bill Morchin <wmorc...@isilon.com>

Modified:
  head/tools/regression/lib/msun/test-fenv.c

Modified: head/tools/regression/lib/msun/test-fenv.c
==============================================================================
--- head/tools/regression/lib/msun/test-fenv.c  Wed Oct 14 19:30:04 2015        
(r289331)
+++ head/tools/regression/lib/msun/test-fenv.c  Wed Oct 14 20:22:12 2015        
(r289332)
@@ -133,8 +133,35 @@ test_dfl_env(void)
        fenv_t env;
 
        fegetenv(&env);
+
+#ifdef __amd64__
+       /*
+        * Compare the fields that the AMD [1] and Intel [2] specs say will be
+        * set once fnstenv returns.
+        *
+        * Not all amd64 capable processors implement the fnstenv instruction
+        * by zero'ing out the env.__x87.__other field (example: AMD Opteron
+        * 6308). The AMD64/x64 specs aren't explicit on what the
+        * env.__x87.__other field will contain after fnstenv is executed, so
+        * the values in env.__x87.__other could be filled with arbitrary
+        * data depending on how the CPU implements fnstenv.
+        *
+        * 1. http://support.amd.com/TechDocs/26569_APM_v5.pdf
+        * 2. http://www.intel.com/Assets/en_US/PDF/manual/253666.pdf
+        */
+       assert(memcmp(&env.__mxcsr, &FE_DFL_ENV->__mxcsr,
+           sizeof(env.__mxcsr)) == 0);
+       assert(memcmp(&env.__x87.__control, &FE_DFL_ENV->__x87.__control,
+           sizeof(env.__x87.__control)) == 0);
+       assert(memcmp(&env.__x87.__status, &FE_DFL_ENV->__x87.__status,
+           sizeof(env.__x87.__status)) == 0);
+       assert(memcmp(&env.__x87.__tag, &FE_DFL_ENV->__x87.__tag,
+           sizeof(env.__x87.__tag)) == 0);
+#else
        assert(memcmp(&env, FE_DFL_ENV, sizeof(env)) == 0);
 #endif
+
+#endif
        assert(fetestexcept(FE_ALL_EXCEPT) == 0);
 }
 
_______________________________________________
svn-src-head@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"

Reply via email to