Make ieee754 fma tolerate architectures without exception support.

2 files changed, 28 insertions, 7 deletions

diff --git a/ports/ChangeLog.tile b/ports/ChangeLog.tile
index fd722b3e84..99e95db266 100644
--- a/ports/ChangeLog.tile
+++ b/ports/ChangeLog.tile
@@ -1,5 +1,8 @@
 2012-11-05  Chris Metcalf  <cmetcalf@tilera.com>
 
+	* sysdeps/tile/math_private.h: Provide additional no-op defines
+	for exception and rounding macros.
+
 	* sysdeps/tile/tilegx/Makefile: Generate Makefile fragment to determine
 	whether to build elf-init.c and gmon-start.c with -mcmodel=large.
 	* sysdeps/tile/crti.S: Support large memory model.
diff --git a/ports/sysdeps/tile/math_private.h b/ports/sysdeps/tile/math_private.h
index 858db4a051..90dcc3f866 100644
--- a/ports/sysdeps/tile/math_private.h
+++ b/ports/sysdeps/tile/math_private.h
@@ -1,13 +1,31 @@
 #ifndef _MATH_PRIVATE_H
 
+/* Internally, we suppress any use of exception or rounding other
+   than what is supported by the hardware.  This does mean that some
+   code will silently fail to report exceptions, set rounding mode
+   as expected, etc., but it allows math code to compile that otherwise
+   wouldn't (such as math/s_fma.c) and so is valuable.
+
+   We intentionally ignore the "exception" arguments of functions that
+   take an exception, since we can't even evaluate the argument
+   without causing a build failure.  The extra level of statement
+   expression wrapping avoids "statement with no effect" warnings.
+   Since the callers don't check for errors anyway, we just claim
+   success in every case.
+
+   The overrides for libc_ functions must happen before we include
+   the generic math_private.h, and the overrides for regular
+   <fenv.h> functions must happen afterwards, to avoid clashing with
+   the declarations of those functions.  */
+
+#define libc_fesetround(rnd)			({ 0; })
+#define libc_fetestexcept(exc)			({ 0; })
+#define libc_feholdexcept_setround(env, exc)	({ (void) (env); 0; })
+#define libc_feupdateenv_test(env, exc)		({ (void) (env); 0; })
+
 #include_next <math_private.h>
 
-/* We have no exception support, so feraiseexcept() must be a no-op.
-   And since we don't define FE_INVALID, FE_DIVBYZERO, etc., we
-   must ignore the argument of feraiseexcept() as well.  we return
-   "1" to indicate we failed to raise an exception, though none of
-   the callers in glibc actually care.  The extra level of statement
-   expression wrapping avoids "statement with no effect" warnings.  */
-#define feraiseexcept(excepts) ({ 1; })
+#define feraiseexcept(excepts)			({ 0; })
+#define feclearexcept(exc)			({ 0; })
 
 #endif