+2000-11-21 Andreas Jaeger <aj@suse.de>
+
+ * g77.texi (Floating-point Exception Handling): Use feenableexcept
+ in example.
+ (Floating-point precision): Change to match above change.
+
Sun Nov 19 17:29:22 2000 Matthias Klose <doko@marvin.itso-berlin.de>
* g77.texi (Floating-point precision): Adjust example
and m68k GNU systems you can do this with a technique similar to that
for turning on floating-point exceptions
(@pxref{Floating-point Exception Handling}).
-The control word could be set to double precision by
-replacing the @code{__setfpucw} call or the @code{_FPU_SETCW} macro with one like this:
+The control word could be set to double precision by some code like this
+one:
@smallexample
+#include <fpu_control.h>
@{
fpu_control_t cw = (_FPU_DEFAULT & ~_FPU_EXTENDED) | _FPU_DOUBLE;
_FPU_SETCW(cw);
be invoked at startup using @code{gcc}'s @code{constructor} attribute.
For example, just compiling and linking the following C code with your
program will turn on exception trapping for the ``common'' exceptions
-on an x86-based GNU system:
+on a GNU system using glibc 2.2 or newer:
@smallexample
-#include <fpu_control.h>
+#define _GNU_SOURCE 1
+#include <fenv.h>
static void __attribute__ ((constructor))
trapfpe ()
@{
- fpu_control_t cw =
- _FPU_DEFAULT &
- ~(_FPU_MASK_IM | _FPU_MASK_ZM | _FPU_MASK_OM);
- _FPU_SETCW(cw);
+ /* Enable some exceptions. At startup all exceptions are masked. */
+
+ feenableexcept (FE_INVALID|FE_DIVBYZERO|FE_OVERFLOW);
@}
@end smallexample