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feenablexcept, fedisableexcept, fegetexcept
- To: libc-alpha at sourceware dot cygnus dot com
- Subject: feenablexcept, fedisableexcept, fegetexcept
- From: Andreas Jaeger <aj at suse dot de>
- Date: 02 Nov 1999 09:09:23 +0100
- Cc: "David H. Munro" <munro at icf dot llnl dot gov>
After some discussions with Ulrich, here comes a new patch to
implement handling of floating point traps in a platform independent
way for glibc.
I've only added the functions for ix86. If this gets added to glibc
2.2., I ask the various port maintainers to send patches for their
platforms.
Andreas
1999-11-02 Andreas Jaeger <aj@suse.de>
* Versions.def: Add version GLIBC_2.2 for libm.
* math/fenv.h: Add prototypes for fegetexcept, feenableexcept and
fedisableexcept.
* sysdeps/generic/feenablxcpt.c: Stub file.
* sysdeps/generic/fedisblxcpt.c: Stub file.
* sysdeps/generic/fegetexcept.c: Stub file.
* sysdeps/i386/fpu/fedisblxcpt.c: New file.
* sysdeps/i386/fpu/feenablxcpt.c: New file.
* sysdeps/i386/fpu/fegetexcept.c: New file.
* math/Makefile (libm-support): Add new files.
* math/Versions: Add new functions with version GLIBC_2.2.
* manual/arith.texi (Control Functions): Document fegetexcept,
feenableexcept and fedisableexcept.
============================================================
Index: Versions.def
--- Versions.def 1999/11/01 15:53:37 1.12
+++ Versions.def 1999/11/02 08:07:30
@@ -26,6 +26,7 @@
GLIBC_2.0
GLIBC_2.1 GLIBC_2.0
GLIBC_2.1.3 GLIBC_2.1
+ GLIBC_2.2 GLIBC_2.1.3
}
libmachuser {
GLIBC_2.0
============================================================
Index: math/fenv.h
--- math/fenv.h 1999/10/31 23:07:49 1.7
+++ math/fenv.h 1999/11/02 08:07:30
@@ -109,6 +109,22 @@
according to saved exceptions. */
extern int feupdateenv (__const fenv_t *__envp) __THROW;
+#ifdef __USE_GNU
+
+/* Enable individual exceptions. Will not enable more exceptions than
+ EXCEPTS specifies. Returns the previous enabled exceptions if all
+ exceptions are successfull set, otherwise returns -1. */
+extern int feenableexcept (int __excepts) __THROW;
+
+/* Disable individual exceptions. Will not disable more exceptions than
+ EXCEPTS specifies. Returns the previous enabled exceptions if all
+ exceptions are successfull disabled, otherwise returns -1. */
+extern int fedisableexcept (int __excepts) __THROW;
+
+/* Return enabled exceptions. */
+extern int fegetexcept (void) __THROW;
+#endif
+
__END_DECLS
#endif /* fenv.h */
============================================================
Index: math/Makefile
--- math/Makefile 1999/11/01 02:27:37 1.90
+++ math/Makefile 1999/11/02 08:07:30
@@ -39,7 +39,8 @@
libm-support = k_standard s_lib_version s_matherr s_signgam \
fclrexcpt fgetexcptflg fraiseexcpt fsetexcptflg \
ftestexcept fegetround fesetround fegetenv feholdexcpt \
- fesetenv feupdateenv t_exp
+ fesetenv feupdateenv t_exp fedisblxcpt feenablxcpt \
+ fegetexcept
libm-calls = e_acos e_acosh e_asin e_atan2 e_atanh e_cosh e_exp e_fmod \
e_hypot e_j0 e_j1 e_jn e_lgamma_r e_log e_log10 e_pow \
e_rem_pio2 e_remainder e_scalb e_sinh e_sqrt e_gamma_r \
============================================================
Index: math/Versions
--- math/Versions 1999/10/31 23:06:39 1.6
+++ math/Versions 1999/11/02 08:07:31
@@ -158,4 +158,8 @@
feclearexcept; fegetenv; fegetexceptflag; feraiseexcept;
fesetenv; fesetexceptflag; feupdateenv;
}
+ GLIBC_2.2 {
+ # fp environment function
+ feenableexcept; fedisableexcept; fegetexcept;
+ }
}
============================================================
Index: manual/arith.texi
--- manual/arith.texi 1999/10/31 23:05:33 1.55
+++ manual/arith.texi 1999/11/02 08:07:34
@@ -828,6 +828,42 @@
non-zero value otherwise.
@end deftypefun
+@noindent
+To control for individual exceptions if raising them causes a trap to
+occur, you can use the following two functions.
+
+@strong{Portability Note:} These functions are all GNU extensions.
+
+@comment fenv.h
+@comment GNU
+@deftypefun int feenableexcept (int @var{excepts})
+This functions enables traps for each of the exceptions as indicated by
+the parameter @var{except}. The individual excepetions are described in
+@ref{Examining the FPU status word}. Only the specified exceptions are
+enabled, the status of the other exceptions is not changed.
+
+The function returns the previous enabled exceptions in case the
+operation was successful, @code{-1} otherwise.
+@end deftypefun
+
+@comment fenv.h
+@comment GNU
+@deftypefun int fedisableexcept (int @var{excepts})
+This functions disables traps for each of the exceptions as indicated by
+the parameter @var{except}. The individual excepetions are described in
+@ref{Examining the FPU status word}. Only the specified exceptions are
+disabled, the status of the other exceptions is not changed.
+
+The function returns the previous enabled exceptions in case the
+operation was successful, @code{-1} otherwise.
+@end deftypefun
+
+@comment fenv.h
+@comment GNU
+@deftypefun int fegetexcept (int @var{excepts})
+The function returns a bitmask of all currently enabled exceptions. It
+returns @code{-1} in case of failure.
+
@node Arithmetic Functions
@section Arithmetic Functions
============================================================
Index: sysdeps/generic/feenablxcpt.c
--- sysdeps/generic/feenablxcpt.c created
+++ sysdeps/generic/feenablxcpt.c Tue Nov 2 08:54:59 1999 1.1
@@ -0,0 +1,30 @@
+/* Enable floating-point exceptions.
+ Copyright (C) 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Andreas Jaeger <aj@suse.de>, 1999.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <fenv.h>
+
+int
+feenableexcept (int excepts)
+{
+ /* Signal failure. */
+ return -1;
+}
+stub_warning (feenableexcept)
+#include <stub-tag.h>
============================================================
Index: sysdeps/generic/fedisblxcpt.c
--- sysdeps/generic/fedisblxcpt.c created
+++ sysdeps/generic/fedisblxcpt.c Tue Nov 2 08:56:59 1999 1.1
@@ -0,0 +1,30 @@
+/* Disable floating-point exceptions.
+ Copyright (C) 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Andreas Jaeger <aj@suse.de>, 1999.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <fenv.h>
+
+int
+fedisableexcept (int excepts)
+{
+ /* Signal failure. */
+ return -1;
+}
+stub_warning (fedisableexcept)
+#include <stub-tag.h>
============================================================
Index: sysdeps/generic/fegetexcept.c
--- sysdeps/generic/fegetexcept.c created
+++ sysdeps/generic/fegetexcept.c Tue Nov 2 08:56:16 1999 1.1
@@ -0,0 +1,30 @@
+/* Get floating-point exceptions.
+ Copyright (C) 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Andreas Jaeger <aj@suse.de>, 1999.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <fenv.h>
+
+int
+fegetexcept (void)
+{
+ /* Signal failure. */
+ return -1;
+}
+stub_warning (fegetexcept)
+#include <stub-tag.h>
============================================================
Index: sysdeps/i386/fpu/fedisblxcpt.c
--- sysdeps/i386/fpu/fedisblxcpt.c created
+++ sysdeps/i386/fpu/fedisblxcpt.c Tue Nov 2 08:49:21 1999 1.1
@@ -0,0 +1,39 @@
+/* Disable floating-point exceptions.
+ Copyright (C) 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Andreas Jaeger <aj@suse.de>, 1999.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <fenv.h>
+
+int
+fedisableexcept (int excepts)
+{
+ unsigned short int new_exc, old_exc;
+
+ /* Get the current control word. */
+ __asm__ ("fstcw %0" : "=m" (*&new_exc));
+
+ old_exc = new_exc & FE_ALL_EXCEPT;
+
+ excepts &= FE_ALL_EXCEPT;
+
+ new_exc &= ~excepts;
+ __asm__ ("fldcw %0" : : "m" (*&new_exc));
+
+ return old_exc;
+}
============================================================
Index: sysdeps/i386/fpu/feenablxcpt.c
--- sysdeps/i386/fpu/feenablxcpt.c created
+++ sysdeps/i386/fpu/feenablxcpt.c Tue Nov 2 08:47:56 1999 1.1
@@ -0,0 +1,38 @@
+/* Enable floating-point exceptions.
+ Copyright (C) 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Andreas Jaeger <aj@suse.de>, 1999.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <fenv.h>
+
+int
+feenableexcept (int excepts)
+{
+ unsigned short int new_exc, old_exc;
+
+ /* Get the current control word. */
+ __asm__ ("fstcw %0" : "=m" (*&new_exc));
+
+ excepts &= FE_ALL_EXCEPT;
+ old_exc = new_exc & FE_ALL_EXCEPT;
+
+ new_exc |= excepts;
+ __asm__ ("fldcw %0" : : "m" (*&new_exc));
+
+ return old_exc;
+}
============================================================
Index: sysdeps/i386/fpu/fegetexcept.c
--- sysdeps/i386/fpu/fegetexcept.c created
+++ sysdeps/i386/fpu/fegetexcept.c Tue Nov 2 08:50:41 1999 1.1
@@ -0,0 +1,32 @@
+/* Get enabled floating-point exceptions.
+ Copyright (C) 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Andreas Jaeger <aj@suse.de>, 1999.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <fenv.h>
+
+int
+fegetexcept (void)
+{
+ unsigned short int exc;
+
+ /* Get the current control word. */
+ __asm__ ("fstcw %0" : "=m" (*&exc));
+
+ return exc & FE_ALL_EXCEPT;
+}
--
Andreas Jaeger
SuSE Labs aj@suse.de
private aj@arthur.rhein-neckar.de