On Fri, Nov 8, 2013 at 2:13 PM, Joseph S. Myers <jos...@codesourcery.com> wrote:
>> Can we introduce a target-dependant source here, in the same way as
>
> Sure, that seems a reasonable thing to do. I think putting a file fenv.c
> in an appropriate subdirectory of libatomic/config will result in it being
> found automatically by the existing search path logic, but you'll need to
> test that.
Attached is the x86 optimized implementation of fenv.c. The source
depends as little as possible on fenv.h definitions - these are
defined by hardware, and for sure won't change soon in
hardware-dependant file.
2013-11-08 Uros Bizjak <ubiz...@gmail.com>
* config/x86/fenv.c: New file.
Bootstrapped and regression tested on x86_64-pc-linux-gnu {,-m32}. The
testing of atomics currently fails on 32bit target due to missing
__atomic_{load,store}_16 functions, so the patch is not adequately
tested yet.
Yes, I have tested that the libatomic's auto-configuration logic works ;)
Uros.
Index: ChangeLog
===================================================================
--- ChangeLog (revision 204574)
+++ ChangeLog (working copy)
@@ -1,3 +1,7 @@
+2013-11-08 Uros Bizjak <ubiz...@gmail.com>
+
+ * config/x86/fenv.c: New file.
+
2013-11-07 Joseph Myers <jos...@codesourcery.com>
* fenv.c: New file.
Index: config/x86/fenv.c
===================================================================
--- config/x86/fenv.c (revision 0)
+++ config/x86/fenv.c (working copy)
@@ -0,0 +1,115 @@
+/* Copyright (C) 2013 Free Software Foundation, Inc.
+
+ This file is part of the GNU Atomic Library (libatomic).
+
+ Libatomic is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ Libatomic 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 General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include "libatomic_i.h"
+
+#ifdef HAVE_FENV_H
+# include <fenv.h>
+#endif
+
+struct fenv
+{
+ unsigned short int __control_word;
+ unsigned short int __unused1;
+ unsigned short int __status_word;
+ unsigned short int __unused2;
+ unsigned short int __tags;
+ unsigned short int __unused3;
+ unsigned int __eip;
+ unsigned short int __cs_selector;
+ unsigned int __opcode:11;
+ unsigned int __unused4:5;
+ unsigned int __data_offset;
+ unsigned short int __data_selector;
+ unsigned short int __unused5;
+};
+
+/* Raise the supported floating-point exceptions from EXCEPTS. Other
+ bits in EXCEPTS are ignored. */
+
+void
+__atomic_feraiseexcept (int excepts __attribute__ ((unused)))
+{
+#ifdef FE_INVALID
+ if (excepts & FE_INVALID)
+ {
+ float f = 0.0f;
+#ifdef __x86_64__
+ volatile float r __attribute__ ((unused));
+ asm volatile ("%vdivss\t{%0, %d0|%d0, %0}" : "+x" (f));
+ r = f; /* Needed to trigger exception. */
+#else
+ asm volatile ("fdiv\t{%y0, %0|%0, %y0}" : "+t" (f));
+ /* No need for fwait, exception is triggered by emitted fstp. */
+#endif
+ }
+#endif
+#ifdef FE_DIVBYZERO
+ if (excepts & FE_DIVBYZERO)
+ {
+ float f = 1.0f, g = 0.0f;
+#ifdef __x86_64__
+ volatile float r __attribute__ ((unused));
+ asm volatile ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
+ r = f; /* Needed to trigger exception. */
+#else
+ asm volatile ("fdivs\t%1" : "+t" (f) : "m" (g));
+ /* No need for fwait, exception is triggered by emitted fstp. */
+#endif
+ }
+#endif
+#ifdef FE_OVERFLOW
+ if (excepts & FE_OVERFLOW)
+ {
+ struct fenv temp;
+ asm volatile ("fnstenv\t%0" : "=m" (temp));
+ temp.__status_word |= 0x08;
+ asm volatile ("fldenv\t%0" : : "m" (temp));
+ asm volatile ("fwait");
+ }
+#endif
+#ifdef FE_UNDERFLOW
+ if (excepts & FE_UNDERFLOW)
+ {
+ struct fenv temp;
+ asm volatile ("fnstenv\t%0" : "=m" (temp));
+ temp.__status_word |= 0x10;
+ asm volatile ("fldenv\t%0" : : "m" (temp));
+ asm volatile ("fwait");
+ }
+#endif
+#ifdef FE_INEXACT
+ if (excepts & FE_INEXACT)
+ {
+ float f = 1.0f, g = 3.0f;
+#ifdef __x86_64__
+ volatile float r __attribute__ ((unused));
+ asm volatile ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
+ r = f; /* Needed to trigger exception. */
+#else
+ asm volatile ("fdivs\t%1" : "+t" (f) : "m" (g));
+ /* No need for fwait, exception is triggered by emitted fstp. */
+#endif
+ }
+#endif
+}
