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-rw-r--r--sysdeps/alpha/fpu/fesetenv.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/sysdeps/alpha/fpu/fesetenv.c b/sysdeps/alpha/fpu/fesetenv.c
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+++ b/sysdeps/alpha/fpu/fesetenv.c
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+/* Install given floating-point environment.
+   Copyright (C) 1997 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Richard Henderson <rth@tamu.edu>, 1997
+
+   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>
+
+void
+fesetenv (const fenv_t *envp)
+{
+  unsigned long fpcr;
+  fenv_t env;
+
+  /* Magic encoding of default values: high bit set (never possible for a
+     user-space address) is not indirect.  And we don't even have to get
+     rid of it since we mask things around just below.  */
+  if ((long)envp >= 0)
+    env = *envp;
+  else
+    env = (unsigned long)envp;
+
+  /* Reset the rounding mode with the hardware fpcr.  Note that the following
+     system call is an implied trap barrier for our modification.  */
+  __asm__ __volatile__("excb; mf_fpcr %0" : "=f"(fpcr));
+  fpcr = (fpcr & ~(3UL << 58)) | (env & (3UL << 58));
+  __asm__ __volatile__("mt_fpcr %0" : : "f"(fpcr));
+
+  /* Reset the exception status and mask with the kernel's FP code.  */
+  __ieee_set_fp_control(env & (FE_ALL_EXCEPT | 0x3e));
+}