Update copyright dates with scripts/update-copyrights.

[thirdparty/glibc.git] / sysdeps / unix / sysv / linux / alpha / setfpucw.c

diff --git a/sysdeps/unix/sysv/linux/alpha/setfpucw.c b/sysdeps/unix/sysv/linux/alpha/setfpucw.c
index 5e74c35d883d0c5a1191bdd2602ccf6137b7f2eb..cd8c8a1c34b59893ce8ed04c86ef65dce656134c 100644 (file)
--- a/sysdeps/unix/sysv/linux/alpha/setfpucw.c
+++ b/sysdeps/unix/sysv/linux/alpha/setfpucw.c
@@ -1,78 +1,61 @@
 /* Set FP exception mask and rounding mode.
-   Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
+   Copyright (C) 1996-2019 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    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.
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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.
+   Lesser 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.  */
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
 
 #include <fpu_control.h>
-#include <asm/fpu.h>
+#include <fenv_libc.h>
 
 
-extern void            __ieee_set_fp_control (unsigned long);
-extern unsigned long   __ieee_get_fp_control (void);
-
-static inline unsigned long
-rdfpcr (void)
-{
-  unsigned long fpcr;
-  asm ("excb; mf_fpcr %0" : "=f"(fpcr));
-  return fpcr;
-}
-
-
-static inline void
-wrfpcr (unsigned long fpcr)
-{
-  asm volatile ("mt_fpcr %0; excb" : : "f"(fpcr));
-}
+#define convert_bit(M, F, T)           \
+    ((T) < (F)                         \
+     ? ((M) / ((F) / (T))) & (T)       \
+     : ((M) & (F)) * ((T) / (F)))
 
 
 void
 __setfpucw (fpu_control_t fpu_control)
 {
-  unsigned long fpcr = 0, fpcw = 0;
-
-  if (!fpu_control)
-    fpu_control = _FPU_DEFAULT;
-
-  /* first, set dynamic rounding mode: */
-
-  fpcr = rdfpcr();
-  fpcr &= ~FPCR_DYN_MASK;
-  switch (fpu_control & 0xc00)
-    {
-    case _FPU_RC_NEAREST:      fpcr |= FPCR_DYN_NORMAL; break;
-    case _FPU_RC_DOWN:         fpcr |= FPCR_DYN_MINUS; break;
-    case _FPU_RC_UP:           fpcr |= FPCR_DYN_PLUS; break;
-    case _FPU_RC_ZERO:         fpcr |= FPCR_DYN_CHOPPED; break;
-    }
-  wrfpcr(fpcr);
-
-  /* now tell kernel about traps that we like to hear about: */
-
-  fpcw = __ieee_get_fp_control();
-  fpcw &= ~IEEE_TRAP_ENABLE_MASK;
-
-  if (!(fpu_control & _FPU_MASK_IM)) fpcw |= IEEE_TRAP_ENABLE_INV;
-  if (!(fpu_control & _FPU_MASK_DM)) fpcw |= IEEE_TRAP_ENABLE_UNF;
-  if (!(fpu_control & _FPU_MASK_ZM)) fpcw |= IEEE_TRAP_ENABLE_DZE;
-  if (!(fpu_control & _FPU_MASK_OM)) fpcw |= IEEE_TRAP_ENABLE_OVF;
-  if (!(fpu_control & _FPU_MASK_PM)) fpcw |= IEEE_TRAP_ENABLE_INE;
-
-  __fpu_control = fpu_control; /* update global copy */
-
-  __ieee_set_fp_control(fpcw);
+  unsigned long fpcr, swcr, fc = (int)fpu_control;
+
+  /* ??? If this was a real external interface we'd want to read the current
+     exception state with __ieee_get_fp_control.  But this is an internal
+     function only called at process startup, so there's no point in trying
+     to preserve exceptions that cannot have been raised yet.  Indeed, this
+     entire function is likely to be one big nop unless the user overrides
+     the default __fpu_control variable.  */
+
+  /* Convert the rounding mode from fpu_control.h format.  */
+  const unsigned long conv_rnd
+    = (  (FE_TOWARDZERO << (_FPU_RC_ZERO >> 8))
+       | (FE_DOWNWARD << (_FPU_RC_DOWN >> 8))
+       | (FE_TONEAREST << (_FPU_RC_NEAREST >> 8))
+       | (FE_UPWARD << (_FPU_RC_UP >> 8)));
+
+  fpcr = ((conv_rnd >> ((fc >> 8) & 3)) & 3) << FPCR_ROUND_SHIFT;
+
+  /* Convert the exception mask from fpu_control.h format.  */
+  swcr  = convert_bit (~fc, _FPU_MASK_IM, FE_INVALID >> SWCR_ENABLE_SHIFT);
+  swcr |= convert_bit (~fc, _FPU_MASK_DM, FE_UNDERFLOW >> SWCR_ENABLE_SHIFT);
+  swcr |= convert_bit (~fc, _FPU_MASK_ZM, FE_DIVBYZERO >> SWCR_ENABLE_SHIFT);
+  swcr |= convert_bit (~fc, _FPU_MASK_OM, FE_OVERFLOW >> SWCR_ENABLE_SHIFT);
+  swcr |= convert_bit (~fc, _FPU_MASK_PM, FE_INEXACT >> SWCR_ENABLE_SHIFT);
+
+  /* Install everything.  */
+  __fpu_control = fc;
+  asm volatile ("mt_fpcr %0" : : "f"(fpcr));
+  __ieee_set_fp_control(swcr);
 }