Revert "ARM: Improve fenv implementation"

This reverts commit c0c08d02c82275353f5c556f935a1a01714d9d7f.

13 files changed, 99 insertions, 93 deletions

diff --git a/ChangeLog b/ChangeLog
index c606b0d5cd..0a9a26584d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1013,24 +1013,6 @@
 
 2014-05-14  Wilco  <wdijkstr@arm.com>
 
-	* sysdeps/arm/fclrexcpt.c: Optimize to avoid unnecessary FPSCR writes.
-	* sysdeps/arm/fedisblxcpt.c: Likewise.
-	* sysdeps/arm/feenablxcpt.c: Likewise.
-	* sysdeps/arm/fegetround.c: Call (get_rounding_mode).
-	* sysdeps/arm/feholdexcpt.c: Call optimized (libc_feholdexcept_vfp).
-	* sysdeps/arm/fesetenv.c: Special case FE_DFL_ENV and FE_NOMASK_ENV.
-	Call optimized (libc_fesetenv_vfp).
-	* sysdeps/arm/fesetround.c: Call optimized (libc_fesetround_vfp).
-	* sysdeps/arm/feupdateenv.c: Special case FE_DFL_ENV and FE_NOMASK_ENV.
-	Call optimized (libc_feupdateenv_vfp).
-	* sysdeps/arm/fgetexcptflg.c: Call optimized (libc_fetestexcept_vfp).
-	* sysdeps/arm/fsetexcptflg.c: Optimize to avoid unnecessary FPSCR
-	writes.
-	* sysdeps/arm/ftestexcept.c: Call optimized (libc_fetestexcept_vfp).
-	* sysdeps/arm/setfpucw.c: Optimize to avoid unnecessary FPSCR writes.
-
-2014-05-14  Wilco  <wdijkstr@arm.com>
-
 	* sysdeps/arm/fclrexcpt.c: Cleanup.
 	* sysdeps/arm/fedisblxcpt.c: Cleanup.
 	* sysdeps/arm/feenablxcpt.c: Cleanup.
diff --git a/sysdeps/arm/fclrexcpt.c b/sysdeps/arm/fclrexcpt.c
index 31420ed3c7..cbf61a6f4a 100644
--- a/sysdeps/arm/fclrexcpt.c
+++ b/sysdeps/arm/fclrexcpt.c
@@ -24,7 +24,7 @@
 int
 feclearexcept (int excepts)
 {
-  fpu_control_t fpscr, new_fpscr;
+  fpu_control_t fpscr;
 
   /* Fail if a VFP unit isn't present unless nothing needs to be done.  */
   if (!ARM_HAVE_VFP)
@@ -32,11 +32,11 @@ feclearexcept (int excepts)
 
   _FPU_GETCW (fpscr);
   excepts &= FE_ALL_EXCEPT;
-  new_fpscr = fpscr & ~excepts;
 
-  /* Write new exception flags if changed.  */
-  if (new_fpscr != fpscr)
-    _FPU_SETCW (new_fpscr);
+  /* Clear the relevant bits.  */
+  fpscr = (fpscr & ~FE_ALL_EXCEPT) | (fpscr & FE_ALL_EXCEPT & ~excepts);
+
+  _FPU_SETCW (fpscr);
 
   return 0;
 }
diff --git a/sysdeps/arm/fedisblxcpt.c b/sysdeps/arm/fedisblxcpt.c
index d5e0f0031a..f2956cd32a 100644
--- a/sysdeps/arm/fedisblxcpt.c
+++ b/sysdeps/arm/fedisblxcpt.c
@@ -35,9 +35,7 @@ fedisableexcept (int excepts)
   excepts &= FE_ALL_EXCEPT;
   new_fpscr = fpscr & ~(excepts << FE_EXCEPT_SHIFT);
 
-  /* Write new exceptions if changed.  */
-  if (new_fpscr != fpscr)
-    _FPU_SETCW (new_fpscr);
+  _FPU_SETCW (new_fpscr);
 
   return (fpscr >> FE_EXCEPT_SHIFT) & FE_ALL_EXCEPT;
 }
diff --git a/sysdeps/arm/feenablxcpt.c b/sysdeps/arm/feenablxcpt.c
index e649b2f1e1..afd8943638 100644
--- a/sysdeps/arm/feenablxcpt.c
+++ b/sysdeps/arm/feenablxcpt.c
@@ -35,15 +35,15 @@ feenableexcept (int excepts)
   excepts &= FE_ALL_EXCEPT;
   new_fpscr = fpscr | (excepts << FE_EXCEPT_SHIFT);
 
-  if (new_fpscr != fpscr)
-    {
-      _FPU_SETCW (new_fpscr);
+  _FPU_SETCW (new_fpscr);
 
+  if (excepts != 0)
+    {
       /* Not all VFP architectures support trapping exceptions, so
 	 test whether the relevant bits were set and fail if not.  */
       _FPU_GETCW (new_fpscr);
-
-      if (((new_fpscr >> FE_EXCEPT_SHIFT) & excepts) != excepts)
+      if ((new_fpscr & (excepts << FE_EXCEPT_SHIFT))
+	  != (excepts << FE_EXCEPT_SHIFT))
 	return -1;
     }
 
diff --git a/sysdeps/arm/fegetround.c b/sysdeps/arm/fegetround.c
index fbad0b3078..1c9c151a16 100644
--- a/sysdeps/arm/fegetround.c
+++ b/sysdeps/arm/fegetround.c
@@ -16,12 +16,22 @@
    License along with the GNU C Library.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <get-rounding-mode.h>
+#include <fenv.h>
+#include <fpu_control.h>
+#include <arm-features.h>
 
 
 int
 fegetround (void)
 {
-  return get_rounding_mode ();
+  fpu_control_t fpscr;
+
+  /* FE_TONEAREST is the only supported rounding mode
+     if a VFP unit isn't present.  */
+  if (!ARM_HAVE_VFP)
+    return FE_TONEAREST;
+
+  _FPU_GETCW (fpscr);
+  return fpscr & FE_TOWARDZERO;
 }
 libm_hidden_def (fegetround)
diff --git a/sysdeps/arm/feholdexcpt.c b/sysdeps/arm/feholdexcpt.c
index 2d79e0c46d..258ba6637f 100644
--- a/sysdeps/arm/feholdexcpt.c
+++ b/sysdeps/arm/feholdexcpt.c
@@ -16,18 +16,30 @@
    License along with the GNU C Library.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <fenv_private.h>
+#include <fenv.h>
+#include <fpu_control.h>
 #include <arm-features.h>
 
 
 int
 feholdexcept (fenv_t *envp)
 {
+  fpu_control_t fpscr;
+
   /* Fail if a VFP unit isn't present.  */
   if (!ARM_HAVE_VFP)
     return 1;
 
-  libc_feholdexcept_vfp (envp);
+  _FPU_GETCW (fpscr);
+  envp->__cw = fpscr;
+
+  /* Now set all exceptions to non-stop.  */
+  fpscr &= ~(FE_ALL_EXCEPT << FE_EXCEPT_SHIFT);
+
+  /* And clear all exception flags.  */
+  fpscr &= ~FE_ALL_EXCEPT;
+
+  _FPU_SETCW (fpscr);
   return 0;
 }
 
diff --git a/sysdeps/arm/fesetenv.c b/sysdeps/arm/fesetenv.c
index 9e2aa81f9b..62031d596d 100644
--- a/sysdeps/arm/fesetenv.c
+++ b/sysdeps/arm/fesetenv.c
@@ -16,43 +16,43 @@
    License along with the GNU C Library.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <fenv_private.h>
+#include <fenv.h>
+#include <fpu_control.h>
 #include <arm-features.h>
 
 
 int
 fesetenv (const fenv_t *envp)
 {
+  fpu_control_t fpscr;
+
   /* Fail if a VFP unit isn't present.  */
   if (!ARM_HAVE_VFP)
     return 1;
 
-  if ((envp == FE_DFL_ENV) || (envp == FE_NOMASK_ENV))
-    {
-      fpu_control_t fpscr, new_fpscr;
-
-      _FPU_GETCW (fpscr);
+  _FPU_GETCW (fpscr);
 
-      /* Preserve the reserved FPSCR flags.  */
-      new_fpscr = fpscr & _FPU_RESERVED;
+  /* Preserve the reserved FPSCR flags.  */
+  fpscr &= _FPU_RESERVED;
 
-      if (envp == FE_DFL_ENV)
-	_FPU_SETCW (new_fpscr | _FPU_DEFAULT);
-      else
-	{
-	  _FPU_SETCW (new_fpscr | _FPU_IEEE);
-	  /* Not all VFP architectures support trapping exceptions, so
-	     test whether the relevant bits were set and fail if not.  */
-	  _FPU_GETCW (fpscr);
+  if (envp == FE_DFL_ENV)
+    fpscr |= _FPU_DEFAULT;
+  else if (envp == FE_NOMASK_ENV)
+    fpscr |= _FPU_IEEE;
+  else
+    fpscr |= envp->__cw & ~_FPU_RESERVED;
 
-	  if ((fpscr & _FPU_IEEE) != _FPU_IEEE)
-	    return 1;
-	}
+  _FPU_SETCW (fpscr);
 
-      return 0;
+  if (envp == FE_NOMASK_ENV)
+    {
+      /* Not all VFP architectures support trapping exceptions, so
+	 test whether the relevant bits were set and fail if not.  */
+      _FPU_GETCW (fpscr);
+      if ((fpscr & _FPU_IEEE) != _FPU_IEEE)
+	return 1;
     }
 
-  libc_fesetenv_vfp (envp);
   return 0;
 }
 
diff --git a/sysdeps/arm/fesetround.c b/sysdeps/arm/fesetround.c
index f52c50aec4..d1b92dc255 100644
--- a/sysdeps/arm/fesetround.c
+++ b/sysdeps/arm/fesetround.c
@@ -16,22 +16,28 @@
    License along with the GNU C Library.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <fenv_private.h>
+#include <fenv.h>
+#include <fpu_control.h>
 #include <arm-features.h>
 
 
 int
 fesetround (int round)
 {
+  fpu_control_t fpscr;
+
   /* FE_TONEAREST is the only supported rounding mode
      if a VFP unit isn't present.  */
   if (!ARM_HAVE_VFP)
     return (round == FE_TONEAREST) ? 0 : 1;
 
+  /* Fail if the rounding mode is not valid.  */
   if (round & ~FE_TOWARDZERO)
     return 1;
 
-  libc_fesetround_vfp (round);
+  _FPU_GETCW (fpscr);
+  fpscr = (fpscr & ~FE_TOWARDZERO) | round;
+  _FPU_SETCW (fpscr);
   return 0;
 }
 
diff --git a/sysdeps/arm/feupdateenv.c b/sysdeps/arm/feupdateenv.c
index 2a7b3ec894..55a15025c6 100644
--- a/sysdeps/arm/feupdateenv.c
+++ b/sysdeps/arm/feupdateenv.c
@@ -17,35 +17,27 @@
    License along with the GNU C Library.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <fenv_private.h>
+#include <fenv.h>
+#include <fpu_control.h>
 #include <arm-features.h>
 
 
 int
 feupdateenv (const fenv_t *envp)
 {
-  fenv_t fenv;
+  fpu_control_t fpscr;
 
   /* Fail if a VFP unit isn't present.  */
   if (!ARM_HAVE_VFP)
     return 1;
 
-  if ((envp == FE_DFL_ENV) || (envp == FE_NOMASK_ENV))
-    {
-      fpu_control_t fpscr;
+  _FPU_GETCW (fpscr);
 
-      _FPU_GETCW (fpscr);
+  /* Install new environment.  */
+  fesetenv (envp);
 
-      /* Preserve the reserved FPSCR flags.  */
-      fpscr &= _FPU_RESERVED;
-      fpscr |= (envp == FE_DFL_ENV) ? _FPU_DEFAULT : _FPU_IEEE;
-
-      /* Create a valid fenv to pass to libc_feupdateenv_vfp.  */
-      fenv.__cw = fpscr;
-      envp = &fenv;
-    }
-
-  libc_feupdateenv_vfp (envp);
+  /* Raise the saved exceptions.  */
+  feraiseexcept (fpscr & FE_ALL_EXCEPT);
   return 0;
 }
 libm_hidden_def (feupdateenv)
diff --git a/sysdeps/arm/fgetexcptflg.c b/sysdeps/arm/fgetexcptflg.c
index 994555ca19..63fdfbf747 100644
--- a/sysdeps/arm/fgetexcptflg.c
+++ b/sysdeps/arm/fgetexcptflg.c
@@ -17,17 +17,22 @@
    License along with the GNU C Library.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <fenv_private.h>
+#include <fenv.h>
+#include <fpu_control.h>
 #include <arm-features.h>
 
 
 int
 fegetexceptflag (fexcept_t *flagp, int excepts)
 {
+  fpu_control_t fpscr;
+
   /* Fail if a VFP unit isn't present.  */
   if (!ARM_HAVE_VFP)
     return 1;
 
-  *flagp = libc_fetestexcept_vfp (excepts);
+  _FPU_GETCW (fpscr);
+
+  *flagp = fpscr & excepts & FE_ALL_EXCEPT;
   return 0;
 }
diff --git a/sysdeps/arm/fsetexcptflg.c b/sysdeps/arm/fsetexcptflg.c
index 28810d3ec8..1a610ff912 100644
--- a/sysdeps/arm/fsetexcptflg.c
+++ b/sysdeps/arm/fsetexcptflg.c
@@ -25,22 +25,19 @@
 int
 fesetexceptflag (const fexcept_t *flagp, int excepts)
 {
-  fpu_control_t fpscr, new_fpscr;
+  fpu_control_t fpscr;
 
   /* Fail if a VFP unit isn't present unless nothing needs to be done.  */
   if (!ARM_HAVE_VFP)
     return (excepts != 0);
 
   _FPU_GETCW (fpscr);
-  excepts &= FE_ALL_EXCEPT;
 
   /* Set the desired exception mask.  */
-  new_fpscr = fpscr & ~excepts;
-  new_fpscr |= *flagp & excepts;
-
-  /* Write new exception flags if changed.  */
-  if (new_fpscr != fpscr)
-    _FPU_SETCW (new_fpscr);
+  fpscr &= ~(excepts & FE_ALL_EXCEPT);
+  fpscr |= (*flagp & excepts & FE_ALL_EXCEPT);
 
+  /* Save state back to the FPU.  */
+  _FPU_SETCW (fpscr);
   return 0;
 }
diff --git a/sysdeps/arm/ftestexcept.c b/sysdeps/arm/ftestexcept.c
index 6c5d3a8288..de082b281a 100644
--- a/sysdeps/arm/ftestexcept.c
+++ b/sysdeps/arm/ftestexcept.c
@@ -16,18 +16,23 @@
    License along with the GNU C Library.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <fenv_private.h>
+#include <fenv.h>
+#include <fpu_control.h>
 #include <arm-features.h>
 
 
 int
 fetestexcept (int excepts)
 {
+  fpu_control_t fpscr;
+
   /* Return no exception flags if a VFP unit isn't present.  */
   if (!ARM_HAVE_VFP)
     return 0;
 
-  return libc_fetestexcept_vfp (excepts);
-}
+  /* Get current exceptions.  */
+  _FPU_GETCW (fpscr);
 
+  return fpscr & excepts & FE_ALL_EXCEPT;
+}
 libm_hidden_def (fetestexcept)
diff --git a/sysdeps/arm/setfpucw.c b/sysdeps/arm/setfpucw.c
index 259b020f81..7416377f9e 100644
--- a/sysdeps/arm/setfpucw.c
+++ b/sysdeps/arm/setfpucw.c
@@ -24,20 +24,19 @@
 void
 __setfpucw (fpu_control_t set)
 {
-  fpu_control_t fpscr, new_fpscr;
+  fpu_control_t fpscr;
 
   /* Do nothing if a VFP unit isn't present.  */
   if (!ARM_HAVE_VFP)
     return;
 
+  /* Fetch the current control word.  */
   _FPU_GETCW (fpscr);
 
   /* Preserve the reserved bits, and set the rest as the user
      specified (or the default, if the user gave zero).  */
-  new_fpscr = fpscr & _FPU_RESERVED;
-  new_fpscr |= set & ~_FPU_RESERVED;
+  fpscr &= _FPU_RESERVED;
+  fpscr |= set & ~_FPU_RESERVED;
 
-  /* Write FPSCR if changed.  */
-  if (new_fpscr != fpscr)
-    _FPU_SETCW (fpscr);
+  _FPU_SETCW (fpscr);
 }