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[PATCH 2/2] ARM: Improve fenv implementation
- From: "Wilco" <wdijkstr at arm dot com>
- To: <libc-alpha at sourceware dot org>
- Date: Tue, 25 Mar 2014 18:46:03 -0000
- Subject: [PATCH 2/2] ARM: Improve fenv implementation
- Authentication-results: sourceware.org; auth=none
Hi,
The second patch improves the fenv implementation by using the inline functions from fenv_private
where possible rather than duplicating functionality. The remaining functions are optimized in a
similar way to avoid unnecessary FPSCR writes.
OK for commit?
Wilco
---
sysdeps/arm/fclrexcpt.c | 12 ++++++------
sysdeps/arm/fedisblxcpt.c | 4 +++-
sysdeps/arm/feenablxcpt.c | 10 +++++-----
sysdeps/arm/fegetround.c | 14 ++------------
sysdeps/arm/feholdexcpt.c | 16 ++--------------
sysdeps/arm/fesetenv.c | 44 ++++++++++++++++++++++----------------------
sysdeps/arm/fesetround.c | 10 ++--------
sysdeps/arm/feupdateenv.c | 26 +++++++++++++++++---------
sysdeps/arm/fgetexcptflg.c | 9 ++-------
sysdeps/arm/fsetexcptflg.c | 13 ++++++++-----
sysdeps/arm/ftestexcept.c | 11 +++--------
sysdeps/arm/setfpucw.c | 11 ++++++-----
12 files changed, 78 insertions(+), 102 deletions(-)
diff --git a/sysdeps/arm/fclrexcpt.c b/sysdeps/arm/fclrexcpt.c
index 1453192..824145e 100644
--- a/sysdeps/arm/fclrexcpt.c
+++ b/sysdeps/arm/fclrexcpt.c
@@ -24,19 +24,19 @@
int
__feclearexcept (int excepts)
{
- fpu_control_t fpscr;
+ fpu_control_t fpscr, new_fpscr;
/* Fail if a VFP unit isn't present unless nothing needs to be done. */
if (!ARM_HAVE_VFP)
- return (excepts != 0);
+ return (excepts != 0);
_FPU_GETCW (fpscr);
excepts &= FE_ALL_EXCEPT;
+ new_fpscr = fpscr & ~excepts;
- /* Clear the relevant bits. */
- fpscr = (fpscr & ~FE_ALL_EXCEPT) | (fpscr & FE_ALL_EXCEPT & ~excepts);
-
- _FPU_SETCW (fpscr);
+ /* Write new exception flags if changed. */
+ if (new_fpscr != fpscr)
+ _FPU_SETCW (new_fpscr);
return 0;
}
diff --git a/sysdeps/arm/fedisblxcpt.c b/sysdeps/arm/fedisblxcpt.c
index f2956cd..80f5a44 100644
--- a/sysdeps/arm/fedisblxcpt.c
+++ b/sysdeps/arm/fedisblxcpt.c
@@ -35,7 +35,9 @@ fedisableexcept (int excepts)
excepts &= FE_ALL_EXCEPT;
new_fpscr = fpscr & ~(excepts << FE_EXCEPT_SHIFT);
- _FPU_SETCW (new_fpscr);
+ /* Write new exceptions if changed. */
+ if (__glibc_unlikely (new_fpscr != 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 afd8943..e649b2f 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);
- _FPU_SETCW (new_fpscr);
-
- if (excepts != 0)
+ if (new_fpscr != fpscr)
{
+ _FPU_SETCW (new_fpscr);
+
/* 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 & (excepts << FE_EXCEPT_SHIFT))
- != (excepts << FE_EXCEPT_SHIFT))
+
+ if (((new_fpscr >> FE_EXCEPT_SHIFT) & excepts) != excepts)
return -1;
}
diff --git a/sysdeps/arm/fegetround.c b/sysdeps/arm/fegetround.c
index 1c9c151..fbad0b3 100644
--- a/sysdeps/arm/fegetround.c
+++ b/sysdeps/arm/fegetround.c
@@ -16,22 +16,12 @@
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
-#include <fenv.h>
-#include <fpu_control.h>
-#include <arm-features.h>
+#include <get-rounding-mode.h>
int
fegetround (void)
{
- 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;
+ return get_rounding_mode ();
}
libm_hidden_def (fegetround)
diff --git a/sysdeps/arm/feholdexcpt.c b/sysdeps/arm/feholdexcpt.c
index 258ba66..2d79e0c 100644
--- a/sysdeps/arm/feholdexcpt.c
+++ b/sysdeps/arm/feholdexcpt.c
@@ -16,30 +16,18 @@
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
-#include <fenv.h>
-#include <fpu_control.h>
+#include <fenv_private.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;
- _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);
+ libc_feholdexcept_vfp (envp);
return 0;
}
diff --git a/sysdeps/arm/fesetenv.c b/sysdeps/arm/fesetenv.c
index 43b9b47..de95182 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.h>
-#include <fpu_control.h>
+#include <fenv_private.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;
+ return 1;
+
+ if (__glibc_unlikely ((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. */
- fpscr &= _FPU_RESERVED;
+ /* Preserve the reserved FPSCR flags. */
+ new_fpscr = fpscr & _FPU_RESERVED;
- if (envp == FE_DFL_ENV)
- fpscr |= _FPU_DEFAULT;
- else if (envp == FE_NOMASK_ENV)
- fpscr |= _FPU_IEEE;
- else
- fpscr |= envp->__cw & ~_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);
- _FPU_SETCW (fpscr);
+ if ((fpscr & _FPU_IEEE) != _FPU_IEEE)
+ return 1;
+ }
- 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;
+ return 0;
}
+ libc_fesetenv_vfp (envp);
return 0;
}
diff --git a/sysdeps/arm/fesetround.c b/sysdeps/arm/fesetround.c
index d1b92dc..f52c50a 100644
--- a/sysdeps/arm/fesetround.c
+++ b/sysdeps/arm/fesetround.c
@@ -16,28 +16,22 @@
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
-#include <fenv.h>
-#include <fpu_control.h>
+#include <fenv_private.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;
- _FPU_GETCW (fpscr);
- fpscr = (fpscr & ~FE_TOWARDZERO) | round;
- _FPU_SETCW (fpscr);
+ libc_fesetround_vfp (round);
return 0;
}
diff --git a/sysdeps/arm/feupdateenv.c b/sysdeps/arm/feupdateenv.c
index 7cf6206..9c42dea 100644
--- a/sysdeps/arm/feupdateenv.c
+++ b/sysdeps/arm/feupdateenv.c
@@ -17,27 +17,35 @@
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
-#include <fenv.h>
-#include <fpu_control.h>
+#include <fenv_private.h>
#include <arm-features.h>
int
__feupdateenv (const fenv_t *envp)
{
- fpu_control_t fpscr;
+ fenv_t fenv;
/* Fail if a VFP unit isn't present. */
if (!ARM_HAVE_VFP)
- return 1;
+ return 1;
- _FPU_GETCW (fpscr);
+ if (__glibc_unlikely ((envp == FE_DFL_ENV) || (envp == FE_NOMASK_ENV)))
+ {
+ fpu_control_t fpscr;
- /* Install new environment. */
- fesetenv (envp);
+ _FPU_GETCW (fpscr);
- /* Raise the saved exceptions. */
- feraiseexcept (fpscr & FE_ALL_EXCEPT);
+ /* 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);
return 0;
}
diff --git a/sysdeps/arm/fgetexcptflg.c b/sysdeps/arm/fgetexcptflg.c
index e1eb420..19c8b6d 100644
--- a/sysdeps/arm/fgetexcptflg.c
+++ b/sysdeps/arm/fgetexcptflg.c
@@ -17,23 +17,18 @@
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
-#include <fenv.h>
-#include <fpu_control.h>
+#include <fenv_private.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;
- _FPU_GETCW (fpscr);
-
- *flagp = fpscr & excepts & FE_ALL_EXCEPT;
+ *flagp = libc_fetestexcept_vfp (excepts);
return 0;
}
diff --git a/sysdeps/arm/fsetexcptflg.c b/sysdeps/arm/fsetexcptflg.c
index a594e15..c1a6c1a 100644
--- a/sysdeps/arm/fsetexcptflg.c
+++ b/sysdeps/arm/fsetexcptflg.c
@@ -25,20 +25,23 @@
int
__fesetexceptflag (const fexcept_t *flagp, int excepts)
{
- fpu_control_t fpscr;
+ fpu_control_t fpscr, new_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. */
- fpscr &= ~(excepts & FE_ALL_EXCEPT);
- fpscr |= (*flagp & excepts & FE_ALL_EXCEPT);
+ new_fpscr = fpscr & ~excepts;
+ new_fpscr |= *flagp & excepts;
+
+ /* Write new exception flags if changed. */
+ if (new_fpscr != fpscr)
+ _FPU_SETCW (new_fpscr);
- /* Save state back to the FPU. */
- _FPU_SETCW (fpscr);
return 0;
}
diff --git a/sysdeps/arm/ftestexcept.c b/sysdeps/arm/ftestexcept.c
index de082b2..6c5d3a8 100644
--- a/sysdeps/arm/ftestexcept.c
+++ b/sysdeps/arm/ftestexcept.c
@@ -16,23 +16,18 @@
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
-#include <fenv.h>
-#include <fpu_control.h>
+#include <fenv_private.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;
- /* Get current exceptions. */
- _FPU_GETCW (fpscr);
-
- return fpscr & excepts & FE_ALL_EXCEPT;
+ return libc_fetestexcept_vfp (excepts);
}
+
libm_hidden_def (fetestexcept)
diff --git a/sysdeps/arm/setfpucw.c b/sysdeps/arm/setfpucw.c
index 7416377..259b020 100644
--- a/sysdeps/arm/setfpucw.c
+++ b/sysdeps/arm/setfpucw.c
@@ -24,19 +24,20 @@
void
__setfpucw (fpu_control_t set)
{
- fpu_control_t fpscr;
+ fpu_control_t fpscr, new_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). */
- fpscr &= _FPU_RESERVED;
- fpscr |= set & ~_FPU_RESERVED;
+ new_fpscr = fpscr & _FPU_RESERVED;
+ new_fpscr |= set & ~_FPU_RESERVED;
- _FPU_SETCW (fpscr);
+ /* Write FPSCR if changed. */
+ if (new_fpscr != fpscr)
+ _FPU_SETCW (fpscr);
}
--
1.7.9.5