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| author | Wilco <wdijkstr@arm.com> | 2014-06-24 12:04:27 +0000 |
|---|---|---|
| committer | Wilco <wdijkstr@arm.com> | 2014-06-24 12:04:27 +0000 |
| commit | 001f7b773c637560ecfa686452a5e68d60d07db3 (patch) | |
| tree | 08bd670c6b892304a287c56f6cbeb00e92276567 /sysdeps/arm/fsetexcptflg.c | |
| parent | 4841e6a6c2fa691201fb52dfaf6b6a8920229bac (diff) | |
| download | glibc-001f7b773c637560ecfa686452a5e68d60d07db3.zip glibc-001f7b773c637560ecfa686452a5e68d60d07db3.tar.gz glibc-001f7b773c637560ecfa686452a5e68d60d07db3.tar.bz2 | |
Speed up the ARM fenv implementation by avoiding unnecessary FPSCR
writes if the FPSCR remains unchanged.
2014-06-24 Wilco <wdijkstr@arm.com>
* sysdeps/arm/fclrexcpt.c (feclearexcept):
Optimize to avoid unnecessary FPSCR writes.
* sysdeps/arm/fedisblxcpt.c (fedisableexcept): Likewise.
* sysdeps/arm/feenablxcpt.c (feenableexcept): Likewise.
* sysdeps/arm/fsetexcptflg.c (fesetexceptflag): Likewise.
* sysdeps/arm/setfpucw.c (__setfpucw): Likewise.
Diffstat (limited to 'sysdeps/arm/fsetexcptflg.c')
| -rw-r--r-- | sysdeps/arm/fsetexcptflg.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/sysdeps/arm/fsetexcptflg.c b/sysdeps/arm/fsetexcptflg.c index 1a610ff..28810d3 100644 --- a/sysdeps/arm/fsetexcptflg.c +++ b/sysdeps/arm/fsetexcptflg.c @@ -25,19 +25,22 @@ 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; } |