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| author | Paul A. Clarke <pc@us.ibm.com> | 2019-09-19 11:18:33 -0500 |
|---|---|---|
| committer | Paul A. Clarke <pc@us.ibm.com> | 2019-09-27 08:50:48 -0500 |
| commit | 7413c188c77adb26a15cf0e98e0a991d09d73c65 (patch) | |
| tree | 5c36d2ff3dcff1e0aab3243b81b1176c18805d87 /sysdeps | |
| parent | e3d85df50b083c9ba68a40f5d45b201cbec4e68b (diff) | |
| download | glibc-7413c188c77adb26a15cf0e98e0a991d09d73c65.zip glibc-7413c188c77adb26a15cf0e98e0a991d09d73c65.tar.gz glibc-7413c188c77adb26a15cf0e98e0a991d09d73c65.tar.bz2 | |
[powerpc] libc_feupdateenv_test: optimize FPSCR access
ROUND_TO_ODD and a couple of other places use libc_feupdateenv_test to
restore the rounding mode and exception enables, preserve exception flags,
and test whether given exception(s) were generated.
If the exception flags haven't changed, then it is sufficient and a bit
more efficient to just restore the rounding mode and enables, rather than
writing the full Floating-Point Status and Control Register (FPSCR).
Reviewed-by: Paul E. Murphy <murphyp@linux.ibm.com>
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/powerpc/fpu/fenv_libc.h | 4 | ||||
| -rw-r--r-- | sysdeps/powerpc/fpu/fenv_private.h | 16 |
2 files changed, 18 insertions, 2 deletions
diff --git a/sysdeps/powerpc/fpu/fenv_libc.h b/sysdeps/powerpc/fpu/fenv_libc.h index bc2684e..d5e4587 100644 --- a/sysdeps/powerpc/fpu/fenv_libc.h +++ b/sysdeps/powerpc/fpu/fenv_libc.h @@ -256,6 +256,10 @@ enum { (FPSCR_VE_MASK|FPSCR_OE_MASK|FPSCR_UE_MASK|FPSCR_ZE_MASK|FPSCR_XE_MASK) #define FPSCR_BASIC_EXCEPTIONS_MASK \ (FPSCR_VX_MASK|FPSCR_OX_MASK|FPSCR_UX_MASK|FPSCR_ZX_MASK|FPSCR_XX_MASK) +#define FPSCR_EXCEPTIONS_MASK (FPSCR_BASIC_EXCEPTIONS_MASK| \ + FPSCR_VXSNAN_MASK|FPSCR_VXISI_MASK|FPSCR_VXIDI_MASK|FPSCR_VXZDZ_MASK| \ + FPSCR_VXIMZ_MASK|FPSCR_VXVC_MASK|FPSCR_VXSOFT_MASK|FPSCR_VXSQRT_MASK| \ + FPSCR_VXCVI_MASK) #define FPSCR_FPRF_MASK \ (FPSCR_FPRF_C_MASK|FPSCR_FPRF_FL_MASK|FPSCR_FPRF_FG_MASK| \ FPSCR_FPRF_FE_MASK|FPSCR_FPRF_FU_MASK) diff --git a/sysdeps/powerpc/fpu/fenv_private.h b/sysdeps/powerpc/fpu/fenv_private.h index 30cbf30..9496026 100644 --- a/sysdeps/powerpc/fpu/fenv_private.h +++ b/sysdeps/powerpc/fpu/fenv_private.h @@ -52,8 +52,20 @@ __libc_femergeenv_ppc (const fenv_t *envp, unsigned long long old_mask, __TEST_AND_EXIT_NON_STOP (old.l, new.l); __TEST_AND_ENTER_NON_STOP (old.l, new.l); - /* Atomically enable and raise (if appropriate) exceptions set in `new'. */ - fesetenv_register (new.fenv); + /* If requesting to keep status, replace control, and merge exceptions, + and exceptions haven't changed, we can just set new control instead + of the whole FPSCR. */ + if ((old_mask & (FPSCR_CONTROL_MASK|FPSCR_STATUS_MASK|FPSCR_EXCEPTIONS_MASK)) + == (FPSCR_STATUS_MASK|FPSCR_EXCEPTIONS_MASK) && + (new_mask & (FPSCR_CONTROL_MASK|FPSCR_STATUS_MASK|FPSCR_EXCEPTIONS_MASK)) + == (FPSCR_CONTROL_MASK|FPSCR_EXCEPTIONS_MASK) && + (old.l & FPSCR_EXCEPTIONS_MASK) == (new.l & FPSCR_EXCEPTIONS_MASK)) + { + fesetenv_mode (new.fenv); + } + else + /* Atomically enable and raise (if appropriate) exceptions set in `new'. */ + fesetenv_register (new.fenv); return old.l; } |