From: Paul A. Clarke Date: Thu, 19 Sep 2019 16:18:33 +0000 (-0500) Subject: [powerpc] libc_feupdateenv_test: optimize FPSCR access X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=11c0fd3ab34a06dd0faf401daecd07911414eb24;p=thirdparty%2Fglibc.git [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 --- diff --git a/ChangeLog b/ChangeLog index 7a633d7052f..5fde58a2982 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2019-09-27 Paul A. Clarke + + * sysdeps/powerpc/fpu/fenv_libc.h (FPSCR_EXCEPTIONS_MASK): New. + * sysdeps/powerpc/fpu/fenv_private.h (__libc_femergeenv_ppc): Optimize + to write FPSCR control only, if exceptions have not changed. + 2019-09-27 Paul A. Clarke * sysdeps/powerpc/fpu/fenv_libc.h: diff --git a/sysdeps/powerpc/fpu/fenv_libc.h b/sysdeps/powerpc/fpu/fenv_libc.h index 9163fb624cb..38ab6cd3cb9 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 0036cca1cf7..d0805534fd5 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; }