diff options
Diffstat (limited to 'sysdeps/powerpc/fpu/feupdateenv.c')
| -rw-r--r-- | sysdeps/powerpc/fpu/feupdateenv.c | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/sysdeps/powerpc/fpu/feupdateenv.c b/sysdeps/powerpc/fpu/feupdateenv.c index 3a60d0f33d..5a4000f599 100644 --- a/sysdeps/powerpc/fpu/feupdateenv.c +++ b/sysdeps/powerpc/fpu/feupdateenv.c @@ -1,5 +1,5 @@ /* Install given floating-point environment and raise exceptions. - Copyright (C) 1997,99,2000,01 Free Software Foundation, Inc. + Copyright (C) 1997,99,2000,01,07 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. @@ -30,8 +30,24 @@ __feupdateenv (const fenv_t *envp) new.fenv = *envp; old.fenv = fegetenv_register (); - /* Copy the set exceptions from `old' to `new'. */ - new.l[1] = (new.l[1] & 0xE00000FF) | (old.l[1] & 0x1FFFFF00); + /* Restore rounding mode and exception enable from *envp and merge + exceptions. Leave fraction rounded/inexact and FP result/CC bits + unchanged. */ + new.l[1] = (old.l[1] & 0x1FFFFF00) | (new.l[1] & 0x1FF80FFF); + + /* If the old env has no eabled exceptions and the new env has any enabled + exceptions, then unmask SIGFPE in the MSR FE0/FE1 bits. This will put + the hardware into "precise mode" and may cause the FPU to run slower on + some hardware. */ + if ((old.l[1] & 0x000000F8) == 0 && (new.l[1] & 0x000000F8) != 0) + (void)__fe_nomask_env (); + + /* If the old env had any eabled exceptions and the new env has no enabled + exceptions, then mask SIGFPE in the MSR FE0/FE1 bits. This may allow the + FPU to run faster because it always takes the default action and can not + generate SIGFPE. */ + if ((old.l[1] & 0x000000F8) != 0 && (new.l[1] & 0x000000F8) == 0) + (void)__fe_mask_env (); /* Atomically enable and raise (if appropriate) exceptions set in `new'. */ fesetenv_register (new.fenv); |