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613c92b3b5
The ldbl-128ibm implementation of nearbyintl uses logic that only works in round-to-nearest mode. This contrasts with rintl, which works in all rounding modes. Now, arguably nearbyintl could simply be aliased to rintl, given that spurious "inexact" is generally allowed for ldbl-128ibm, even for the underlying arithmetic operations. But given that the only point of nearbyintl is to avoid "inexact", this patch follows the more conservative approach of adding conditionals to the rintl implementation to make it suitable for use to implement nearbyintl, then builds it for nearbyintl with USE_AS_NEARBYINTL defined. The test test-nearbyint-except-2 shows up issues when traps on "inexact" are enabled, which turn out to be problems with the powerpc fenv_private.h implementation (two functions that should disable exception traps potentially failing to do so in some cases); this patch duly fixes that as well (I don't see any other existing cases where this would be user-visible; there isn't much use of *_NOEX, *hold* etc. in libm that requires exceptions to be discarded and not trapped on). Tested for powerpc. [BZ #19790] * sysdeps/ieee754/ldbl-128ibm/s_rintl.c [USE_AS_NEARBYINTL] (rintl): Define as macro. [USE_AS_NEARBYINTL] (__rintl): Likewise. (__rintl) [USE_AS_NEARBYINTL]: Use SET_RESTORE_ROUND_NOEX instead of fesetround. Ensure results are evaluated before end of scope. * sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c: Define USE_AS_NEARBYINTL and include s_rintl.c. * sysdeps/powerpc/fpu/fenv_private.h (libc_feholdsetround_ppc): Disable exception traps in new environment. (libc_feholdsetround_ppc_ctx): Likewise.
280 lines
8.6 KiB
C
280 lines
8.6 KiB
C
/* Private floating point rounding and exceptions handling. PowerPC version.
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Copyright (C) 2013-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef FENV_PRIVATE_H
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#define FENV_PRIVATE_H 1
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#include <fenv.h>
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#include <fenv_libc.h>
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#include <fpu_control.h>
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#define _FPU_MASK_ALL (_FPU_MASK_ZM | _FPU_MASK_OM | _FPU_MASK_UM \
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| _FPU_MASK_XM | _FPU_MASK_IM)
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/* Mask everything but the rounding moded and non-IEEE arithmetic flags. */
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#define _FPU_MASK_ROUNDING 0xffffffff00000007LL
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/* Mask restore rounding mode and exception enabled. */
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#define _FPU_MASK_EXCEPT_ROUND 0xffffffff1fffff00LL
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/* Mask exception enable but fraction rounded/inexact and FP result/CC
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bits. */
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#define _FPU_MASK_FRAC_INEX_RET_CC 0x1ff80fff
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static __always_inline void
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libc_feholdexcept_ppc (fenv_t *envp)
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{
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fenv_union_t old, new;
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old.fenv = *envp = fegetenv_register ();
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new.l = old.l & _FPU_MASK_ROUNDING;
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/* If the old env had any enabled exceptions, then mask SIGFPE in the
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MSR FE0/FE1 bits. This may allow the FPU to run faster because it
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always takes the default action and can not generate SIGFPE. */
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if ((old.l & _FPU_MASK_ALL) != 0)
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(void) __fe_mask_env ();
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fesetenv_register (new.fenv);
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}
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static __always_inline void
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libc_fesetround_ppc (int r)
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{
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__fesetround_inline (r);
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}
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static __always_inline void
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libc_feholdexcept_setround_ppc (fenv_t *envp, int r)
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{
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fenv_union_t old, new;
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old.fenv = *envp = fegetenv_register ();
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new.l = (old.l & _FPU_MASK_ROUNDING) | r;
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if ((old.l & _FPU_MASK_ALL) != 0)
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(void) __fe_mask_env ();
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fesetenv_register (new.fenv);
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}
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static __always_inline int
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libc_fetestexcept_ppc (int e)
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{
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fenv_union_t u;
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u.fenv = fegetenv_register ();
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return u.l & e;
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}
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static __always_inline void
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libc_fesetenv_ppc (const fenv_t *envp)
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{
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fenv_union_t old, new;
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new.fenv = *envp;
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old.fenv = fegetenv_register ();
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/* If the old env has no enabled exceptions and the new env has any enabled
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exceptions, then unmask SIGFPE in the MSR FE0/FE1 bits. This will put the
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hardware into "precise mode" and may cause the FPU to run slower on some
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hardware. */
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if ((old.l & _FPU_MASK_ALL) == 0 && (new.l & _FPU_MASK_ALL) != 0)
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(void) __fe_nomask_env_priv ();
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/* If the old env had any enabled exceptions and the new env has no enabled
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exceptions, then mask SIGFPE in the MSR FE0/FE1 bits. This may allow the
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FPU to run faster because it always takes the default action and can not
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generate SIGFPE. */
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if ((old.l & _FPU_MASK_ALL) != 0 && (new.l & _FPU_MASK_ALL) == 0)
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(void) __fe_mask_env ();
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fesetenv_register (*envp);
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}
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static __always_inline int
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libc_feupdateenv_test_ppc (fenv_t *envp, int ex)
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{
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fenv_union_t old, new;
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new.fenv = *envp;
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old.fenv = fegetenv_register ();
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/* Restore rounding mode and exception enable from *envp and merge
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exceptions. Leave fraction rounded/inexact and FP result/CC bits
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unchanged. */
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new.l = (old.l & _FPU_MASK_EXCEPT_ROUND)
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| (new.l & _FPU_MASK_FRAC_INEX_RET_CC);
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if ((old.l & _FPU_MASK_ALL) == 0 && (new.l & _FPU_MASK_ALL) != 0)
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(void) __fe_nomask_env_priv ();
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if ((old.l & _FPU_MASK_ALL) != 0 && (new.l & _FPU_MASK_ALL) == 0)
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(void) __fe_mask_env ();
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fesetenv_register (new.fenv);
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return old.l & ex;
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}
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static __always_inline void
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libc_feupdateenv_ppc (fenv_t *e)
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{
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libc_feupdateenv_test_ppc (e, 0);
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}
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static __always_inline void
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libc_feholdsetround_ppc (fenv_t *e, int r)
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{
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fenv_union_t old, new;
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old.fenv = fegetenv_register ();
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/* Clear current precision and set newer one. */
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new.l = (old.l & ~0x3 & ~_FPU_MASK_ALL) | r;
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*e = old.fenv;
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if ((old.l & _FPU_MASK_ALL) != 0)
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(void) __fe_mask_env ();
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fesetenv_register (new.fenv);
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}
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static __always_inline void
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libc_feresetround_ppc (fenv_t *envp)
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{
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fenv_union_t old, new;
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new.fenv = *envp;
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old.fenv = fegetenv_register ();
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/* Restore rounding mode and exception enable from *envp and merge
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exceptions. Leave fraction rounded/inexact and FP result/CC bits
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unchanged. */
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new.l = (old.l & _FPU_MASK_EXCEPT_ROUND)
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| (new.l & _FPU_MASK_FRAC_INEX_RET_CC);
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if ((old.l & _FPU_MASK_ALL) == 0 && (new.l & _FPU_MASK_ALL) != 0)
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(void) __fe_nomask_env_priv ();
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if ((old.l & _FPU_MASK_ALL) != 0 && (new.l & _FPU_MASK_ALL) == 0)
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(void) __fe_mask_env ();
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/* Atomically enable and raise (if appropriate) exceptions set in `new'. */
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fesetenv_register (new.fenv);
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}
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#define libc_feholdexceptf libc_feholdexcept_ppc
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#define libc_feholdexcept libc_feholdexcept_ppc
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#define libc_feholdexcept_setroundf libc_feholdexcept_setround_ppc
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#define libc_feholdexcept_setround libc_feholdexcept_setround_ppc
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#define libc_fetestexceptf libc_fetestexcept_ppc
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#define libc_fetestexcept libc_fetestexcept_ppc
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#define libc_fesetroundf libc_fesetround_ppc
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#define libc_fesetround libc_fesetround_ppc
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#define libc_fesetenvf libc_fesetenv_ppc
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#define libc_fesetenv libc_fesetenv_ppc
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#define libc_feupdateenv_testf libc_feupdateenv_test_ppc
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#define libc_feupdateenv_test libc_feupdateenv_test_ppc
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#define libc_feupdateenvf libc_feupdateenv_ppc
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#define libc_feupdateenv libc_feupdateenv_ppc
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#define libc_feholdsetroundf libc_feholdsetround_ppc
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#define libc_feholdsetround libc_feholdsetround_ppc
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#define libc_feresetroundf libc_feresetround_ppc
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#define libc_feresetround libc_feresetround_ppc
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/* We have support for rounding mode context. */
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#define HAVE_RM_CTX 1
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static __always_inline void
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libc_feholdexcept_setround_ppc_ctx (struct rm_ctx *ctx, int r)
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{
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fenv_union_t old, new;
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old.fenv = fegetenv_register ();
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new.l = (old.l & _FPU_MASK_ROUNDING) | r;
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ctx->env = old.fenv;
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if (__glibc_unlikely (new.l != old.l))
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{
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if ((old.l & _FPU_MASK_ALL) != 0)
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(void) __fe_mask_env ();
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fesetenv_register (new.fenv);
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ctx->updated_status = true;
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}
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else
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ctx->updated_status = false;
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}
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static __always_inline void
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libc_fesetenv_ppc_ctx (struct rm_ctx *ctx)
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{
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libc_fesetenv_ppc (&ctx->env);
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}
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static __always_inline void
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libc_feupdateenv_ppc_ctx (struct rm_ctx *ctx)
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{
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if (__glibc_unlikely (ctx->updated_status))
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libc_feupdateenv_test_ppc (&ctx->env, 0);
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}
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static __always_inline void
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libc_feholdsetround_ppc_ctx (struct rm_ctx *ctx, int r)
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{
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fenv_union_t old, new;
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old.fenv = fegetenv_register ();
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new.l = (old.l & ~0x3 & ~_FPU_MASK_ALL) | r;
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ctx->env = old.fenv;
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if (__glibc_unlikely (new.l != old.l))
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{
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if ((old.l & _FPU_MASK_ALL) != 0)
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(void) __fe_mask_env ();
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fesetenv_register (new.fenv);
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ctx->updated_status = true;
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}
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else
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ctx->updated_status = false;
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}
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static __always_inline void
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libc_feresetround_ppc_ctx (struct rm_ctx *ctx)
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{
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if (__glibc_unlikely (ctx->updated_status))
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libc_feresetround_ppc (&ctx->env);
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}
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#define libc_feholdexcept_setround_ctx libc_feholdexcept_setround_ppc_ctx
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#define libc_feholdexcept_setroundf_ctx libc_feholdexcept_setround_ppc_ctx
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#define libc_feholdexcept_setroundl_ctx libc_feholdexcept_setround_ppc_ctx
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#define libc_fesetenv_ctx libc_fesetenv_ppc_ctx
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#define libc_fesetenvf_ctx libc_fesetenv_ppc_ctx
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#define libc_fesetenvl_ctx libc_fesetenv_ppc_ctx
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#define libc_feholdsetround_ctx libc_feholdsetround_ppc_ctx
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#define libc_feholdsetroundf_ctx libc_feholdsetround_ppc_ctx
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#define libc_feholdsetroundl_ctx libc_feholdsetround_ppc_ctx
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#define libc_feresetround_ctx libc_feresetround_ppc_ctx
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#define libc_feresetroundf_ctx libc_feresetround_ppc_ctx
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#define libc_feresetroundl_ctx libc_feresetround_ppc_ctx
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#define libc_feupdateenv_ctx libc_feupdateenv_ppc_ctx
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#define libc_feupdateenvf_ctx libc_feupdateenv_ppc_ctx
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#define libc_feupdateenvl_ctx libc_feupdateenv_ppc_ctx
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#endif
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