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84d74e427a
glibc/sysdeps/powerpc/fpu/fenv_private.h
Paul Murphy 84d74e427a powerpc: Cleanup fenv_private.h 
Some of the masks are wrong, and the naming is confusing.

There are two basic cases we really care about:

1. Stacking a new rounding mode when running certain
   sections of code, and pausing exception handling.

2. Likewise, but discarding any exceptions which occur
   while running under the new rounding mode.

libc_feholdexcept_setround_ppc_ctx has been removed as it basically
does the same thing as libc_feholdsetround_ppc_ctx but also clearing
any sticky bits.  The restore behavior is what differentiates these
two cases as the SET_RESTORE_ROUND{,_NOEX} macros will either merge
or discard all exceptions occurring during scope of their usage.

Likewise, there are a number of routines to swap, replace,
or merge FP environments.  This change reduces much of
the common and sometimes wrong code.

Tested on ppc64le, with results before and after.
2016-10-21 16:40:03 -02:00

230 lines
7.2 KiB
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/* Private floating point rounding and exceptions handling. PowerPC version.
Copyright (C) 2013-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
#ifndef FENV_PRIVATE_H
#define FENV_PRIVATE_H 1
#include <fenv.h>
#include <fenv_libc.h>
#include <fpu_control.h>
/* Mask for the exception enable bits. */
#define _FPU_ALL_TRAPS (_FPU_MASK_ZM | _FPU_MASK_OM | _FPU_MASK_UM \
| _FPU_MASK_XM | _FPU_MASK_IM)
/* Mask the rounding mode bits. */
#define _FPU_MASK_RN (~0x3)
/* Mask everything but the rounding moded and non-IEEE arithmetic flags. */
#define _FPU_MASK_NOT_RN_NI 0xffffffff00000007LL
/* Mask restore rounding mode and exception enabled. */
#define _FPU_MASK_TRAPS_RN 0xffffffff1fffff00LL
/* Mask exception enable but fraction rounded/inexact and FP result/CC
bits. */
#define _FPU_MASK_FRAC_INEX_RET_CC 0xffffffff1ff80fff
static __always_inline void
__libc_feholdbits_ppc (fenv_t *envp, unsigned long long mask,
unsigned long long bits)
{
fenv_union_t old, new;
old.fenv = *envp = fegetenv_register ();
new.l = (old.l & mask) | bits;
/* If the old env had any 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 & _FPU_ALL_TRAPS) != 0)
(void) __fe_mask_env ();
fesetenv_register (new.fenv);
}
static __always_inline void
libc_feholdexcept_ppc (fenv_t *envp)
{
__libc_feholdbits_ppc (envp, _FPU_MASK_NOT_RN_NI, 0LL);
}
static __always_inline void
libc_feholdexcept_setround_ppc (fenv_t *envp, int r)
{
__libc_feholdbits_ppc (envp, _FPU_MASK_NOT_RN_NI & _FPU_MASK_RN, r);
}
static __always_inline void
libc_fesetround_ppc (int r)
{
__fesetround_inline (r);
}
static __always_inline int
libc_fetestexcept_ppc (int e)
{
fenv_union_t u;
u.fenv = fegetenv_register ();
return u.l & e;
}
static __always_inline void
libc_feholdsetround_ppc (fenv_t *e, int r)
{
__libc_feholdbits_ppc (e, _FPU_MASK_TRAPS_RN, r);
}
static __always_inline unsigned long long
__libc_femergeenv_ppc (const fenv_t *envp, unsigned long long old_mask,
unsigned long long new_mask)
{
fenv_union_t old, new;
new.fenv = *envp;
old.fenv = fegetenv_register ();
/* Merge bits while masking unwanted bits from new and old env. */
new.l = (old.l & old_mask) | (new.l & new_mask);
/* If the old env has no enabled 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 & _FPU_ALL_TRAPS) == 0 && (new.l & _FPU_ALL_TRAPS) != 0)
(void) __fe_nomask_env_priv ();
/* If the old env had any enabled 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 & _FPU_ALL_TRAPS) != 0 && (new.l & _FPU_ALL_TRAPS) == 0)
(void) __fe_mask_env ();
/* Atomically enable and raise (if appropriate) exceptions set in `new'. */
fesetenv_register (new.fenv);
return old.l;
}
static __always_inline void
libc_fesetenv_ppc (const fenv_t *envp)
{
/* Replace the entire environment. */
__libc_femergeenv_ppc (envp, 0LL, -1LL);
}
static __always_inline void
libc_feresetround_ppc (fenv_t *envp)
{
__libc_femergeenv_ppc (envp, _FPU_MASK_TRAPS_RN, _FPU_MASK_FRAC_INEX_RET_CC);
}
static __always_inline int
libc_feupdateenv_test_ppc (fenv_t *envp, int ex)
{
return __libc_femergeenv_ppc (envp, _FPU_MASK_TRAPS_RN,
_FPU_MASK_FRAC_INEX_RET_CC) & ex;
}
static __always_inline void
libc_feupdateenv_ppc (fenv_t *e)
{
libc_feupdateenv_test_ppc (e, 0);
}
#define libc_feholdexceptf libc_feholdexcept_ppc
#define libc_feholdexcept libc_feholdexcept_ppc
#define libc_feholdexcept_setroundf libc_feholdexcept_setround_ppc
#define libc_feholdexcept_setround libc_feholdexcept_setround_ppc
#define libc_fetestexceptf libc_fetestexcept_ppc
#define libc_fetestexcept libc_fetestexcept_ppc
#define libc_fesetroundf libc_fesetround_ppc
#define libc_fesetround libc_fesetround_ppc
#define libc_fesetenvf libc_fesetenv_ppc
#define libc_fesetenv libc_fesetenv_ppc
#define libc_feupdateenv_testf libc_feupdateenv_test_ppc
#define libc_feupdateenv_test libc_feupdateenv_test_ppc
#define libc_feupdateenvf libc_feupdateenv_ppc
#define libc_feupdateenv libc_feupdateenv_ppc
#define libc_feholdsetroundf libc_feholdsetround_ppc
#define libc_feholdsetround libc_feholdsetround_ppc
#define libc_feresetroundf libc_feresetround_ppc
#define libc_feresetround libc_feresetround_ppc
/* We have support for rounding mode context. */
#define HAVE_RM_CTX 1
static __always_inline void
libc_feholdsetround_ppc_ctx (struct rm_ctx *ctx, int r)
{
fenv_union_t old, new;
old.fenv = fegetenv_register ();
new.l = (old.l & _FPU_MASK_TRAPS_RN) | r;
ctx->env = old.fenv;
if (__glibc_unlikely (new.l != old.l))
{
if ((old.l & _FPU_ALL_TRAPS) != 0)
(void) __fe_mask_env ();
fesetenv_register (new.fenv);
ctx->updated_status = true;
}
else
ctx->updated_status = false;
}
static __always_inline void
libc_fesetenv_ppc_ctx (struct rm_ctx *ctx)
{
libc_fesetenv_ppc (&ctx->env);
}
static __always_inline void
libc_feupdateenv_ppc_ctx (struct rm_ctx *ctx)
{
if (__glibc_unlikely (ctx->updated_status))
libc_feresetround_ppc (&ctx->env);
}
static __always_inline void
libc_feresetround_ppc_ctx (struct rm_ctx *ctx)
{
if (__glibc_unlikely (ctx->updated_status))
libc_feresetround_ppc (&ctx->env);
}
#define libc_fesetenv_ctx libc_fesetenv_ppc_ctx
#define libc_fesetenvf_ctx libc_fesetenv_ppc_ctx
#define libc_fesetenvl_ctx libc_fesetenv_ppc_ctx
#define libc_feholdsetround_ctx libc_feholdsetround_ppc_ctx
#define libc_feholdsetroundf_ctx libc_feholdsetround_ppc_ctx
#define libc_feholdsetroundl_ctx libc_feholdsetround_ppc_ctx
#define libc_feresetround_ctx libc_feresetround_ppc_ctx
#define libc_feresetroundf_ctx libc_feresetround_ppc_ctx
#define libc_feresetroundl_ctx libc_feresetround_ppc_ctx
#define libc_feupdateenv_ctx libc_feupdateenv_ppc_ctx
#define libc_feupdateenvf_ctx libc_feupdateenv_ppc_ctx
#define libc_feupdateenvl_ctx libc_feupdateenv_ppc_ctx
#endif
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