glibc/sysdeps/powerpc/fpu/fenv_private.h
Paul A. Clarke 36c17c7079 [powerpc] libc_feholdsetround_noex_ppc_ctx: optimize FPSCR write
libc_feholdsetround_noex_ppc_ctx currently performs:
1. Read FPSCR, save to context.
2. Create new FPSCR value: clear enables and set new rounding mode.
3. Write new value to FPSCR.

Since other bits just pass through, there is no need to write them.

Instead, write just the changed values (enables and rounding mode),
which can be a bit more efficient.
2019-09-27 11:01:54 -05:00

191 lines
6.2 KiB
C

/* Private floating point rounding and exceptions handling. PowerPC version.
Copyright (C) 2013-2019 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
<https://www.gnu.org/licenses/>. */
#ifndef POWERPC_FENV_PRIVATE_H
#define POWERPC_FENV_PRIVATE_H 1
#include <fenv.h>
#include <fenv_libc.h>
#include <fpu_control.h>
static __always_inline void
libc_feholdexcept_setround_ppc (fenv_t *envp, int r)
{
fenv_union_t old, new;
old.fenv = *envp = fegetenv_register ();
__TEST_AND_ENTER_NON_STOP (old.l, 0ULL);
/* Clear everything and set the rounding mode. */
new.l = r;
fesetenv_register (new.fenv);
}
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);
__TEST_AND_EXIT_NON_STOP (old.l, new.l);
__TEST_AND_ENTER_NON_STOP (old.l, new.l);
/* 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;
}
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)
{
fenv_union_t new = { .fenv = *envp };
fegetenv_and_set_rn (new.l & FPSCR_RN_MASK);
}
static __always_inline int
libc_feupdateenv_test_ppc (fenv_t *envp, int ex)
{
return __libc_femergeenv_ppc (envp, ~FPSCR_CONTROL_MASK,
~FPSCR_STATUS_MASK) & 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;
ctx->env = old.fenv = fegetenv_and_set_rn (r);
ctx->updated_status = (r != (old.l & FPSCR_RN_MASK));
}
static __always_inline void
libc_feholdsetround_noex_ppc_ctx (struct rm_ctx *ctx, int r)
{
fenv_union_t old, new;
old.fenv = fegetenv_register ();
new.l = (old.l & ~(FPSCR_ENABLES_MASK|FPSCR_RN_MASK)) | r;
ctx->env = old.fenv;
if (__glibc_unlikely (new.l != old.l))
{
__TEST_AND_ENTER_NON_STOP (old.l, 0ULL);
fesetenv_mode (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_feholdsetround_noex_ctx libc_feholdsetround_noex_ppc_ctx
#define libc_feholdsetround_noexf_ctx libc_feholdsetround_noex_ppc_ctx
#define libc_feholdsetround_noexl_ctx libc_feholdsetround_noex_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
#include_next <fenv_private.h>
#endif