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powerpc: Add string-fza.h

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While ppc has the more important string functions in assembly,
there are still a few generic routines used.

Use the Power 6 CMPB insn for testing of zeros.

Checked on powerpc64le-linux-gnu.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Richard Henderson 2023-01-10 18:01:05 -03:00 committed by Adhemerval Zanella
parent 885306b2f6
commit 080685c90f
1 changed files with 71 additions and 0 deletions
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sysdeps/powerpc/string-fza.h Normal file
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/* Zero byte detection; basics. PowerPC version.
Copyright (C) 2023 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 _POWERPC_STRING_FZA_H
#define _POWERPC_STRING_FZA_H 1
/* PowerISA 2.05 (POWER6) provides cmpb instruction. */
#ifdef _ARCH_PWR6
# include <string-misc.h>
# include <string-optype.h>
/* The functions return a byte mask. */
typedef op_t find_t;
/* This function returns 0xff for each byte that is
equal between X1 and X2. */
static __always_inline find_t
find_eq_all (op_t x1, op_t x2)
{
return __builtin_cmpb (x1, x2);
}
/* This function returns 0xff for each byte that is zero in X. */
static __always_inline find_t
find_zero_all (op_t x)
{
return find_eq_all (x, 0);
}
/* Identify zero bytes in X1 or equality between X1 and X2. */
static __always_inline find_t
find_zero_eq_all (op_t x1, op_t x2)
{
return find_zero_all (x1) | find_eq_all (x1, x2);
}
/* Identify zero bytes in X1 or inequality between X1 and X2. */
static __always_inline find_t
find_zero_ne_all (op_t x1, op_t x2)
{
return find_zero_all (x1) | ~find_eq_all (x1, x2);
}
/* Define the "inexact" versions in terms of the exact versions. */
# define find_zero_low find_zero_all
# define find_eq_low find_eq_all
# define find_zero_eq_low find_zero_eq_all
#else
# include <sysdeps/generic/string-fza.h>
#endif /* _ARCH_PWR6 */
#endif /* _POWERPC_STRING_FZA_H */