path: root/sysdeps/powerpc/powerpc32/power6/memset.S

/* Optimized 32-bit memset implementation for POWER6.
   Copyright (C) 1997-2025 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/>.  */

#include <sysdep.h>

/* void * [r3] memset (void *s [r3], int c [r4], size_t n [r5]));
   Returns 's'.

   The memset is done in three sizes: byte (8 bits), word (32 bits),
   cache line (1024 bits). There is a special case for setting cache lines
   to 0, to take advantage of the dcbz instruction.  */

	.machine power6
EALIGN (memset, 7, 0)
	CALL_MCOUNT

#define rTMP	r0
#define rRTN	r3	/* Initial value of 1st argument.  */
#define rMEMP0	r3	/* Original value of 1st arg.  */
#define rCHR	r4	/* Char to set in each byte.  */
#define rLEN	r5	/* Length of region to set.  */
#define rMEMP	r6	/* Address at which we are storing.  */
#define rALIGN	r7	/* Number of bytes we are setting now (when aligning). */
#define rMEMP2	r8

#define rNEG64	r8	/* Constant -64 for clearing with dcbz.  */
#define rMEMP3	r9	/* Alt mem pointer.  */
L(_memset):
/* Take care of case for size <= 4.  */
	cmplwi	cr1, rLEN, 4
	andi.	rALIGN, rMEMP0, 3
	mr	rMEMP, rMEMP0
	ble-	cr1, L(small)
/* Align to word boundary.  */
	cmplwi	cr5, rLEN, 31
	insrwi	rCHR, rCHR, 8, 16	/* Replicate byte to halfword.  */
	beq+	L(aligned)
	mtcrf	0x01, rMEMP0
	subfic	rALIGN, rALIGN, 4
	add	rMEMP, rMEMP, rALIGN
	sub	rLEN, rLEN, rALIGN
	bf+	31, L(g0)
	stb	rCHR, 0(rMEMP0)
	bt	30, L(aligned)
L(g0):
	sth	rCHR, -2(rMEMP)

        .align 4
/* Handle the case of size < 31.  */
L(aligned):
	mtcrf	0x01, rLEN
	insrwi	rCHR, rCHR, 16, 0	/* Replicate halfword to word.  */
	ble	cr5, L(medium)
/* Align to 32-byte boundary.  */
	andi.	rALIGN, rMEMP, 0x1C
	subfic	rALIGN, rALIGN