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/* $NetBSD: memset.S,v 1.1 2014/09/03 19:34:25 matt Exp $ */
/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <machine/asm.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: memset.S,v 1.1 2014/09/03 19:34:25 matt Exp $")
#endif /* LIBC_SCCS && !lint */
/*----------------------------------------------------------------------*/
/*
void bzero(void *b r3, size_t len r4);
void * memset(void *b r3, int c r4, size_t len r5);
*/
/*----------------------------------------------------------------------*/
#ifdef _BZERO
#define r_fill r0
ENTRY(bzero)
#else
#define r_fill r4
ENTRY(memset)
#endif
#ifdef _BZERO
l.ori r5, r4, 0
l.or r4, r0, r0
#else
l.or r11, r3, r0 /* move start to return value */
#endif
l.sfeqi r5, 0 /* anything to do? */
l.bf .Lret /* no, just return */
l.nop
l.sfgeui r5, 7 /* small buffer? */
l.add r5, r5, r3 /* r5 is end pointer */
l.bnf .Lbyte_fill /* yes. just byte fill */
l.nop
#ifndef _BZERO
// Let's see the fill type
l.sfeqi r4, 0 /* filling with 0? */
l.bf .Lalignment_check /* don't to replicate */
l.nop
l.extbz r4, r4 /* truncate to 8 bits */
l.slli r13, r4, 8 /* shift left 8 bits */
l.or r4, r4, r13 /* merge the two bytes */
l.slli r13, r4, 16 /* shift left 16 bits */
l.or r4, r4, r13 /* merge the two halves */
.Lalignment_check:
#endif
l.andi r13, r3, 3 /* get low bits of start */
l.sfeqi r13, 0 /* word aligned? */
l.bf .Lword_fill /* yes, start setting */
l.nop
l.add r5, r5, r13 /* increase length */
l.sub r3, r3, r13 /* mask word aligned */
l.slli r13, r13, 3 /* bytes to bits */
l.addi r15, r13, -8 /* minus one byte */
l.lwz r6, 0(r3) /* get first word */
l.movhi r7, 0xff00 /* 0xff000000 */
l.sra r7, r7, r13 /* shift right align bytes */
l.and r6, r6, r7 /* clear bytes to be filled */
#ifndef _BZERO
l.srl r7, r_fill, r13 /* clear bytes to preserve */
l.or r6, r6, r7 /* merge existing with new */
#endif
l.sw 0(r3), r6 /* store first word */
l.addi r3, r3, 4 /* advance to next word */
l.addi r5, r5, -4 /* one less word to do */
.Lword_aligned:
l.srli r6, r5, 2 /* clear low two bits of len */
l.srli r6, r6, 2 /* ... */
l.sfgeu r3, r6 /* any more full words? */
l.bf .Lend_fill /* no, handle the last bytes */
l.nop
.Lword_fill:
l.sw 0(r3), r_fill /* store a word */
l.addi r3, r3, 4 /* advance */
l.sfgeu r3, r6 /* any more full words? */
l.bnf .Lword_fill /* yes, fill next word */
l.nop
l.j .Lend_fill /* fill any leftover bytes */
l.nop
.Lbyte_fill:
l.sb 0(r3), r_fill /* store a byte */
l.addi r3, r3, 1 /* advance */
.Lend_fill:
l.sfeq r3, r5 /* at the end? */
l.bnf .Lbyte_fill /* no, fill next byte */
l.nop
.Lret:
l.jr lr /* return */
l.nop
#ifdef _BZERO
END(bzero)
#else
END(memset)
#endif
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