/* $NetBSD: memset.S,v 1.7 2011/01/17 07:07:36 matt Exp $ */
/*-
* Copyright (C) 2003 Matt Thomas <
[email protected]>
* Copyright (C) 2001 Martin J. Laubach <
[email protected]>
* All rights reserved.
*
* 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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>
/*----------------------------------------------------------------------*/
/*
void bzero(void *b r3, size_t len r4);
void *memset(void *b r3, int c r4, size_t len r5);
*/
/*----------------------------------------------------------------------*/
#define r_dst %r4
#define r_len %r5
#define r_tmp %r6
#define r_val %r0
ENTRY(bzero)
li r_val, 0 /* Value to fill with */
mr r_len, %r4
b cb_memset
ENTRY(memset)
mr r_val, %r4 /* Value to fill with */
cb_memset:
cmplwi r_len, 0 /* is the length 0? */
beqlr- /* nothing to do */
mr r_dst, %r3
/*
* r3=start, r4=dstptr, r5=length, r0=fill-val
*/
cmplwi r_len, 6 /* more than 6 bytes? */
bgt complex_fill /* do it the complex way */
subi r_dst, r_dst, 1 /* presubtract for stbu */
simple_fill: mtctr r_len /* set CTR */
1: stbu r_val, 1(r_dst) /* update memory */
bdnz+ 1b /* until CTR is 0 */
blr /* return */
complex_fill:
rlwimi r_val, r_val, 8, 16, 23 /* word extend fill value */
rlwimi r_val, r_val, 16, 0, 15
andi. r_tmp, r_dst, 0x03
beq+ word_fill /* already aligned to word? */
andi. r_tmp, r_dst, 0x01
beq half_fill /* aligned to halfword? */
stb r_val, 0(r_dst)
addi r_dst, r_dst, 1
subi r_len, r_len, 1 /* subtract byte */
andi. r_tmp, r_dst, 0x02
beq word_fill /* aligned to word? */
half_fill:
sth r_val, 0(r_dst)
addi r_dst, r_dst, 2
subi r_len, r_len, 2 /* subtract halfword */
word_fill:
cmplwi r_len, 4 /* we have more than 4 bytes? */
blt- trailing_bytes /* no? finish writing */
srwi r_tmp, r_len, 2 /* get word count */
mtctr r_tmp
subi r_dst, r_dst, 4
1: stwu r_val, 4(r_dst)
bdnz+ 1b
trailing_bytes:
andi. r_len, r_len, 0x03 /* how much left? */
beqlr+ /* nothing? return */
addi r_dst, r_dst, 3
b simple_fill
