1/* $NetBSD: memset.S,v 1.6 2007/03/04 06:03:12 christos Exp $ */ 2 3/*- 4 * Copyright (C) 2003 Matt Thomas <matt@3am-software.com> 5 * Copyright (C) 2001 Martin J. Laubach <mjl@NetBSD.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30/*----------------------------------------------------------------------*/ 31 32#define _NOREGNAMES 33#include <machine/asm.h> 34 35/*----------------------------------------------------------------------*/ 36/* 37 void bzero(void *b r3, size_t len r4); 38 void *memset(void *b r3, int c r4, size_t len r5); 39*/ 40/*----------------------------------------------------------------------*/ 41 42#define r_dst %r4 43#define r_len %r5 44#define r_tmp %r6 45#define r_val %r0 46 47ENTRY(bzero) 48 li r_val, 0 /* Value to fill with */ 49 mr r_len, %r4 50 b cb_memset 51 52ENTRY(memset) 53 mr r_val, %r4 /* Value to fill with */ 54 55cb_memset: 56 cmplwi r_len, 0 /* is the length 0? */ 57 beqlr- /* nothing to do */ 58 mr r_dst, %r3 59 /* 60 * r3=start, r4=dstptr, r5=length, r0=fill-val 61 */ 62 cmplwi r_len, 6 /* more than 6 bytes? */ 63 bgt complex_fill /* do it the complex way */ 64 subi r_dst, r_dst, 1 /* presubtract for stbu */ 65simple_fill: mtctr r_len /* set CTR */ 661: stbu r_val, 1(r_dst) /* update memory */ 67 bdnz+ 1b /* until CTR is 0 */ 68 blr /* return */ 69 70complex_fill: 71 rlwimi r_val, r_val, 8, 16, 23 /* word extend fill value */ 72 rlwimi r_val, r_val, 16, 0, 15 73 andi. r_tmp, r_dst, 0x03 74 beq+ word_fill /* already aligned to word? */ 75 andi. r_tmp, r_dst, 0x01 76 beq half_fill /* aligned to halfword? */ 77 stb r_val, 0(r_dst) 78 addi r_dst, r_dst, 1 79 subi r_len, r_len, 1 /* subtract byte */ 80 andi. r_tmp, r_dst, 0x02 81 beq word_fill /* aligned to word? */ 82half_fill: 83 sth r_val, 0(r_dst) 84 addi r_dst, r_dst, 2 85 subi r_len, r_len, 2 /* subtract halfword */ 86 87word_fill: 88 cmplwi r_len, 4 /* we have more than 4 bytes? */ 89 blt- trailing_bytes /* no? finish writing */ 90 srwi r_tmp, r_len, 2 /* get word count */ 91 mtctr r_tmp 92 subi r_dst, r_dst, 4 931: stwu r_val, 4(r_dst) 94 bdnz+ 1b 95 96trailing_bytes: 97 andi. r_len, r_len, 0x03 /* how much left? */ 98 beqlr+ /* nothing? return */ 99 addi r_dst, r_dst, 3 100 b simple_fill 101