memset.S revision 1.6.64.1
1 /* $NetBSD: memset.S,v 1.6.64.1 2011/03/05 20:55:28 rmind Exp $ */ 2 3 /*- 4 * Copyright (C) 2003 Matt Thomas <matt (at) 3am-software.com> 5 * Copyright (C) 2001 Martin J. Laubach <mjl (at) 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 #include <machine/asm.h> 33 34 /*----------------------------------------------------------------------*/ 35 /* 36 void bzero(void *b r3, size_t len r4); 37 void *memset(void *b r3, int c r4, size_t len r5); 38 */ 39 /*----------------------------------------------------------------------*/ 40 41 #define r_dst %r4 42 #define r_len %r5 43 #define r_tmp %r6 44 #define r_val %r0 45 46 ENTRY(bzero) 47 li r_val, 0 /* Value to fill with */ 48 mr r_len, %r4 49 b cb_memset 50 51 ENTRY(memset) 52 mr r_val, %r4 /* Value to fill with */ 53 54 cb_memset: 55 cmplwi r_len, 0 /* is the length 0? */ 56 beqlr- /* nothing to do */ 57 mr r_dst, %r3 58 /* 59 * r3=start, r4=dstptr, r5=length, r0=fill-val 60 */ 61 cmplwi r_len, 6 /* more than 6 bytes? */ 62 bgt complex_fill /* do it the complex way */ 63 subi r_dst, r_dst, 1 /* presubtract for stbu */ 64 simple_fill: mtctr r_len /* set CTR */ 65 1: stbu r_val, 1(r_dst) /* update memory */ 66 bdnz+ 1b /* until CTR is 0 */ 67 blr /* return */ 68 69 complex_fill: 70 rlwimi r_val, r_val, 8, 16, 23 /* word extend fill value */ 71 rlwimi r_val, r_val, 16, 0, 15 72 andi. r_tmp, r_dst, 0x03 73 beq+ word_fill /* already aligned to word? */ 74 andi. r_tmp, r_dst, 0x01 75 beq half_fill /* aligned to halfword? */ 76 stb r_val, 0(r_dst) 77 addi r_dst, r_dst, 1 78 subi r_len, r_len, 1 /* subtract byte */ 79 andi. r_tmp, r_dst, 0x02 80 beq word_fill /* aligned to word? */ 81 half_fill: 82 sth r_val, 0(r_dst) 83 addi r_dst, r_dst, 2 84 subi r_len, r_len, 2 /* subtract halfword */ 85 86 word_fill: 87 cmplwi r_len, 4 /* we have more than 4 bytes? */ 88 blt- trailing_bytes /* no? finish writing */ 89 srwi r_tmp, r_len, 2 /* get word count */ 90 mtctr r_tmp 91 subi r_dst, r_dst, 4 92 1: stwu r_val, 4(r_dst) 93 bdnz+ 1b 94 95 trailing_bytes: 96 andi. r_len, r_len, 0x03 /* how much left? */ 97 beqlr+ /* nothing? return */ 98 addi r_dst, r_dst, 3 99 b simple_fill 100
Indexes created Sun Sep 21 20:09:37 GMT 2025