1/* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22/* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 .file "memset.s" 28 29/* 30 * char *memset(sp, c, n) 31 * 32 * Set an array of n chars starting at sp to the character c. 33 * Return sp. 34 * 35 * Fast assembler language version of the following C-program for memset 36 * which represents the `standard' for the C-library. 37 * 38 * void * 39 * memset(void *sp1, int c, size_t n) 40 * { 41 * if (n != 0) { 42 * char *sp = sp1; 43 * do { 44 * *sp++ = (char)c; 45 * } while (--n != 0); 46 * } 47 * return (sp1); 48 * } 49 */ 50 51#include <sys/asm_linkage.h> 52 53 ANSI_PRAGMA_WEAK(memset,function) 54 55 ENTRY(memset) 56 mov %o0, %o5 ! copy sp before using it 57 cmp %o2, 7 ! if small counts, just write bytes 58 blu .wrchar 59 .empty ! following lable is ok in delay slot 60 61.walign:btst 3, %o5 ! if bigger, align to 4 bytes 62 bz .wrword 63 andn %o2, 3, %o3 ! create word sized count in %o3 64 dec %o2 ! decrement count 65 stb %o1, [%o5] ! clear a byte 66 b .walign 67 inc %o5 ! next byte 68 69.wrword:and %o1, 0xff, %o1 ! generate a word filled with c 70 sll %o1, 8, %o4 71 or %o1, %o4, %o1 72 sll %o1, 16, %o4 73 or %o1, %o4, %o1 741: st %o1, [%o5] ! word writing loop 75 subcc %o3, 4, %o3 76 bnz 1b 77 inc 4, %o5 78 79 and %o2, 3, %o2 ! leftover count, if any 80.wrchar:deccc %o2 ! byte clearing loop 81 inc %o5 82 bgeu,a .wrchar 83 stb %o1, [%o5 + -1] ! we've already incremented the address 84 85 retl 86 nop 87 88 SET_SIZE(memset) 89