bzero.S revision 1.1.26.1
1 /* $NetBSD: bzero.S,v 1.1.26.1 2008/05/18 12:28:45 yamt Exp $ */ 2 3 /*- 4 * Copyright (c) 1997 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by J.T. Conklin. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /*- 33 * Copyright (c) 1990 The Regents of the University of California. 34 * All rights reserved. 35 * 36 * This code is derived from software contributed to Berkeley by 37 * the Systems Programming Group of the University of Utah Computer 38 * Science Department. 39 * 40 * Redistribution and use in source and binary forms, with or without 41 * modification, are permitted provided that the following conditions 42 * are met: 43 * 1. Redistributions of source code must retain the above copyright 44 * notice, this list of conditions and the following disclaimer. 45 * 2. Redistributions in binary form must reproduce the above copyright 46 * notice, this list of conditions and the following disclaimer in the 47 * documentation and/or other materials provided with the distribution. 48 * 3. Neither the name of the University nor the names of its contributors 49 * may be used to endorse or promote products derived from this software 50 * without specific prior written permission. 51 * 52 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 53 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 54 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 55 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 56 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 57 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 58 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 59 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 60 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 61 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 62 * SUCH DAMAGE. 63 */ 64 65 #include <machine/asm.h> 66 67 #if defined(LIBC_SCCS) && !defined(lint) 68 #if 0 69 RCSID("from: @(#)bzero.s 5.1 (Berkeley) 5/12/90") 70 #else 71 RCSID("$NetBSD: bzero.S,v 1.1.26.1 2008/05/18 12:28:45 yamt Exp $") 72 #endif 73 #endif /* LIBC_SCCS and not lint */ 74 75 ENTRY(bzero) 76 movl %d2,%sp@- 77 movl %sp@(8),%a0 | destination 78 movl %sp@(12),%d1 | count 79 80 movql #0,%d2 81 82 /* 83 * It isn't worth the overhead of aligning to {long}word boundries 84 * if the string is too short. 85 */ 86 cmpl #8,%d1 87 jlt Lbzbyte 88 89 /* word align */ 90 movl %a0,%d0 91 btst #0,%d0 | if (dst & 1) 92 jeq Lbzalgndw | 93 movb %d2,%a0@+ | *(char *)dst++ = 0 94 subql #1,%d1 | len-- 95 Lbzalgndw: 96 /* long word align */ 97 btst #1,%d0 | if (dst & 2) 98 jeq Lbzalgndl | 99 movw %d2,%a0@+ | *(short *)dst++ = 0 100 subql #2,%d1 | len -= 2 101 Lbzalgndl: 102 /* zero by 8 longwords */ 103 movel %d1,%d0 104 lsrl #5,%d0 | cnt = len / 32 105 jeq Lbzlong | if (cnt) 106 andl #31,%d1 | len %= 32 107 subql #1,%d0 | set up for dbf 108 Lbz32loop: 109 movl %d2,%a0@+ | zero 8 long words 110 movl %d2,%a0@+ 111 movl %d2,%a0@+ 112 movl %d2,%a0@+ 113 movl %d2,%a0@+ 114 movl %d2,%a0@+ 115 movl %d2,%a0@+ 116 movl %d2,%a0@+ 117 dbf %d0,Lbz32loop | till done 118 clrw %d0 119 subql #1,%d0 120 jcc Lbz32loop 121 122 Lbzlong: 123 /* copy by longwords */ 124 movel %d1,%d0 125 lsrl #2,%d0 | cnt = len / 4 126 jeq Lbzbyte | if (cnt) 127 subql #1,%d0 | set up for dbf 128 Lbzlloop: 129 movl %d2,%a0@+ | clear longwords 130 dbf %d0,Lbzlloop | till done 131 andl #3,%d1 | len %= 4 132 jeq Lbzdone 133 134 subql #1,%d1 | set up for dbf 135 Lbzbloop: 136 movb %d2,%a0@+ | zero bytes 137 Lbzbyte: 138 dbf %d1,Lbzbloop | till done 139 Lbzdone: 140 movl %sp@+,%d2 141 rts 142
Indexes created Thu Oct 23 22:10:10 GMT 2025