11849Swollman/* 21849Swollman * Copyright (c) 1993 Winning Strategies, Inc. 31849Swollman * All rights reserved. 41849Swollman * 51849Swollman * Redistribution and use in source and binary forms, with or without 61849Swollman * modification, are permitted provided that the following conditions 71849Swollman * are met: 81849Swollman * 1. Redistributions of source code must retain the above copyright 91849Swollman * notice, this list of conditions and the following disclaimer. 101849Swollman * 2. Redistributions in binary form must reproduce the above copyright 111849Swollman * notice, this list of conditions and the following disclaimer in the 121849Swollman * documentation and/or other materials provided with the distribution. 131849Swollman * 3. All advertising materials mentioning features or use of this software 141849Swollman * must display the following acknowledgement: 151849Swollman * This product includes software developed by Winning Strategies, Inc. 161849Swollman * 4. The name of the author may not be used to endorse or promote products 1797748Sschweikh * derived from this software without specific prior written permission 181849Swollman * 191849Swollman * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 201849Swollman * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 211849Swollman * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 221849Swollman * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 231849Swollman * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 241849Swollman * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 251849Swollman * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 261849Swollman * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 271849Swollman * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 281849Swollman * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 291849Swollman */ 301849Swollman 3185437Speter#include <machine/asm.h> 3293000Sobrien__FBSDID("$FreeBSD$"); 331849Swollman 341849Swollman/* 351849Swollman * bzero (void *b, size_t len) 361849Swollman * write len zero bytes to the string b. 371849Swollman * 381849Swollman * Written by: 391849Swollman * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc. 401849Swollman */ 411849Swollman 421849SwollmanENTRY(bzero) 431849Swollman pushl %edi 441849Swollman pushl %ebx 451849Swollman movl 12(%esp),%edi 461849Swollman movl 16(%esp),%ecx 471849Swollman 481849Swollman cld /* set fill direction forward */ 491849Swollman xorl %eax,%eax /* set fill data to 0 */ 501849Swollman 511849Swollman /* 521849Swollman * if the string is too short, it's really not worth the overhead 531849Swollman * of aligning to word boundries, etc. So we jump to a plain 541849Swollman * unaligned set. 551849Swollman */ 561849Swollman cmpl $0x0f,%ecx 571849Swollman jle L1 581849Swollman 591849Swollman movl %edi,%edx /* compute misalignment */ 601849Swollman negl %edx 611849Swollman andl $3,%edx 621849Swollman movl %ecx,%ebx 631849Swollman subl %edx,%ebx 641849Swollman 651849Swollman movl %edx,%ecx /* zero until word aligned */ 661849Swollman rep 671849Swollman stosb 681849Swollman 691849Swollman movl %ebx,%ecx /* zero by words */ 701849Swollman shrl $2,%ecx 711849Swollman rep 721849Swollman stosl 731849Swollman 741849Swollman movl %ebx,%ecx 751849Swollman andl $3,%ecx /* zero remainder by bytes */ 761849SwollmanL1: rep 771849Swollman stosb 781849Swollman 791849Swollman popl %ebx 801849Swollman popl %edi 811849Swollman ret 82184548SpeterEND(bzero) 83217106Skib 84217106Skib .section .note.GNU-stack,"",%progbits 85