1*19ef5b5bSuebayasi/* $NetBSD: memset.S,v 1.5 2014/05/23 03:17:31 uebayasi Exp $ */ 237c9f0a6Schristos 337c9f0a6Schristos/*- 437c9f0a6Schristos * Copyright (c) 2003 The NetBSD Foundation, Inc. 537c9f0a6Schristos * All rights reserved. 637c9f0a6Schristos * 737c9f0a6Schristos * This code is derived from software contributed to The NetBSD Foundation 837c9f0a6Schristos * by David Laight. 937c9f0a6Schristos * 1037c9f0a6Schristos * Redistribution and use in source and binary forms, with or without 1137c9f0a6Schristos * modification, are permitted provided that the following conditions 1237c9f0a6Schristos * are met: 1337c9f0a6Schristos * 1. Redistributions of source code must retain the above copyright 1437c9f0a6Schristos * notice, this list of conditions and the following disclaimer. 1537c9f0a6Schristos * 2. Redistributions in binary form must reproduce the above copyright 1637c9f0a6Schristos * notice, this list of conditions and the following disclaimer in the 1737c9f0a6Schristos * documentation and/or other materials provided with the distribution. 1837c9f0a6Schristos * 1937c9f0a6Schristos * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 2037c9f0a6Schristos * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 2137c9f0a6Schristos * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 2237c9f0a6Schristos * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 2337c9f0a6Schristos * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 2437c9f0a6Schristos * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 2537c9f0a6Schristos * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 2637c9f0a6Schristos * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 2737c9f0a6Schristos * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 2837c9f0a6Schristos * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 2937c9f0a6Schristos * POSSIBILITY OF SUCH DAMAGE. 3037c9f0a6Schristos */ 3137c9f0a6Schristos 3237c9f0a6Schristos#include <machine/asm.h> 3337c9f0a6Schristos 3437c9f0a6Schristos#if defined(LIBC_SCCS) 35*19ef5b5bSuebayasi RCSID("$NetBSD: memset.S,v 1.5 2014/05/23 03:17:31 uebayasi Exp $") 3637c9f0a6Schristos#endif 3737c9f0a6Schristos 3837c9f0a6Schristos#ifdef BZERO 3937c9f0a6SchristosENTRY(bzero) 4037c9f0a6Schristos#else 4137c9f0a6SchristosENTRY(memset) 4237c9f0a6Schristos#endif 4337c9f0a6Schristos#ifdef BZERO 4437c9f0a6Schristos movl 8(%esp),%ecx 4537c9f0a6Schristos xor %eax,%eax 4637c9f0a6Schristos#else 4737c9f0a6Schristos movl 12(%esp),%ecx 4837c9f0a6Schristos movzbl 8(%esp),%eax /* unsigned char, zero extend */ 4937c9f0a6Schristos#endif 5037c9f0a6Schristos cmpl $0x0f,%ecx /* avoid mispredicted branch... */ 5137c9f0a6Schristos 5237c9f0a6Schristos pushl %edi 5337c9f0a6Schristos movl 8(%esp),%edi 5437c9f0a6Schristos 5537c9f0a6Schristos /* 5637c9f0a6Schristos * if the string is too short, it's really not worth the overhead 5737c9f0a6Schristos * of aligning to word boundries, etc. So we jump to a plain 5837c9f0a6Schristos * unaligned set. 5937c9f0a6Schristos * 6037c9f0a6Schristos * NB aligning the transfer is actually pointless on my athlon 700, 6137c9f0a6Schristos * It does make a difference to a PII though. 6237c9f0a6Schristos * 6337c9f0a6Schristos * The PII, PIII and PIV all seem to have a massive performance 6437c9f0a6Schristos * drop when the initial target address is an odd multiple of 4. 6537c9f0a6Schristos */ 6688cde7b8Syamt jbe .Lby_bytes 6737c9f0a6Schristos 6837c9f0a6Schristos#ifndef BZERO 6937c9f0a6Schristos movb %al,%ah /* copy char to all bytes in word */ 7037c9f0a6Schristos movl %eax,%edx 7137c9f0a6Schristos sall $16,%eax 7237c9f0a6Schristos orl %edx,%eax 7337c9f0a6Schristos#endif 7437c9f0a6Schristos 7537c9f0a6Schristos movl %edi,%edx /* detect misalignment */ 7637c9f0a6Schristos neg %edx 7737c9f0a6Schristos andl $7,%edx 7888cde7b8Syamt jnz .Lalign 7988cde7b8Syamt.Laligned: 8037c9f0a6Schristos movl %eax,-4(%edi,%ecx) /* zap last 4 bytes */ 8137c9f0a6Schristos shrl $2,%ecx /* zero by words */ 8237c9f0a6Schristos rep 8337c9f0a6Schristos stosl 8488cde7b8Syamt.Ldone: 8537c9f0a6Schristos#ifndef BZERO 8637c9f0a6Schristos movl 8(%esp),%eax /* return address of buffer */ 8737c9f0a6Schristos#endif 8837c9f0a6Schristos pop %edi 8937c9f0a6Schristos ret 9037c9f0a6Schristos 9188cde7b8Syamt.Lalign: 9237c9f0a6Schristos movl %eax,(%edi) /* zap first 8 bytes */ 9337c9f0a6Schristos movl %eax,4(%edi) 9437c9f0a6Schristos subl %edx,%ecx /* remove from main count */ 9537c9f0a6Schristos add %edx,%edi 9688cde7b8Syamt jmp .Laligned 9737c9f0a6Schristos 9888cde7b8Syamt.Lby_bytes: 9937c9f0a6Schristos rep 10037c9f0a6Schristos stosb 10137c9f0a6Schristos 10237c9f0a6Schristos#ifndef BZERO 10337c9f0a6Schristos movl 8(%esp),%eax /* return address of buffer */ 10437c9f0a6Schristos#endif 10537c9f0a6Schristos popl %edi 10637c9f0a6Schristos ret 107*19ef5b5bSuebayasi#ifdef BZERO 108*19ef5b5bSuebayasiEND(bzero) 109*19ef5b5bSuebayasi#else 110*19ef5b5bSuebayasiEND(memset) 111*19ef5b5bSuebayasi#endif 112