/* $NetBSD: bzero.S,v 1.10 2009/12/14 02:53:52 matt Exp $ */ /*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Ralph Campbell. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <machine/asm.h> __FBSDID("$FreeBSD$"); #if defined(LIBC_SCCS) && !defined(lint) #if 0 ASMSTR("from: @(#)bzero.s 8.1 (Berkeley) 6/4/93") #else ASMSTR("$NetBSD: bzero.S,v 1.10 2009/12/14 02:53:52 matt Exp $") #endif #endif /* LIBC_SCCS and not lint */ #define _LOCORE /* XXX not really, just assembly-code source */ #include <machine/endian.h> #ifdef __ABICALLS__ .abicalls #endif /* bzero(s1, n) */ LEAF(bzero) .set noreorder blt a1, 3*SZREG, smallclr # small amount to clear? PTR_SUBU a3, zero, a0 # compute # bytes to word align address and a3, a3, SZREG-1 beq a3, zero, 1f # skip if word aligned PTR_SUBU a1, a1, a3 # subtract from remaining count REG_SHI zero, 0(a0) # clear 1, 2, or 3 bytes to align PTR_ADDU a0, a0, a3 1: and v0, a1, SZREG-1 # compute number of words left PTR_SUBU a3, a1, v0 move a1, v0 PTR_ADDU a3, a3, a0 # compute ending address 2: PTR_ADDU a0, a0, SZREG # clear words bne a0, a3, 2b # unrolling loop doesnt help REG_S zero, -SZREG(a0) # since we are limited by memory speed smallclr: ble a1, zero, 2f PTR_ADDU a3, a1, a0 # compute ending address 1: PTR_ADDU a0, a0, 1 # clear bytes bne a0, a3, 1b sb zero, -1(a0) 2: j ra nop END(bzero) |