1*7c478bd9Sstevel@tonic-gate/* 2*7c478bd9Sstevel@tonic-gate * CDDL HEADER START 3*7c478bd9Sstevel@tonic-gate * 4*7c478bd9Sstevel@tonic-gate * The contents of this file are subject to the terms of the 5*7c478bd9Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only 6*7c478bd9Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance 7*7c478bd9Sstevel@tonic-gate * with the License. 8*7c478bd9Sstevel@tonic-gate * 9*7c478bd9Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10*7c478bd9Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing. 11*7c478bd9Sstevel@tonic-gate * See the License for the specific language governing permissions 12*7c478bd9Sstevel@tonic-gate * and limitations under the License. 13*7c478bd9Sstevel@tonic-gate * 14*7c478bd9Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each 15*7c478bd9Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16*7c478bd9Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the 17*7c478bd9Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying 18*7c478bd9Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner] 19*7c478bd9Sstevel@tonic-gate * 20*7c478bd9Sstevel@tonic-gate * CDDL HEADER END 21*7c478bd9Sstevel@tonic-gate */ 22*7c478bd9Sstevel@tonic-gate/* 23*7c478bd9Sstevel@tonic-gate * Copyright (c) 1990, 1991 Sun Microsystems, Inc. 24*7c478bd9Sstevel@tonic-gate */ 25*7c478bd9Sstevel@tonic-gate 26*7c478bd9Sstevel@tonic-gate#ident "%Z%%M% %I% %E% SMI" 27*7c478bd9Sstevel@tonic-gate 28*7c478bd9Sstevel@tonic-gate/* 29*7c478bd9Sstevel@tonic-gate * Routine to zero out a section of memory (the tail end of the data segment 30*7c478bd9Sstevel@tonic-gate * upto a page boundary). First nibble off any bytes up to the first double 31*7c478bd9Sstevel@tonic-gate * aligned word, and then clear doubles until the byte count is zero. Note, 32*7c478bd9Sstevel@tonic-gate * this assumes the count specified has been rounded to end on a double word 33*7c478bd9Sstevel@tonic-gate * boundary. 34*7c478bd9Sstevel@tonic-gate * 35*7c478bd9Sstevel@tonic-gate * %o0 = addr, %o1 = len 36*7c478bd9Sstevel@tonic-gate */ 37*7c478bd9Sstevel@tonic-gate 38*7c478bd9Sstevel@tonic-gate .seg "text" 39*7c478bd9Sstevel@tonic-gate .global __zero 40*7c478bd9Sstevel@tonic-gate__zero: 41*7c478bd9Sstevel@tonic-gate tst %o1 ! Have we any count at all? 42*7c478bd9Sstevel@tonic-gate ba 3f ! Go find out, 43*7c478bd9Sstevel@tonic-gate clr %g1 ! but prepare for long loop 44*7c478bd9Sstevel@tonic-gate 45*7c478bd9Sstevel@tonic-gate! Byte clearing loop 46*7c478bd9Sstevel@tonic-gate 47*7c478bd9Sstevel@tonic-gate0: 48*7c478bd9Sstevel@tonic-gate inc %o0 ! Bump address 49*7c478bd9Sstevel@tonic-gate deccc %o1 ! Decrement count 50*7c478bd9Sstevel@tonic-gate3: 51*7c478bd9Sstevel@tonic-gate bz 1f ! If no count left, exit 52*7c478bd9Sstevel@tonic-gate andcc %o0, 7, %g0 ! Is the address less than double-word aligned? 53*7c478bd9Sstevel@tonic-gate bnz,a 0b ! Branch if so 54*7c478bd9Sstevel@tonic-gate clrb [%o0] ! but clear the current byte anyway 55*7c478bd9Sstevel@tonic-gate 56*7c478bd9Sstevel@tonic-gate! Double clearing loop 57*7c478bd9Sstevel@tonic-gate 58*7c478bd9Sstevel@tonic-gate2: 59*7c478bd9Sstevel@tonic-gate std %g0, [%o0] ! Clear next 8 bytes 60*7c478bd9Sstevel@tonic-gate subcc %o1, 8, %o1 ! Decrement count 61*7c478bd9Sstevel@tonic-gate bnz 2b ! Branch if any left 62*7c478bd9Sstevel@tonic-gate inc 8, %o0 ! but always increment address by 8 63*7c478bd9Sstevel@tonic-gate1: 64*7c478bd9Sstevel@tonic-gate retl ! Go home 65*7c478bd9Sstevel@tonic-gate nop 66