bzero.S revision 67208
167117Sdfr/*- 267117Sdfr * Copyright (c) 2000 Doug Rabson 367117Sdfr * All rights reserved. 467117Sdfr * 567117Sdfr * Redistribution and use in source and binary forms, with or without 667117Sdfr * modification, are permitted provided that the following conditions 767117Sdfr * are met: 867117Sdfr * 1. Redistributions of source code must retain the above copyright 967117Sdfr * notice, this list of conditions and the following disclaimer. 1067117Sdfr * 2. Redistributions in binary form must reproduce the above copyright 1167117Sdfr * notice, this list of conditions and the following disclaimer in the 1267117Sdfr * documentation and/or other materials provided with the distribution. 1367117Sdfr * 1467117Sdfr * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1567117Sdfr * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1667117Sdfr * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1767117Sdfr * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1867117Sdfr * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 1967117Sdfr * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2067117Sdfr * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2167117Sdfr * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2267117Sdfr * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2367117Sdfr * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2467117Sdfr * SUCH DAMAGE. 2567117Sdfr * 2667117Sdfr * $FreeBSD: head/lib/libc/ia64/string/bzero.S 67208 2000-10-16 16:48:48Z dfr $ 2767117Sdfr */ 2867117Sdfr 2967117Sdfr#include <machine/asm.h> 3067117Sdfr 3167117SdfrENTRY(bzero, 2) 3267117Sdfr 3367117Sdfr cmp.le p6,p0=in1,r0 // bail if len <= 0 3467117Sdfr(p6) br.ret.spnt.few rp 3567117Sdfr 3667117Sdfr mov r14=ar.lc // save ar.lc 3767117Sdfr 3867208Sdfr cmp.ltu p6,p0=17,in1 // check for small 3967208Sdfr(p6) br.dptk.few 3f 4067117Sdfr 4167208Sdfr add r15=-1,in1 ;; 4267208Sdfr1: mov ar.lc=r15 4367117Sdfr2: st1 [in0]=r0,1 // zero one byte 4467117Sdfr br.cloop.sptk.few 2b // loop 4567117Sdfr 4667117Sdfr mov ar.lc=r14 // done 4767117Sdfr br.ret.sptk.few rp 4867117Sdfr 4967117Sdfr // Zero up to 8byte alignment 5067208Sdfr 5167208Sdfr3: tbit.nz p6,p0=in1,0 ;; 5267117Sdfr(p6) st1 [in0]=r0,1 5367117Sdfr(p6) add in1=-1,in1 5467117Sdfr 5567117Sdfr tbit.nz p6,p0=in1,1 ;; 5667117Sdfr(p6) st2 [in0]=r0,2 5767117Sdfr(p6) add in1=-2,in1 5867117Sdfr 5967117Sdfr tbit.nz p6,p0=in1,2 ;; 6067117Sdfr(p6) st4 [in0]=r0,4 6167117Sdfr(p6) add in1=-4,in1 6267117Sdfr 6367117Sdfr shr.u r15=in1,3 // word count 6467117Sdfr extr.u in1=in1,0,3 ;; // trailing bytes 6567117Sdfr cmp.eq p6,p0=r15,r0 // check for zero 6667117Sdfr cmp.ne p7,p0=in1,r0 6767117Sdfr(p6) br.dpnt.few 1b // zero last bytes 6867117Sdfr 6967208Sdfr add r15=-1,r15 ;; 7067117Sdfr mov ar.lc=r15 7167208Sdfr4: st8 [in0]=r0,8 7267208Sdfr br.cloop.sptk.few 4b 7367117Sdfr 7467117Sdfr(p7) br.dpnt.few 1b // zero last bytes 7567117Sdfr 7667117Sdfr mov ar.lc=r14 // done 7767117Sdfr br.ret.sptk.few rp 7867117Sdfr 7967117SdfrEND(bzero)