bzero.S revision 83822
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 83822 2001-09-22 18:27:01Z 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 4183822Sdfr1: add r15=-1,in1 ;; 4283822Sdfr mov ar.lc=r15 ;; 4367117Sdfr2: st1 [in0]=r0,1 // zero one byte 4467117Sdfr br.cloop.sptk.few 2b // loop 4567117Sdfr 4683822Sdfr ;; 4767117Sdfr mov ar.lc=r14 // done 4867117Sdfr br.ret.sptk.few rp 4967117Sdfr 5067117Sdfr // Zero up to 8byte alignment 5167208Sdfr 5283822Sdfr3: tbit.nz p6,p0=in0,0 ;; 5367117Sdfr(p6) st1 [in0]=r0,1 5467117Sdfr(p6) add in1=-1,in1 5567117Sdfr 5683822Sdfr tbit.nz p6,p0=in0,1 ;; 5767117Sdfr(p6) st2 [in0]=r0,2 5867117Sdfr(p6) add in1=-2,in1 5967117Sdfr 6083822Sdfr tbit.nz p6,p0=in0,2 ;; 6167117Sdfr(p6) st4 [in0]=r0,4 6267117Sdfr(p6) add in1=-4,in1 6367117Sdfr 6483822Sdfr ;; 6567117Sdfr shr.u r15=in1,3 // word count 6667117Sdfr extr.u in1=in1,0,3 ;; // trailing bytes 6767117Sdfr cmp.eq p6,p0=r15,r0 // check for zero 6867117Sdfr cmp.ne p7,p0=in1,r0 6967117Sdfr(p6) br.dpnt.few 1b // zero last bytes 7067117Sdfr 7167208Sdfr add r15=-1,r15 ;; 7283822Sdfr mov ar.lc=r15 ;; 7367208Sdfr4: st8 [in0]=r0,8 7467208Sdfr br.cloop.sptk.few 4b 7567117Sdfr 7667117Sdfr(p7) br.dpnt.few 1b // zero last bytes 7767117Sdfr 7883822Sdfr ;; 7967117Sdfr mov ar.lc=r14 // done 8067117Sdfr br.ret.sptk.few rp 8167117Sdfr 8283822SdfrEND(bzero) 83