/*      $NetBSD: bzero.S,v 1.1 2016/08/05 15:06:02 scole Exp $  */

/*-
* Copyright (c) 2000 Doug Rabson
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* __FBSDID("$FreeBSD: releng/10.1/lib/libc/ia64/string/bzero.S 125669 2004-02-10 20:45:28Z cperciva $");
*/

#include <machine/asm.h>

/*
* void
* bzero(void *b, size_t len);
*/
ENTRY(bzero, 2)

       cmp.le  p6,p0=in1,r0                    // bail if len <= 0
(p6)    br.ret.spnt.few rp
       ;;
       mov     r14=ar.lc                       // save ar.lc

       cmp.ltu p6,p0=17,in1                    // check for small
(p6)    br.dptk.few 3f

1:      add     r15=-1,in1 ;;
       mov     ar.lc=r15 ;;
2:      st1     [in0]=r0,1                      // zero one byte
       br.cloop.sptk.few 2b                    // loop

       ;;
       mov     ar.lc=r14                       // done
       br.ret.sptk.few rp

       // Zero up to 8byte alignment

3:      tbit.nz p6,p0=in0,0 ;;
(p6)    st1     [in0]=r0,1
(p6)    add     in1=-1,in1 ;;

       tbit.nz p6,p0=in0,1 ;;
(p6)    st2     [in0]=r0,2
(p6)    add     in1=-2,in1 ;;

       tbit.nz p6,p0=in0,2 ;;
(p6)    st4     [in0]=r0,4
(p6)    add     in1=-4,in1

       ;;
       shr.u   r15=in1,3                       // word count
       extr.u  in1=in1,0,3 ;;                  // trailing bytes
       cmp.eq  p6,p0=r15,r0                    // check for zero
       cmp.ne  p7,p0=in1,r0
(p6)    br.dpnt.few 1b                          // zero last bytes

       add     r15=-1,r15 ;;
       mov     ar.lc=r15 ;;
4:      st8     [in0]=r0,8
       br.cloop.sptk.few 4b

(p7)    br.dpnt.few 1b                          // zero last bytes

       ;;
       mov     ar.lc=r14                       // done
       br.ret.sptk.few rp

END(bzero)