/*      $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)