/*      $NetBSD: bcopy.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/bcopy.S 125669 2004-02-10 20:45:28Z cperciva $");
 */

#include <machine/asm.h>

/*
 * void
 * bcopy(const void *src, void *dst, size_t len);
 */

/*
 * Not the fastest bcopy in the world.
 */
ENTRY(bcopy, 3)

        cmp.le  p6,p0=in2,r0                    // bail if len <= 0
(p6)    br.ret.spnt.few rp

        sub     r14=in1,in0 ;;                  // check for overlap
        cmp.ltu p6,p0=r14,in2                   // dst-src < len
(p6)    br.cond.spnt.few 5f

        extr.u  r14=in0,0,3                     // src & 7
        extr.u  r15=in1,0,3 ;;                  // dst & 7
        cmp.eq  p6,p0=r14,r15                   // different alignment?
(p6)    br.cond.spnt.few 2f                     // branch if same alignment

1:      ld1     r14=[in0],1 ;;                  // copy bytewise
        st1     [in1]=r14,1
        add     in2=-1,in2 ;;                   // len--
        cmp.ne  p6,p0=r0,in2
(p6)    br.cond.dptk.few 1b                     // loop
        br.ret.sptk.few rp                      // done

2:      cmp.eq  p6,p0=r14,r0                    // aligned?
(p6)    br.cond.sptk.few 4f

3:      ld1     r14=[in0],1 ;;                  // copy bytewise
        st1     [in1]=r14,1
        extr.u  r15=in0,0,3                     // src & 7
        add     in2=-1,in2 ;;                   // len--
        cmp.eq  p6,p0=r0,in2                    // done?
        cmp.eq  p7,p0=r0,r15 ;;                 // aligned now?
(p6)    br.ret.spnt.few rp                      // return if done
(p7)    br.cond.spnt.few 4f                     // go to main copy
        br.cond.sptk.few 3b                     // more bytes to copy

        // At this point, in2 is non-zero

4:      mov     r14=8 ;;
        cmp.ltu p6,p0=in2,r14 ;;                // len < 8?
(p6)    br.cond.spnt.few 1b                     // byte copy the end
        ld8     r15=[in0],8 ;;                  // copy word
        st8     [in1]=r15,8
        add     in2=-8,in2 ;;                   // len -= 8
        cmp.ne  p6,p0=r0,in2                    // done?
(p6)    br.cond.spnt.few 4b                     // again

        br.ret.sptk.few rp                      // return

        // Don't bother optimising overlap case

5:      add     in0=in0,in2
        add     in1=in1,in2 ;;
        add     in0=-1,in0
        add     in1=-1,in1 ;;

6:      ld1     r14=[in0],-1 ;;
        st1     [in1]=r14,-1
        add     in2=-1,in2 ;;
        cmp.ne  p6,p0=r0,in2
(p6)    br.cond.spnt.few 6b

        br.ret.sptk.few rp
END(bcopy)