/* SPDX-License-Identifier: GPL-2.0 */
/* memmove.S: Simple memmove implementation.
 *
 * Copyright (C) 1997, 2004 David S. Miller (davem@redhat.com)
 * Copyright (C) 1996, 1997, 1998, 1999 Jakub Jelinek (jj@ultra.linux.cz)
 */

#include <linux/export.h>
#include <linux/linkage.h>

        .text
ENTRY(memmove) /* o0=dst o1=src o2=len */
        brz,pn          %o2, 99f
         mov            %o0, %g1

        cmp             %o0, %o1
        bleu,pt         %xcc, 2f
         add            %o1, %o2, %g7
        cmp             %g7, %o0
        bleu,pt         %xcc, memcpy
         add            %o0, %o2, %o5
        sub             %g7, 1, %o1

        sub             %o5, 1, %o0
1:      ldub            [%o1], %g7
        subcc           %o2, 1, %o2
        sub             %o1, 1, %o1
        stb             %g7, [%o0]
        bne,pt          %icc, 1b
         sub            %o0, 1, %o0
99:
        retl
         mov            %g1, %o0

        /* We can't just call memcpy for these memmove cases.  On some
         * chips the memcpy uses cache initializing stores and when dst
         * and src are close enough, those can clobber the source data
         * before we've loaded it in.
         */
2:      or              %o0, %o1, %g7
        or              %o2, %g7, %g7
        andcc           %g7, 0x7, %g0
        bne,pn          %xcc, 4f
         nop

3:      ldx             [%o1], %g7
        add             %o1, 8, %o1
        subcc           %o2, 8, %o2
        add             %o0, 8, %o0
        bne,pt          %icc, 3b
         stx            %g7, [%o0 - 0x8]
        ba,a,pt         %xcc, 99b

4:      ldub            [%o1], %g7
        add             %o1, 1, %o1
        subcc           %o2, 1, %o2
        add             %o0, 1, %o0
        bne,pt          %icc, 4b
         stb            %g7, [%o0 - 0x1]
        ba,a,pt         %xcc, 99b
ENDPROC(memmove)
EXPORT_SYMBOL(memmove)