Subversion Repositories HelenOS

#
# Copyright (c) 2007 Michal Kebrt
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - 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.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
#


.text

.global memcpy

memcpy:
    add     r3, r1, #3
    bic     r3, r3, #3
    cmp     r1, r3
    stmdb   sp!, {r4, lr}
    beq     case_4
case_1:
    cmp     r2, #0
    movne   ip, #0
    beq     case_3
case_2:
    ldrb    r3, [ip, r1]
    strb    r3, [ip, r0]
    add     ip, ip, #1
    cmp     ip, r2
    bne     case_2
case_3:
    mov     r0, r1
    ldmia   sp!, {r4, pc}
case_4:
    add     r3, r0, #3
    bic     r3, r3, #3
    cmp     r0, r3
    bne     case_1
    movs    r4, r2, lsr #2
    moveq   lr, r4
    beq     case_6
    mov     lr, #0
    mov     ip, lr
case_5:
    ldr     r3, [ip, r1]
    add     lr, lr, #1
    cmp     lr, r4
    str     r3, [ip, r0]
    add     ip, ip, #4
    bne     case_5
case_6:
    ands    r4, r2, #3
    beq     case_3
    mov     r3, lr, lsl #2
    add     r0, r3, r0
    add     ip, r3, r1
    mov     r2, #0
case_7:
    ldrb    r3, [r2, ip]
    strb    r3, [r2, r0]
    add     r2, r2, #1
    cmp     r2, r4
    bne     case_7
    b       case_3