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/* MN10300 Optimised simple memory to memory copy
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <asm/cache.h>
.section .text
.balign L1_CACHE_BYTES
###############################################################################
#
# void *memcpy(void *dst, const void *src, size_t n)
#
###############################################################################
.globl memcpy
.type memcpy,@function
memcpy:
movm [d2,d3],(sp)
mov d0,(12,sp)
mov d1,(16,sp)
mov (20,sp),d2 # count
mov d0,a0 # dst
mov d1,a1 # src
mov d0,e3 # the return value
cmp +0,d2
beq memcpy_done # return if zero-length copy
# see if the three parameters are all four-byte aligned
or d0,d1,d3
or d2,d3
and +3,d3
bne memcpy_1 # jump if not
# we want to transfer as much as we can in chunks of 32 bytes
cmp +31,d2
bls memcpy_4_remainder # 4-byte aligned remainder
movm [exreg1],(sp)
add -32,d2
mov +32,d3
memcpy_4_loop:
mov (a1+),d0
mov (a1+),d1
mov (a1+),e0
mov (a1+),e1
mov (a1+),e4
mov (a1+),e5
mov (a1+),e6
mov (a1+),e7
mov d0,(a0+)
mov d1,(a0+)
mov e0,(a0+)
mov e1,(a0+)
mov e4,(a0+)
mov e5,(a0+)
mov e6,(a0+)
mov e7,(a0+)
sub d3,d2
bcc memcpy_4_loop
movm (sp),[exreg1]
add d3,d2
beq memcpy_4_no_remainder
memcpy_4_remainder:
# cut 4-7 words down to 0-3
cmp +16,d2
bcs memcpy_4_three_or_fewer_words
mov (a1+),d0
mov (a1+),d1
mov (a1+),e0
mov (a1+),e1
mov d0,(a0+)
mov d1,(a0+)
mov e0,(a0+)
mov e1,(a0+)
add -16,d2
beq memcpy_4_no_remainder
# copy the remaining 1, 2 or 3 words
memcpy_4_three_or_fewer_words:
cmp +8,d2
bcs memcpy_4_one_word
beq memcpy_4_two_words
mov (a1+),d0
mov d0,(a0+)
memcpy_4_two_words:
mov (a1+),d0
mov d0,(a0+)
memcpy_4_one_word:
mov (a1+),d0
mov d0,(a0+)
memcpy_4_no_remainder:
# check we copied the correct amount
# TODO: REMOVE CHECK
sub e3,a0,d2
mov (20,sp),d1
cmp d2,d1
beq memcpy_done
break
break
break
memcpy_done:
mov e3,a0
ret [d2,d3],8
# handle misaligned copying
memcpy_1:
add -1,d2
mov +1,d3
setlb # setlb requires the next insns
# to occupy exactly 4 bytes
sub d3,d2
movbu (a1),d0
movbu d0,(a0)
add_add d3,a1,d3,a0
lcc
mov e3,a0
ret [d2,d3],8
memcpy_end:
.size memcpy, memcpy_end-memcpy
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