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arch/frv/lib/memcpy.S
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Linux-2.6.12-rc2
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/* memcpy.S: optimised assembly memcpy
*
* Copyright (C) 2003 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 License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
.text
.p2align 4
###############################################################################
#
# void *memcpy(void *to, const char *from, size_t count)
#
# - NOTE: must not use any stack. exception detection performs function return
# to caller's fixup routine, aborting the remainder of the copy
#
###############################################################################
.globl memcpy,__memcpy_end
.type memcpy,@function
memcpy:
or.p gr8,gr9,gr4
orcc gr10,gr0,gr0,icc3
or.p gr10,gr4,gr4
beqlr icc3,#0
# optimise based on best common alignment for to, from & count
andicc.p gr4,#0x0f,gr0,icc0
setlos #8,gr11
andicc.p gr4,#0x07,gr0,icc1
beq icc0,#0,memcpy_16
andicc.p gr4,#0x03,gr0,icc0
beq icc1,#0,memcpy_8
andicc.p gr4,#0x01,gr0,icc1
beq icc0,#0,memcpy_4
setlos.p #1,gr11
beq icc1,#0,memcpy_2
# do byte by byte copy
sub.p gr8,gr11,gr3
sub gr9,gr11,gr9
0: ldubu.p @(gr9,gr11),gr4
subicc gr10,#1,gr10,icc0
stbu.p gr4,@(gr3,gr11)
bne icc0,#2,0b
bralr
# do halfword by halfword copy
memcpy_2:
setlos #2,gr11
sub.p gr8,gr11,gr3
sub gr9,gr11,gr9
0: lduhu.p @(gr9,gr11),gr4
subicc gr10,#2,gr10,icc0
sthu.p gr4,@(gr3,gr11)
bne icc0,#2,0b
bralr
# do word by word copy
memcpy_4:
setlos #4,gr11
sub.p gr8,gr11,gr3
sub gr9,gr11,gr9
0: ldu.p @(gr9,gr11),gr4
subicc gr10,#4,gr10,icc0
stu.p gr4,@(gr3,gr11)
bne icc0,#2,0b
bralr
# do double-word by double-word copy
memcpy_8:
sub.p gr8,gr11,gr3
sub gr9,gr11,gr9
0: lddu.p @(gr9,gr11),gr4
subicc gr10,#8,gr10,icc0
stdu.p gr4,@(gr3,gr11)
bne icc0,#2,0b
bralr
# do quad-word by quad-word copy
memcpy_16:
sub.p gr8,gr11,gr3
sub gr9,gr11,gr9
0: lddu @(gr9,gr11),gr4
lddu.p @(gr9,gr11),gr6
subicc gr10,#16,gr10,icc0
stdu gr4,@(gr3,gr11)
stdu.p gr6,@(gr3,gr11)
bne icc0,#2,0b
bralr
__memcpy_end:
.size memcpy, __memcpy_end-memcpy
###############################################################################
#
# copy to/from userspace
# - return the number of bytes that could not be copied (0 on complete success)
#
# long __memcpy_user(void *dst, const void *src, size_t count)
#
###############################################################################
.globl __memcpy_user, __memcpy_user_error_lr, __memcpy_user_error_handler
.type __memcpy_user,@function
__memcpy_user:
movsg lr,gr7
subi.p sp,#8,sp
add gr8,gr10,gr6 ; calculate expected end address
stdi gr6,@(sp,#0)
# abuse memcpy to do the dirty work
call memcpy
__memcpy_user_error_lr:
ldi.p @(sp,#4),gr7
setlos #0,gr8
jmpl.p @(gr7,gr0)
addi sp,#8,sp
# deal any exception generated by memcpy
# GR8 - memcpy's current dest address
# GR11 - memset's step value (index register for store insns)
__memcpy_user_error_handler:
lddi.p @(sp,#0),gr4 ; load GR4 with dst+count, GR5 with ret addr
add gr11,gr3,gr7
sub.p gr4,gr7,gr8
addi sp,#8,sp
jmpl @(gr5,gr0)
.size __memcpy_user, .-__memcpy_user
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