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/* Optimized memset implementation for PowerPC.
Copyright (C) 1997, 1999 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <sysdep.h>
EALIGN(memset,5,1)
/* __ptr_t [r3] memset (__ptr_t s [r3], int c [r4], size_t n [r5]));
Returns 's'.
The memset is done in three sizes: byte (8 bits), word (32 bits),
cache line (256 bits). There is a special case for setting cache lines
to 0, to take advantage of the dcbz instruction.
r6: current address we are storing at
r7: number of bytes we are setting now (when aligning) */
/* take care of case for size <= 4 */
cmplwi cr1,r5,4
andi. r7,r3,3
mr r6,r3
ble- cr1,L(small)
/* align to word boundary */
cmplwi cr5,r5,31
rlwimi r4,r4,8,16,23
beq+ L(aligned) # 8th instruction from .align
mtcrf 0x01,r3
subfic r7,r7,4
add r6,r6,r7
sub r5,r5,r7
bf+ 31,0f
stb r4,0(r3)
bt 30,L(aligned)
0: sth r4,-2(r6) # 16th instruction from .align
/* take care of case for size < 31 */
L(aligned):
mtcrf 0x01,r5
rlwimi r4,r4,16,0,15
ble cr5,L(medium)
/* align to cache line boundary... */
andi. r7,r6,0x1C
subfic r7,r7,0x20
beq L(caligned)
mtcrf 0x01,r7
add r6,r6,r7
sub r5,r5,r7
cmplwi cr1,r7,0x10
mr r8,r6
bf 28,1f
stw r4,-4(r8)
stwu r4,-8(r8)
1: blt cr1,2f
stw r4,-4(r8) # 32nd instruction from .align
stw r4,-8(r8)
stw r4,-12(r8)
stwu r4,-16(r8)
2: bf 29,L(caligned)
stw r4,-4(r8)
/* now aligned to a cache line. */
L(caligned):
cmplwi cr1,r4,0
clrrwi. r7,r5,5
mtcrf 0x01,r5 # 40th instruction from .align
beq cr1,L(zloopstart) # special case for clearing memory using dcbz
srwi r0,r7,5
mtctr r0
beq L(medium) # we may not actually get to do a full line
clrlwi. r5,r5,27
add r6,r6,r7
0: li r8,-0x40
bdz L(cloopdone) # 48th instruction from .align
3: dcbz r8,r6
stw r4,-4(r6)
stw r4,-8(r6)
stw r4,-12(r6)
stw r4,-16(r6)
nop # let 601 fetch last 4 instructions of loop
stw r4,-20(r6)
stw r4,-24(r6) # 56th instruction from .align
nop # let 601 fetch first 8 instructions of loop
stw r4,-28(r6)
stwu r4,-32(r6)
bdnz 3b
L(cloopdone):
stw r4,-4(r6)
stw r4,-8(r6)
stw r4,-12(r6)
stw r4,-16(r6) # 64th instruction from .align
stw r4,-20(r6)
cmplwi cr1,r5,16
stw r4,-24(r6)
stw r4,-28(r6)
stwu r4,-32(r6)
beqlr
add r6,r6,r7
b L(medium_tail2) # 72nd instruction from .align
.align 5
nop
/* Clear lines of memory in 128-byte chunks. */
L(zloopstart):
clrlwi r5,r5,27
mtcrf 0x02,r7
srwi. r0,r7,7
mtctr r0
li r7,0x20
li r8,-0x40
cmplwi cr1,r5,16 # 8
bf 26,0f
dcbz 0,r6
addi r6,r6,0x20
0: li r9,-0x20
bf 25,1f
dcbz 0,r6
dcbz r7,r6
addi r6,r6,0x40 # 16
1: cmplwi cr5,r5,0
beq L(medium)
L(zloop):
dcbz 0,r6
dcbz r7,r6
addi r6,r6,0x80
dcbz r8,r6
dcbz r9,r6
bdnz L(zloop)
beqlr cr5
b L(medium_tail2)
.align 5
L(small):
/* Memset of 4 bytes or less. */
cmplwi cr5,r5,1
cmplwi cr1,r5,3
bltlr cr5
stb r4,0(r6)
beqlr cr5
nop
stb r4,1(r6)
bltlr cr1
stb r4,2(r6)
beqlr cr1
nop
stb r4,3(r6)
blr
/* Memset of 0-31 bytes. */
.align 5
L(medium):
cmplwi cr1,r5,16
L(medium_tail2):
add r6,r6,r5
L(medium_tail):
bt- 31,L(medium_31t)
bt- 30,L(medium_30t)
L(medium_30f):
bt- 29,L(medium_29t)
L(medium_29f):
bge- cr1,L(medium_27t)
bflr- 28
stw r4,-4(r6) # 8th instruction from .align
stw r4,-8(r6)
blr
L(medium_31t):
stbu r4,-1(r6)
bf- 30,L(medium_30f)
L(medium_30t):
sthu r4,-2(r6)
bf- 29,L(medium_29f)
L(medium_29t):
stwu r4,-4(r6)
blt- cr1,L(medium_27f) # 16th instruction from .align
L(medium_27t):
stw r4,-4(r6)
stw r4,-8(r6)
stw r4,-12(r6)
stwu r4,-16(r6)
L(medium_27f):
bflr- 28
L(medium_28t):
stw r4,-4(r6)
stw r4,-8(r6)
blr
END(memset)
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