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/* Optimized memset implementation for PowerPC.
Copyright (C) 1997 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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