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/* Optimized memset implementation for PowerPC64.
Copyright (C) 1997-2021 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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
/* void * [r3] memset (void *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 (1024 bits). There is a special case for setting cache lines
to 0, to take advantage of the dcbz instruction. */
.machine power4
EALIGN (memset, 5, 0)
CALL_MCOUNT
#define rTMP r0
#define rRTN r3 /* Initial value of 1st argument. */
#define rMEMP0 r3 /* Original value of 1st arg. */
#define rCHR r4 /* Char to set in each byte. */
#define rLEN r5 /* Length of region to set. */
#define rMEMP r6 /* Address at which we are storing. */
#define rALIGN r7 /* Number of bytes we are setting now (when aligning). */
#define rMEMP2 r8
#define rNEG64 r8 /* Constant -64 for clearing with dcbz. */
#define rCLS r8 /* Cache line size (known to be 128). */
#define rCLM r9 /* Cache line size mask to check for cache alignment. */
L(_memset):
/* Take care of case for size <= 4. */
cmplwi cr1, rLEN, 4
andi. rALIGN, rMEMP0, 3
mr rMEMP, rMEMP0
ble- cr1, L(small)
/* Align to word boundary. */
cmplwi cr5, rLEN, 31
insrwi rCHR, rCHR, 8, 16 /* Replicate byte to halfword. */
beq+ L(aligned)
mtcrf 0x01, rMEMP0
subfic rALIGN, rALIGN, 4
add rMEMP, rMEMP, rALIGN
sub rLEN, rLEN, rALIGN
bf+ 31, L(g0)
stb rCHR, 0(rMEMP0)
bt 30, L(aligned)
L(g0):
sth rCHR, -2(rMEMP)
/* Handle the case of size < 31. */
L(aligned):
mtcrf 0x01, rLEN
insrwi rCHR, rCHR, 16, 0 /* Replicate halfword to word. */
ble cr5, L(medium)
/* Align to 32-byte boundary. */
andi. rALIGN, rMEMP, 0x1C
subfic rALIGN, rALIGN, 0x20
beq L(caligned)
mtcrf 0x01, rALIGN
add rMEMP, rMEMP, rALIGN
sub rLEN, rLEN, rALIGN
cmplwi cr1, rALIGN, 0x10
mr rMEMP2, rMEMP
bf 28, L(a1)
stw rCHR, -4(rMEMP2)
stwu rCHR, -8(rMEMP2)
L(a1): blt cr1, L(a2)
stw rCHR, -4(rMEMP2)
stw rCHR, -8(rMEMP2)
stw rCHR, -12(rMEMP2)
stwu rCHR, -16(rMEMP2)
L(a2): bf 29, L(caligned)
stw rCHR, -4(rMEMP2)
/* Now aligned to a 32 byte boundary. */
L(caligned):
cmplwi cr1, rCHR, 0
clrrwi. rALIGN, rLEN, 5
mtcrf 0x01, rLEN
beq cr1, L(zloopstart) /* Special case for clearing memory using dcbz. */
L(nondcbz):
srwi rTMP, rALIGN, 5
mtctr rTMP
beq L(medium) /* We may not actually get to do a full line. */
clrlwi. rLEN, rLEN, 27
add rMEMP, rMEMP, rALIGN
li rNEG64, -0x40
bdz L(cloopdone)
.align 4
L(c3): dcbtst rNEG64, rMEMP
stw rCHR, -4(rMEMP)
stw rCHR, -8(rMEMP)
stw rCHR, -12(rMEMP)
stw rCHR, -16(rMEMP)
stw rCHR, -20(rMEMP)
stw rCHR, -24(rMEMP)
stw rCHR, -28(rMEMP)
stwu rCHR, -32(rMEMP)
bdnz L(c3)
L(cloopdone):
stw rCHR, -4(rMEMP)
stw rCHR, -8(rMEMP)
stw rCHR, -12(rMEMP)
stw rCHR, -16(rMEMP)
cmplwi cr1, rLEN, 16
stw rCHR, -20(rMEMP)
stw rCHR, -24(rMEMP)
stw rCHR, -28(rMEMP)
stwu rCHR, -32(rMEMP)
beqlr
add rMEMP, rMEMP, rALIGN
b L(medium_tail2)
.align 5
/* Clear lines of memory in 128-byte chunks. */
L(zloopstart):
/* If the remaining length is less the 32 bytes, don't bother getting
the cache line size. */
beq L(medium)
li rCLS,128 /* cache line size is 128 */
dcbt 0,rMEMP
L(getCacheAligned):
cmplwi cr1,rLEN,32
andi. rTMP,rMEMP,127
blt cr1,L(handletail32)
beq L(cacheAligned)
addi rMEMP,rMEMP,32
addi rLEN,rLEN,-32
stw rCHR,-32(rMEMP)
stw rCHR,-28(rMEMP)
stw rCHR,-24(rMEMP)
stw rCHR,-20(rMEMP)
stw rCHR,-16(rMEMP)
stw rCHR,-12(rMEMP)
stw rCHR,-8(rMEMP)
stw rCHR,-4(rMEMP)
b L(getCacheAligned)
/* Now we are aligned to the cache line and can use dcbz. */
.align 4
L(cacheAligned):
cmplw cr1,rLEN,rCLS
blt cr1,L(handletail32)
dcbz 0,rMEMP
subf rLEN,rCLS,rLEN
add rMEMP,rMEMP,rCLS
b L(cacheAligned)
/* We are here because the cache line size was set and the remainder
(rLEN) is less than the actual cache line size.
So set up the preconditions for L(nondcbz) and go there. */
L(handletail32):
clrrwi. rALIGN, rLEN, 5
b L(nondcbz)
.align 5
L(small):
/* Memset of 4 bytes or less. */
cmplwi cr5, rLEN, 1
cmplwi cr1, rLEN, 3
bltlr cr5
stb rCHR, 0(rMEMP)
beqlr cr5
stb rCHR, 1(rMEMP)
bltlr cr1
stb rCHR, 2(rMEMP)
beqlr cr1
stb rCHR, 3(rMEMP)
blr
/* Memset of 0-31 bytes. */
.align 5
L(medium):
cmplwi cr1, rLEN, 16
L(medium_tail2):
add rMEMP, rMEMP, rLEN
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 rCHR, -4(rMEMP)
stw rCHR, -8(rMEMP)
blr
L(medium_31t):
stbu rCHR, -1(rMEMP)
bf- 30, L(medium_30f)
L(medium_30t):
sthu rCHR, -2(rMEMP)
bf- 29, L(medium_29f)
L(medium_29t):
stwu rCHR, -4(rMEMP)
blt- cr1, L(medium_27f)
L(medium_27t):
stw rCHR, -4(rMEMP)
stw rCHR, -8(rMEMP)
stw rCHR, -12(rMEMP)
stwu rCHR, -16(rMEMP)
L(medium_27f):
bflr- 28
L(medium_28t):
stw rCHR, -4(rMEMP)
stw rCHR, -8(rMEMP)
blr
END (memset)
libc_hidden_builtin_def (memset)
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