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/* Optimized memset implementation for PowerPC.
Copyright (C) 1997-2025 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>
#include <rtld-global-offsets.h>
/* void * [r3] memset (void *s [r3], int c [r4], size_t n [r5]));
Returns 's'.
The memset is done in four sizes: byte (8 bits), word (32 bits),
32-byte blocks (256 bits) and cache line size (128, 256, 1024 bits).
There is a special case for setting whole cache lines to 0, which
takes advantage of the dcbz instruction. */
.section ".text"
EALIGN (memset, 5, 1)
#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 rPOS32 r7 /* constant +32 for clearing with dcbz */
#define rNEG64 r8 /* constant -64 for clearing with dcbz */
#define rNEG32 r9 /* constant -32 for clearing with dcbz */
#define rGOT r9 /* Address of the Global Offset Table. */
#define rCLS r8 /* Cache line size obtained from static. */
#define rCLM r9 /* Cache line size mask to check for cache alignment. */
/* 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
rlwimi rCHR, rCHR, 8, 16, 23
beq+ L(aligned) /* 8th instruction from .align */
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) /* 16th instruction from .align */
/* take care of case for size < 31 */
L(aligned):
mtcrf 0x01, rLEN
rlwimi rCHR, rCHR, 16, 0, 15
ble cr5, L(medium)
/* align to cache line 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) /* 32nd instruction from .align */
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 cache line. */
L(caligned):
cmplwi cr1, rCHR, 0
clrrwi. rALIGN, rLEN, 5
mtcrf 0x01, rLEN /* 40th instruction from .align */
/* Check if we can use the special case for clearing memory using dcbz.
This requires that we know the correct cache line size for this
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