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/* Optimized memcpy implementation for POWER10.
Copyright (C) 2021-2024 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
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#ifndef MEMCPY
# define MEMCPY memcpy
#endif
/* __ptr_t [r3] memcpy (__ptr_t dst [r3], __ptr_t src [r4], size_t len [r5]);
Returns 'dst'. */
.machine power9
ENTRY_TOCLESS (MEMCPY, 5)
CALL_MCOUNT 3
/* Copy up to 16 bytes. */
sldi r6,r5,56 /* Prepare [l|st]xvl counter. */
lxvl v10,r4,r6
stxvl v10,r3,r6
subic. r6,r5,16 /* Return if len <= 16. */
blelr
/* If len >= 256, assume nothing got copied before and copy
again. This might cause issues with overlapped memory, but memcpy
is not expected to treat overlapped memory. */
cmpdi r5,256
bge L(copy_ge_256)
/* 16 < len < 256 and the first 16 bytes have already been copied. */
addi r10,r3,16 /* Keep r3 intact as return value. */
addi r4,r4,16
subi r5,r5,16
b L(copy_lt_256) /* Avoid the main loop if len < 256. */
.p2align 5
L(copy_ge_256):
mr r10,r3 /* Keep r3 intact as return value. */
/* Align dst to 16 bytes. */
andi. r9,r10,0xf
beq L(dst_is_align_16)
lxv v10,0(r4)
subfic r12,r9,16
subf r5,r12,r5
add r4,r4,r12
stxv v10,0(r3)
add r10,r3,r12
L(dst_is_align_16):
srdi r9,r5,7 /* Divide by 128. */
mtctr r9
addi r6,r4,64
addi r7,r10,64
/* Main loop, copy 128 bytes per iteration.
Use r6=src+64 and r7=dest+64 in order to reduce the dependency on
r4 and r10. */
.p2align 5
L(copy_128):
lxv v10, 0(r4)
lxv v11, 16(r4)
lxv v12, 32(r4)
lxv v13, 48(r4)
addi r4,r4,128
stxv v10, 0(r10)
stxv v11, 16(r10)
stxv v12, 32(r10)
stxv v13, 48(r10)
addi r10,r10,128
lxv v10, 0(r6)
lxv v11, 16(r6)
lxv v12, 32(r6)
lxv v13, 48(r6)
addi r6,r6,128
stxv v10, 0(r7)
stxv v11, 16(r7)
stxv v12, 32(r7)
stxv v13, 48(r7)
addi r7,r7,128
bdnz L(copy_128)
clrldi. r5,r5,64-7 /* Have we copied everything? */
beqlr
.p2align 5
L(copy_lt_256):
cmpdi r5,16
ble L(copy_le_16)
srdi. r9,r5,5 /* Divide by 32. */
beq L(copy_lt_32)
mtctr r9
/* Use r6=src+32, r7=dest+32, r8=src+64, r9=dest+64 in order to reduce
the dependency on r4 and r10. */
addi r6,r4,32
addi r7,r10,32
addi r8,r4,64
addi r9,r10,64
.p2align 5
/* Copy 32 bytes at a time, unaligned.
The loop is unrolled 3 times in order to reduce the dependency on
r4 and r10, copying up-to 96 bytes per iteration. */
L(copy_32):
lxv v10, 0(r4)
lxv v11, 16(r4)
stxv v10, 0(r10)
stxv v11, 16(r10)
bdz L(end_copy_32a)
addi r4,r4,96
addi r10,r10,96
lxv v10, 0(r6)
lxv v11, 16(r6)
addi r6,r6,96
stxv v10, 0(r7)
stxv v11, 16(r7)
bdz L(end_copy_32b)
addi r7,r7,96
lxv v12, 0(r8)
lxv v13, 16(r8)
addi r8,r8,96
stxv v12, 0(r9)
stxv v13, 16(r9)
addi r9,r9,96
bdnz L(copy_32)
clrldi. r5,r5,64-5 /* Have we copied everything? */
beqlr
cmpdi r5,16
ble L(copy_le_16)
b L(copy_lt_32)
.p2align 5
L(end_copy_32a):
clrldi. r5,r5,64-5 /* Have we copied everything? */
beqlr
/* 32 bytes have been copied since the last update of r4 and r10. */
addi r4,r4,32
addi r10,r10,32
cmpdi r5,16
ble L(copy_le_16)
b L(copy_lt_32)
.p2align 5
L(end_copy_32b):
clrldi. r5,r5,64-5 /* Have we copied everything? */
beqlr
/* The last iteration of the loop copied 64 bytes. Update r4 and r10
accordingly. */
addi r4,r4,-32
addi r10,r10,-32
cmpdi r5,16
ble L(copy_le_16)
.p2align 5
L(copy_lt_32):
lxv v10, 0(r4)
stxv v10, 0(r10)
addi r4,r4,16
addi r10,r10,16
subi r5,r5,16
.p2align 5
L(copy_le_16):
sldi r6,r5,56
lxvl v10,r4,r6
stxvl v10,r10,r6
blr
END_GEN_TB (MEMCPY,TB_TOCLESS)
libc_hidden_builtin_def (memcpy)
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