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/* Optimized memset implementation for PowerPC32/POWER7.
Copyright (C) 2010-2019 Free Software Foundation, Inc.
Contributed by Luis Machado <luisgpm@br.ibm.com>.
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'. */
.machine power7
EALIGN (memset, 5, 0)
CALL_MCOUNT
.align 4
L(_memset):
cmplwi cr7,5,31
cmplwi cr6,5,8
mr 10,3 /* Save original argument for later. */
mr 7,1 /* Save original r1 for later. */
cfi_offset(31,-8)
/* Replicate byte to word. */
insrwi 4,4,8,16
insrwi 4,4,16,0
ble cr6,L(small) /* If length <= 8, use short copy code. */
neg 0,3
ble cr7,L(medium) /* If length < 32, use medium copy code. */
/* Save our word twice to create a doubleword that we will later
copy to a FPR. */
stwu 1,-32(1)
andi. 11,10,7 /* Check alignment of DST. */
mr 12,5
stw 4,24(1)
stw 4,28(1)
beq L(big_aligned)
clrlwi 0,0,29
mtocrf 0x01,0
subf 5,0,5
/* Get DST aligned to 8 bytes. */
1: bf 31,2f
stb 4,0(10)
addi 10,10,1
2: bf 30,4f
sth 4,0(10)
addi 10,10,2
4: bf 29,L(big_aligned)
stw 4,0(10)
addi 10,10,4
.align 4
L(big_aligned):
cmplwi cr5,5,255
li 0,32
cmplwi cr1,5,160
dcbtst 0,10
cmplwi cr6,4,0
srwi 9,5,3 /* Number of full doublewords remaining. */
crand 27,26,21
mtocrf 0x01,9
bt 27,L(huge)
/* From this point on, we'll copy 32+ bytes and the value
isn't 0 (so we can't use dcbz). */
srwi 8,5,5
clrlwi 11,5,29
cmplwi cr6,11,0
cmplwi cr1,9,4
mtctr 8
/* Copy 1~3 doublewords so the main loop starts
at a multiple of 32 bytes. */
bf 30,1f
stw 4,0(10)
stw 4,4(10)
stw 4,8(10)
stw 4,12(10)
addi 10,10,16
bf 31,L(big_loop)
stw 4,0(10)
stw 4,4(10)
addi 10,10,8
mr 12,10
blt cr1,L(tail_bytes)
b L(big_loop)
.align 4
1: /* Copy 1 doubleword. */
bf 31,L(big_loop)
stw 4,0(10)
stw 4,4(10)
addi 10,10,8
/* First use a 32-bytes loop with stw's to try and avoid the LHS due
to the lfd we will do next. Also, ping-pong through r10 and r12
to avoid AGEN delays. */
.align 4
L(big_loop):
addi 12,10,32
stw 4,0(10)
stw 4,4(10)
stw 4,8(10)
stw 4,12(10)
stw 4,16(10)
stw 4,20(10)
stw 4,24(10)
stw 4,28(10)
bdz L(tail_bytes)
addi 10,10,64
stw 4,0(12)
stw 4,4(12)
stw 4,8(12)
stw 4,12(12)
stw 4,16(12)
stw 4,20(12)
stw 4,24(12)
stw 4,28(12)
bdnz L(big_loop_fast_setup)
mr 12,10
b L(tail_bytes)
/* Now that we're probably past the LHS window, use the VSX to
speed up the loop. */
L(big_loop_fast_setup):
li 11,24
li 6,16
lxvdsx 4,1,11
.align 4
L(big_loop_fast):
addi 12,10,32
stxvd2x 4,0,10
stxvd2x 4,10,6
bdz L(tail_bytes)
addi 10,10,64
stxvd2x 4,0,12
stxvd2x 4,12,6
bdnz L(big_loop_fast)
mr 12,10
.align 4
L(tail_bytes):
/* Check for tail bytes. */
mr 1,7 /* Restore r1. */
beqlr cr6
clrlwi 0,5,29
mtocrf 0x01,0
/* At this point we have a tail of 0-7 bytes and we know that the
destination is doubleword-aligned. */
4: /* Copy 4 bytes. */
bf 29,2f
stw 4,0(12)
addi 12,12,4
2: /* Copy 2 bytes. */
bf 30,1f
sth 4,0(12)
addi 12,12,2
1: /* Copy 1 byte. */
bflr 31
stb 4,0(12)
blr
/* Special case when value is 0 and we have a long length to deal
with. Use dcbz to zero out 128-bytes at a time. Before using
dcbz though, we need to get the destination 128-bytes aligned. */
.align 4
L(huge):
lfd 4,24(1)
andi. 11,10,127
neg 0,10
beq L(huge_aligned)
clrlwi 0,0,25
subf 5,0,5
srwi 0,0,3
mtocrf 0x01,0
/* Get DST aligned to 128 bytes. */
8: bf 28,4f
stfd 4,0(10)
stfd 4,8(10)
stfd 4,16(10)
stfd 4,24(10)
stfd 4,32(10)
stfd 4,40(10)
stfd 4,48(10)
stfd 4,56(10)
addi 10,10,64
.align 4
4: bf 29,2f
stfd 4,0(10)
stfd 4,8(10)
stfd 4,16(10)
stfd 4,24(10)
addi 10,10,32
.align 4
2: bf 30,1f
stfd 4,0(10)
stfd 4,8(10)
addi 10,10,16
.align 4
1: bf 31,L(huge_aligned)
stfd 4,0(10)
addi 10,10,8
L(huge_aligned):
srwi 8,5,7
clrlwi 11,5,25
cmplwi cr6,11,0
mtctr 8
/* Copies 128-bytes at a time. */
.align 4
L(huge_loop):
dcbz 0,10
addi 10,10,128
bdnz L(huge_loop)
/* We have a tail of 0~127 bytes to handle. */
mr 1,7 /* Restore r1. */
beqlr cr6
subf 9,3,10
subf 5,9,12
srwi 8,5,3
cmplwi cr6,8,0
mtocrf 0x01,8
/* We have a tail o 1~127 bytes. Copy up to 15 doublewords for
speed. We'll handle the resulting tail bytes later. */
beq cr6,L(tail)
8: bf 28,4f
stfd 4,0(10)
stfd 4,8(10)
stfd 4,16(10)
stfd 4,24(10)
stfd 4,32(10)
stfd 4,40(10)
stfd 4,48(10)
stfd 4,56(10)
addi 10,10,64
.align 4
4: bf 29,2f
stfd 4,0(10)
stfd 4,8(10)
stfd 4,16(10)
stfd 4,24(10)
addi 10,10,32
.align 4
2: bf 30,1f
stfd 4,0(10)
stfd 4,8(10)
addi 10,10,16
.align 4
1: bf 31,L(tail)
stfd 4,0(10)
addi 10,10,8
/* Handle the rest of the tail bytes here. */
L(tail):
mtocrf 0x01,5
.align 4
4: bf 29,2f
stw 4,0(10)
addi 10,10,4
.align 4
2: bf 30,1f
sth 4,0(10)
addi 10,10,2
.align 4
1: bflr 31
stb 4,0(10)
blr
/* Expanded tree to copy tail bytes without increments. */
.align 4
L(copy_tail):
bf 29,L(FXX)
stw 4,0(10)
bf 30,L(TFX)
sth 4,4(10)
bflr 31
stb 4,6(10)
blr
.align 4
L(FXX): bf 30,L(FFX)
sth 4,0(10)
bflr 31
stb 4,2(10)
blr
.align 4
L(TFX): bflr 31
stb 4,4(10)
blr
.align 4
L(FFX): bflr 31
stb 4,0(10)
blr
/* Handle copies of 9~31 bytes. */
.align 4
L(medium):
/* At least 9 bytes to go. */
andi. 11,10,3
clrlwi 0,0,30
beq L(medium_aligned)
/* Force 4-bytes alignment for DST. */
mtocrf 0x01,0
subf 5,0,5
1: /* Copy 1 byte. */
bf 31,2f
stb 4,0(10)
addi 10,10,1
2: /* Copy 2 bytes. */
bf 30,L(medium_aligned)
sth 4,0(10)
addi 10,10,2
.align 4
L(medium_aligned):
/* At least 6 bytes to go, and DST is word-aligned. */
cmplwi cr1,5,16
mtocrf 0x01,5
blt cr1,8f
/* Copy 16 bytes. */
stw 4,0(10)
stw 4,4(10)
stw 4,8(10)
stw 4,12(10)
addi 10,10,16
8: /* Copy 8 bytes. */
bf 28,4f
stw 4,0(10)
stw 4,4(10)
addi 10,10,8
4: /* Copy 4 bytes. */
bf 29,2f
stw 4,0(10)
addi 10,10,4
2: /* Copy 2-3 bytes. */
bf 30,1f
sth 4,0(10)
addi 10,10,2
1: /* Copy 1 byte. */
bflr 31
stb 4,0(10)
blr
/* Handles copies of 0~8 bytes. */
.align 4
L(small):
mtocrf 0x01,5
bne cr6,L(copy_tail)
stw 4,0(10)
stw 4,4(10)
blr
END (memset)
libc_hidden_builtin_def (memset)
|
