mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-28 13:31:13 +00:00
482 lines
12 KiB
ArmAsm
482 lines
12 KiB
ArmAsm
/* Optimized memcpy implementation for PowerPC32 on PowerPC64.
|
|
Copyright (C) 2003-2015 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>
|
|
|
|
/* __ptr_t [r3] memcpy (__ptr_t dst [r3], __ptr_t src [r4], size_t len [r5]);
|
|
Returns 'dst'.
|
|
|
|
Memcpy handles short copies (< 32-bytes) using a binary move blocks
|
|
(no loops) of lwz/stw. The tail (remaining 1-3) bytes is handled
|
|
with the appropriate combination of byte and halfword load/stores.
|
|
There is minimal effort to optimize the alignment of short moves.
|
|
|
|
Longer moves (>= 32-bytes) justify the effort to get at least the
|
|
destination word (4-byte) aligned. Further optimization is
|
|
possible when both source and destination are word aligned.
|
|
Each case has an optimized unrolled loop. */
|
|
|
|
.machine power4
|
|
EALIGN (memcpy, 5, 0)
|
|
CALL_MCOUNT
|
|
|
|
stwu 1,-32(1)
|
|
cfi_adjust_cfa_offset(32)
|
|
stw 30,20(1)
|
|
cfi_offset(30,(20-32))
|
|
mr 30,3
|
|
cmplwi cr1,5,31
|
|
stw 31,24(1)
|
|
cfi_offset(31,(24-32))
|
|
neg 0,3
|
|
andi. 11,3,3 /* check alignment of dst. */
|
|
clrlwi 0,0,30 /* Number of bytes until the 1st word of dst. */
|
|
clrlwi 10,4,30 /* check alignment of src. */
|
|
cmplwi cr6,5,8
|
|
ble- cr1,.L2 /* If move < 32 bytes use short move code. */
|
|
cmplw cr6,10,11
|
|
mr 12,4
|
|
srwi 9,5,2 /* Number of full words remaining. */
|
|
mtcrf 0x01,0
|
|
mr 31,5
|
|
beq .L0
|
|
|
|
subf 31,0,5
|
|
/* Move 0-3 bytes as needed to get the destination word aligned. */
|
|
1: bf 31,2f
|
|
lbz 6,0(12)
|
|
addi 12,12,1
|
|
stb 6,0(3)
|
|
addi 3,3,1
|
|
2: bf 30,0f
|
|
lhz 6,0(12)
|
|
addi 12,12,2
|
|
sth 6,0(3)
|
|
addi 3,3,2
|
|
0:
|
|
clrlwi 10,12,30 /* check alignment of src again. */
|
|
srwi 9,31,2 /* Number of full words remaining. */
|
|
|
|
/* Copy words from source to destination, assuming the destination is
|
|
aligned on a word boundary.
|
|
|
|
At this point we know there are at least 25 bytes left (32-7) to copy.
|
|
The next step is to determine if the source is also word aligned.
|
|
If not branch to the unaligned move code at .L6. which uses
|
|
a load, shift, store strategy.
|
|
|
|
Otherwise source and destination are word aligned, and we can use
|
|
the optimized word copy loop. */
|
|
.L0:
|
|
clrlwi 11,31,30 /* calculate the number of tail bytes */
|
|
mtcrf 0x01,9
|
|
bne- cr6,.L6 /* If source is not word aligned. */
|
|
|
|
/* Move words where destination and source are word aligned.
|
|
Use an unrolled loop to copy 4 words (16-bytes) per iteration.
|
|
If the copy is not an exact multiple of 16 bytes, 1-3
|
|
words are copied as needed to set up the main loop. After
|
|
the main loop exits there may be a tail of 1-3 bytes. These bytes are
|
|
copied a halfword/byte at a time as needed to preserve alignment. */
|
|
|
|
srwi 8,31,4 /* calculate the 16 byte loop count */
|
|
cmplwi cr1,9,4
|
|
cmplwi cr6,11,0
|
|
mr 11,12
|
|
|
|
bf 30,1f
|
|
lwz 6,0(12)
|
|
lwz 7,4(12)
|
|
addi 11,12,8
|
|
mtctr 8
|
|
stw 6,0(3)
|
|
stw 7,4(3)
|
|
addi 10,3,8
|
|
bf 31,4f
|
|
lwz 0,8(12)
|
|
stw 0,8(3)
|
|
blt cr1,3f
|
|
addi 11,12,12
|
|
addi 10,3,12
|
|
b 4f
|
|
.align 4
|
|
1:
|
|
mr 10,3
|
|
mtctr 8
|
|
bf 31,4f
|
|
lwz 6,0(12)
|
|
addi 11,12,4
|
|
stw 6,0(3)
|
|
addi 10,3,4
|
|
|
|
.align 4
|
|
4:
|
|
lwz 6,0(11)
|
|
lwz 7,4(11)
|
|
lwz 8,8(11)
|
|
lwz 0,12(11)
|
|
stw 6,0(10)
|
|
stw 7,4(10)
|
|
stw 8,8(10)
|
|
stw 0,12(10)
|
|
addi 11,11,16
|
|
addi 10,10,16
|
|
bdnz 4b
|
|
3:
|
|
clrrwi 0,31,2
|
|
mtcrf 0x01,31
|
|
beq cr6,0f
|
|
.L9:
|
|
add 3,3,0
|
|
add 12,12,0
|
|
|
|
/* At this point we have a tail of 0-3 bytes and we know that the
|
|
destination is word aligned. */
|
|
2: bf 30,1f
|
|
lhz 6,0(12)
|
|
addi 12,12,2
|
|
sth 6,0(3)
|
|
addi 3,3,2
|
|
1: bf 31,0f
|
|
lbz 6,0(12)
|
|
stb 6,0(3)
|
|
0:
|
|
/* Return original dst pointer. */
|
|
mr 3,30
|
|
lwz 30,20(1)
|
|
lwz 31,24(1)
|
|
addi 1,1,32
|
|
blr
|
|
|
|
/* Copy up to 31 bytes. This is divided into two cases 0-8 bytes and
|
|
9-31 bytes. Each case is handled without loops, using binary
|
|
(1,2,4,8) tests.
|
|
|
|
In the short (0-8 byte) case no attempt is made to force alignment
|
|
of either source or destination. The hardware will handle the
|
|
unaligned load/stores with small delays for crossing 32- 64-byte, and
|
|
4096-byte boundaries. Since these short moves are unlikely to be
|
|
unaligned or cross these boundaries, the overhead to force
|
|
alignment is not justified.
|
|
|
|
The longer (9-31 byte) move is more likely to cross 32- or 64-byte
|
|
boundaries. Since only loads are sensitive to the 32-/64-byte
|
|
boundaries it is more important to align the source than the
|
|
destination. If the source is not already word aligned, we first
|
|
move 1-3 bytes as needed. While the destination and stores may
|
|
still be unaligned, this is only an issue for page (4096 byte
|
|
boundary) crossing, which should be rare for these short moves.
|
|
The hardware handles this case automatically with a small delay. */
|
|
|
|
.align 4
|
|
.L2:
|
|
mtcrf 0x01,5
|
|
neg 8,4
|
|
clrrwi 11,4,2
|
|
andi. 0,8,3
|
|
ble cr6,.LE8 /* Handle moves of 0-8 bytes. */
|
|
/* At least 9 bytes left. Get the source word aligned. */
|
|
cmplwi cr1,5,16
|
|
mr 10,5
|
|
mr 12,4
|
|
cmplwi cr6,0,2
|
|
beq .L3 /* If the source is already word aligned skip this. */
|
|
/* Copy 1-3 bytes to get source address word aligned. */
|
|
lwz 6,0(11)
|
|
subf 10,0,5
|
|
add 12,4,0
|
|
blt cr6,5f
|
|
srwi 7,6,16
|
|
bgt cr6,3f
|
|
#ifdef __LITTLE_ENDIAN__
|
|
sth 7,0(3)
|
|
#else
|
|
sth 6,0(3)
|
|
#endif
|
|
b 7f
|
|
.align 4
|
|
3:
|
|
#ifdef __LITTLE_ENDIAN__
|
|
rotlwi 6,6,24
|
|
stb 6,0(3)
|
|
sth 7,1(3)
|
|
#else
|
|
stb 7,0(3)
|
|
sth 6,1(3)
|
|
#endif
|
|
b 7f
|
|
.align 4
|
|
5:
|
|
#ifdef __LITTLE_ENDIAN__
|
|
rotlwi 6,6,8
|
|
#endif
|
|
stb 6,0(3)
|
|
7:
|
|
cmplwi cr1,10,16
|
|
add 3,3,0
|
|
mtcrf 0x01,10
|
|
.align 4
|
|
.L3:
|
|
/* At least 6 bytes left and the source is word aligned. */
|
|
blt cr1,8f
|
|
16: /* Move 16 bytes. */
|
|
lwz 6,0(12)
|
|
lwz 7,4(12)
|
|
stw 6,0(3)
|
|
lwz 6,8(12)
|
|
stw 7,4(3)
|
|
lwz 7,12(12)
|
|
addi 12,12,16
|
|
stw 6,8(3)
|
|
stw 7,12(3)
|
|
addi 3,3,16
|
|
8: /* Move 8 bytes. */
|
|
bf 28,4f
|
|
lwz 6,0(12)
|
|
lwz 7,4(12)
|
|
addi 12,12,8
|
|
stw 6,0(3)
|
|
stw 7,4(3)
|
|
addi 3,3,8
|
|
4: /* Move 4 bytes. */
|
|
bf 29,2f
|
|
lwz 6,0(12)
|
|
addi 12,12,4
|
|
stw 6,0(3)
|
|
addi 3,3,4
|
|
2: /* Move 2-3 bytes. */
|
|
bf 30,1f
|
|
lhz 6,0(12)
|
|
sth 6,0(3)
|
|
bf 31,0f
|
|
lbz 7,2(12)
|
|
stb 7,2(3)
|
|
mr 3,30
|
|
lwz 30,20(1)
|
|
addi 1,1,32
|
|
blr
|
|
1: /* Move 1 byte. */
|
|
bf 31,0f
|
|
lbz 6,0(12)
|
|
stb 6,0(3)
|
|
0:
|
|
/* Return original dst pointer. */
|
|
mr 3,30
|
|
lwz 30,20(1)
|
|
addi 1,1,32
|
|
blr
|
|
|
|
/* Special case to copy 0-8 bytes. */
|
|
.align 4
|
|
.LE8:
|
|
mr 12,4
|
|
bne cr6,4f
|
|
lwz 6,0(4)
|
|
lwz 7,4(4)
|
|
stw 6,0(3)
|
|
stw 7,4(3)
|
|
/* Return original dst pointer. */
|
|
mr 3,30
|
|
lwz 30,20(1)
|
|
addi 1,1,32
|
|
blr
|
|
.align 4
|
|
4: bf 29,2b
|
|
lwz 6,0(4)
|
|
stw 6,0(3)
|
|
6:
|
|
bf 30,5f
|
|
lhz 7,4(4)
|
|
sth 7,4(3)
|
|
bf 31,0f
|
|
lbz 8,6(4)
|
|
stb 8,6(3)
|
|
mr 3,30
|
|
lwz 30,20(1)
|
|
addi 1,1,32
|
|
blr
|
|
.align 4
|
|
5:
|
|
bf 31,0f
|
|
lbz 6,4(4)
|
|
stb 6,4(3)
|
|
.align 4
|
|
0:
|
|
/* Return original dst pointer. */
|
|
mr 3,30
|
|
lwz 30,20(1)
|
|
addi 1,1,32
|
|
blr
|
|
|
|
.align 4
|
|
.L6:
|
|
|
|
/* Copy words where the destination is aligned but the source is
|
|
not. Use aligned word loads from the source, shifted to realign
|
|
the data, to allow aligned destination stores.
|
|
Use an unrolled loop to copy 4 words (16-bytes) per iteration.
|
|
A single word is retained for storing at loop exit to avoid walking
|
|
off the end of a page within the loop.
|
|
If the copy is not an exact multiple of 16 bytes, 1-3
|
|
words are copied as needed to set up the main loop. After
|
|
the main loop exits there may be a tail of 1-3 bytes. These bytes are
|
|
copied a halfword/byte at a time as needed to preserve alignment. */
|
|
|
|
|
|
cmplwi cr6,11,0 /* are there tail bytes left ? */
|
|
subf 5,10,12 /* back up src pointer to prev word alignment */
|
|
slwi 10,10,3 /* calculate number of bits to shift 1st word left */
|
|
addi 11,9,-1 /* we move one word after the loop */
|
|
srwi 8,11,2 /* calculate the 16 byte loop count */
|
|
lwz 6,0(5) /* load 1st src word into R6 */
|
|
mr 4,3
|
|
lwz 7,4(5) /* load 2nd src word into R7 */
|
|
mtcrf 0x01,11
|
|
subfic 9,10,32 /* number of bits to shift 2nd word right */
|
|
mtctr 8
|
|
bf 30,1f
|
|
|
|
/* there are at least two words to copy, so copy them */
|
|
#ifdef __LITTLE_ENDIAN__
|
|
srw 0,6,10
|
|
slw 8,7,9
|
|
#else
|
|
slw 0,6,10 /* shift 1st src word to left align it in R0 */
|
|
srw 8,7,9 /* shift 2nd src word to right align it in R8 */
|
|
#endif
|
|
or 0,0,8 /* or them to get word to store */
|
|
lwz 6,8(5) /* load the 3rd src word */
|
|
stw 0,0(4) /* store the 1st dst word */
|
|
#ifdef __LITTLE_ENDIAN__
|
|
srw 0,7,10
|
|
slw 8,6,9
|
|
#else
|
|
slw 0,7,10 /* now left align 2nd src word into R0 */
|
|
srw 8,6,9 /* shift 3rd src word to right align it in R8 */
|
|
#endif
|
|
or 0,0,8 /* or them to get word to store */
|
|
lwz 7,12(5)
|
|
stw 0,4(4) /* store the 2nd dst word */
|
|
addi 4,4,8
|
|
addi 5,5,16
|
|
bf 31,4f
|
|
/* there is a third word to copy, so copy it */
|
|
#ifdef __LITTLE_ENDIAN__
|
|
srw 0,6,10
|
|
slw 8,7,9
|
|
#else
|
|
slw 0,6,10 /* shift 3rd src word to left align it in R0 */
|
|
srw 8,7,9 /* shift 4th src word to right align it in R8 */
|
|
#endif
|
|
or 0,0,8 /* or them to get word to store */
|
|
stw 0,0(4) /* store 3rd dst word */
|
|
mr 6,7
|
|
lwz 7,0(5)
|
|
addi 5,5,4
|
|
addi 4,4,4
|
|
b 4f
|
|
.align 4
|
|
1:
|
|
#ifdef __LITTLE_ENDIAN__
|
|
srw 0,6,10
|
|
slw 8,7,9
|
|
#else
|
|
slw 0,6,10 /* shift 1st src word to left align it in R0 */
|
|
srw 8,7,9 /* shift 2nd src word to right align it in R8 */
|
|
#endif
|
|
addi 5,5,8
|
|
or 0,0,8 /* or them to get word to store */
|
|
bf 31,4f
|
|
mr 6,7
|
|
lwz 7,0(5)
|
|
addi 5,5,4
|
|
stw 0,0(4) /* store the 1st dst word */
|
|
addi 4,4,4
|
|
|
|
.align 4
|
|
4:
|
|
/* copy 16 bytes at a time */
|
|
#ifdef __LITTLE_ENDIAN__
|
|
srw 0,6,10
|
|
slw 8,7,9
|
|
#else
|
|
slw 0,6,10
|
|
srw 8,7,9
|
|
#endif
|
|
or 0,0,8
|
|
lwz 6,0(5)
|
|
stw 0,0(4)
|
|
#ifdef __LITTLE_ENDIAN__
|
|
srw 0,7,10
|
|
slw 8,6,9
|
|
#else
|
|
slw 0,7,10
|
|
srw 8,6,9
|
|
#endif
|
|
or 0,0,8
|
|
lwz 7,4(5)
|
|
stw 0,4(4)
|
|
#ifdef __LITTLE_ENDIAN__
|
|
srw 0,6,10
|
|
slw 8,7,9
|
|
#else
|
|
slw 0,6,10
|
|
srw 8,7,9
|
|
#endif
|
|
or 0,0,8
|
|
lwz 6,8(5)
|
|
stw 0,8(4)
|
|
#ifdef __LITTLE_ENDIAN__
|
|
srw 0,7,10
|
|
slw 8,6,9
|
|
#else
|
|
slw 0,7,10
|
|
srw 8,6,9
|
|
#endif
|
|
or 0,0,8
|
|
lwz 7,12(5)
|
|
stw 0,12(4)
|
|
addi 5,5,16
|
|
addi 4,4,16
|
|
bdnz+ 4b
|
|
8:
|
|
/* calculate and store the final word */
|
|
#ifdef __LITTLE_ENDIAN__
|
|
srw 0,6,10
|
|
slw 8,7,9
|
|
#else
|
|
slw 0,6,10
|
|
srw 8,7,9
|
|
#endif
|
|
or 0,0,8
|
|
stw 0,0(4)
|
|
3:
|
|
clrrwi 0,31,2
|
|
mtcrf 0x01,31
|
|
bne cr6,.L9 /* If the tail is 0 bytes we are done! */
|
|
|
|
/* Return original dst pointer. */
|
|
mr 3,30
|
|
lwz 30,20(1)
|
|
lwz 31,24(1)
|
|
addi 1,1,32
|
|
blr
|
|
END (memcpy)
|
|
|
|
libc_hidden_builtin_def (memcpy)
|