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/* Optimized memcpy implementation for PowerPC A2.
Copyright (C) 2010-2023 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>
#ifndef MEMCPY
# define MEMCPY memcpy
#endif
#define PREFETCH_AHEAD 4 /* no cache lines SRC prefetching ahead */
#define ZERO_AHEAD 2 /* no cache lines DST zeroing ahead */
.section ".toc","aw"
__GLRO_DEF(dl_cache_line_size)
.section ".text"
.align 2
.machine a2
ENTRY (MEMCPY, 5)
CALL_MCOUNT 3
dcbt 0,r4 /* Prefetch ONE SRC cacheline */
cmpldi cr1,r5,16 /* is size < 16 ? */
mr r6,r3 /* Copy dest reg to r6; */
blt+ cr1,L(shortcopy)
/* Big copy (16 bytes or more)
Figure out how far to the nearest quadword boundary, or if we are
on one already. Also get the cache line size.
r3 - return value (always)
r4 - current source addr
r5 - copy length
r6 - current dest addr
*/
neg r8,r3 /* LS 4 bits = # bytes to 8-byte dest bdry */
/* Get the cache line size. */
__GLRO (r9, dl_cache_line_size,
RTLD_GLOBAL_RO_DL_CACHE_LINE_SIZE_OFFSET)
clrldi r8,r8,64-4 /* align to 16byte boundary */
sub r7,r4,r3 /* compute offset to src from dest */
cmpldi cr0,r8,0 /* Were we aligned on a 16 byte bdy? */
addi r10,r9,-1 /* Cache line mask */
beq+ L(dst_aligned)
/* Destination is not aligned on quadword boundary. Get us to one.
r3 - return value (always)
r4 - current source addr
r5 - copy length
r6 - current dest addr
r7 - offset to src from dest
r8 - number of bytes to quadword boundary
*/
mtcrf 0x01,r8 /* put #bytes to boundary into cr7 */
subf r5,r8,r5 /* adjust remaining len */
bf cr7*4+3,1f
lbzx r0,r7,r6 /* copy 1 byte addr */
stb r0,0(r6)
addi r6,r6,1
1:
bf cr7*4+2,2f
lhzx r0,r7,r6 /* copy 2 byte addr */
sth r0,0(r6)
addi r6,r6,2
2:
bf cr7*4+1,4f
lwzx r0,r7,r6 /* copy 4 byte addr */
stw r0,0(r6)
addi r6,r6,4
4:
bf cr7*4+0,8f
ldx r0,r7,r6 /* copy 8 byte addr */
std r0,0(r6)
addi r6,r6,8
8:
add r4,r7,r6 /* update src addr */
/* Dest is quadword aligned now.
Lots of decisions to make. If we are copying less than a cache
line we won't be here long. If we are not on a cache line
boundary we need to get there. And then we need to figure out
how many cache lines ahead to pre-touch.
r3 - return value (always)
r4 - current source addr
r5 - copy length
r6 - current dest addr
*/
.align 4
L(dst_aligned):
cmpdi cr0,r9,0 /* Cache line size set? */
bne+ cr0,L(cachelineset)
/* Cache line size not set: generic byte copy without much optimization */
clrldi. r0,r5,63 /* If length is odd copy one byte */
beq L(cachelinenotset_align)
lbz r7,0(r4) /* Read one byte from source */
addi r5,r5,-1 /* Update length */
addi r4,r4,1 /* Update source pointer address */
stb r7,0(r6) /* Store one byte at dest */
addi r6,r6,1 /* Update dest pointer address */
L(cachelinenotset_align):
cmpdi cr7,r5,0 /* If length is 0 return */
beqlr cr7
ori r2,r2,0 /* Force a new dispatch group */
L(cachelinenotset_loop):
addic. r5,r5,-2 /* Update length */
lbz r7,0(r4) /* Load 2 bytes from source */
lbz r8,1(r4)
addi r4,r4,2 /* Update source pointer address */
stb r7,0(r6) /* Store 2 bytes on dest */
stb r8,1(r6)
addi r6,r6,2 /* Update dest pointer address */
bne L(cachelinenotset_loop)
blr
L(cachelineset):
cmpd cr5,r5,r10 /* Less than a cacheline to go? */
neg r7,r6 /* How far to next cacheline bdy? */
addi r6,r6,-8 /* prepare for stdu */
cmpdi cr0,r9,128
addi r4,r4,-8 /* prepare for ldu */
ble+ cr5,L(lessthancacheline)
beq- cr0,L(big_lines) /* 128 byte line code */
/* More than a cacheline left to go, and using 64 byte cachelines */
clrldi r7,r7,64-6 /* How far to next cacheline bdy? */
cmpldi cr6,r7,0 /* Are we on a cacheline bdy already? */
/* Reduce total len by what it takes to get to the next cache line */
subf r5,r7,r5
srdi r7,r7,4 /* How many qws to get to the line bdy? */
/* How many full cache lines to copy after getting to a line bdy? */
srdi r10,r5,6
cmpldi r10,0 /* If no full cache lines to copy ... */
li r11,0 /* number cachelines to copy with prefetch */
beq L(nocacheprefetch)
/* We are here because we have at least one full cache line to copy,
and therefore some pre-touching to do. */
cmpldi r10,PREFETCH_AHEAD
li r12,64+8 /* prefetch distance */
ble L(lessthanmaxprefetch)
/* We can only do so much pre-fetching. R11 will have the count of
lines left to prefetch after the initial batch of prefetches
are executed. */
subi r11,r10,PREFETCH_AHEAD
li r10,PREFETCH_AHEAD
L(lessthanmaxprefetch):
mtctr r10
/* At this point r10/ctr hold the number of lines to prefetch in this
initial batch, and r11 holds any remainder. */
L(prefetchSRC):
dcbt r12,r4
addi r12,r12,64
bdnz L(prefetchSRC)
/* Prefetching is done, or was not needed.
cr6 - are we on a cacheline boundary already?
r7 - number of quadwords to the next cacheline boundary
*/
L(nocacheprefetch):
mtctr r7
cmpldi cr1,r5,64 /* Less than a cache line to copy? */
/* How many bytes are left after we copy whatever full
cache lines we can get? */
clrldi r5,r5,64-6
beq cr6,L(cachelinealigned)
/* Copy quadwords up to the next cacheline boundary */
L(aligntocacheline):
ld r9,0x08(r4)
ld r7,0x10(r4)
addi r4,r4,0x10
std r9,0x08(r6)
stdu r7,0x10(r6)
bdnz L(aligntocacheline)
.align 4
L(cachelinealigned): /* copy while cache lines */
blt- cr1,L(lessthancacheline) /* size <64 */
L(outerloop):
cmpdi r11,0
mtctr r11
beq- L(endloop)
li r11,64*ZERO_AHEAD +8 /* DCBZ dist */
.align 4
/* Copy whole cachelines, optimized by prefetching SRC cacheline */
L(loop): /* Copy aligned body */
dcbt r12,r4 /* PREFETCH SOURCE some cache lines ahead */
ld r9, 0x08(r4)
dcbz r11,r6
ld r7, 0x10(r4)
ld r8, 0x18(r4)
ld r0, 0x20(r4)
std r9, 0x08(r6)
std r7, 0x10(r6)
std r8, 0x18(r6)
std r0, 0x20(r6)
ld r9, 0x28(r4)
ld r7, 0x30(r4)
ld r8, 0x38(r4)
ld r0, 0x40(r4)
addi r4, r4,0x40
std r9, 0x28(r6)
std r7, 0x30(r6)
std r8, 0x38(r6)
stdu r0, 0x40(r6)
bdnz L(loop)
L(endloop):
cmpdi r10,0
beq- L(endloop2)
mtctr r10
L(loop2): /* Copy aligned body */
ld r9, 0x08(r4)
ld r7, 0x10(r4)
ld r8, 0x18(r4)
ld r0, 0x20(r4)
std r9, 0x08(r6)
std r7, 0x10(r6)
std r8, 0x18(r6)
std r0, 0x20(r6)
ld r9, 0x28(r4)
ld r7, 0x30(r4)
ld r8, 0x38(r4)
ld r0, 0x40(r4)
addi r4, r4,0x40
std r9, 0x28(r6)
std r7, 0x30(r6)
std r8, 0x38(r6)
stdu r0, 0x40(r6)
bdnz L(loop2)
L(endloop2):
.align 4
L(lessthancacheline): /* Was there less than cache to do ? */
cmpldi cr0,r5,16
srdi r7,r5,4 /* divide size by 16 */
blt- L(do_lt16)
mtctr r7
L(copy_remaining):
ld r8,0x08(r4)
ld r7,0x10(r4)
addi r4,r4,0x10
std r8,0x08(r6)
stdu r7,0x10(r6)
bdnz L(copy_remaining)
L(do_lt16): /* less than 16 ? */
cmpldi cr0,r5,0 /* copy remaining bytes (0-15) */
beqlr+ /* no rest to copy */
addi r4,r4,8
addi r6,r6,8
L(shortcopy): /* SIMPLE COPY to handle size =< 15 bytes */
mtcrf 0x01,r5
sub r7,r4,r6
bf- cr7*4+0,8f
ldx r0,r7,r6 /* copy 8 byte */
std r0,0(r6)
addi r6,r6,8
8:
bf cr7*4+1,4f
lwzx r0,r7,r6 /* copy 4 byte */
stw r0,0(r6)
addi r6,r6,4
4:
bf cr7*4+2,2f
lhzx r0,r7,r6 /* copy 2 byte */
sth r0,0(r6)
addi r6,r6,2
2:
bf cr7*4+3,1f
lbzx r0,r7,r6 /* copy 1 byte */
stb r0,0(r6)
1:
blr
/* Similar to above, but for use with 128 byte lines. */
L(big_lines):
clrldi r7,r7,64-7 /* How far to next cacheline bdy? */
cmpldi cr6,r7,0 /* Are we on a cacheline bdy already? */
/* Reduce total len by what it takes to get to the next cache line */
subf r5,r7,r5
srdi r7,r7,4 /* How many qws to get to the line bdy? */
/* How many full cache lines to copy after getting to a line bdy? */
srdi r10,r5,7
cmpldi r10,0 /* If no full cache lines to copy ... */
li r11,0 /* number cachelines to copy with prefetch */
beq L(nocacheprefetch_128)
/* We are here because we have at least one full cache line to copy,
and therefore some pre-touching to do. */
cmpldi r10,PREFETCH_AHEAD
li r12,128+8 /* prefetch distance */
ble L(lessthanmaxprefetch_128)
/* We can only do so much pre-fetching. R11 will have the count of
lines left to prefetch after the initial batch of prefetches
are executed. */
subi r11,r10,PREFETCH_AHEAD
li r10,PREFETCH_AHEAD
L(lessthanmaxprefetch_128):
mtctr r10
/* At this point r10/ctr hold the number of lines to prefetch in this
initial batch, and r11 holds any remainder. */
L(prefetchSRC_128):
dcbt r12,r4
addi r12,r12,128
bdnz L(prefetchSRC_128)
/* Prefetching is done, or was not needed.
cr6 - are we on a cacheline boundary already?
r7 - number of quadwords to the next cacheline boundary
*/
L(nocacheprefetch_128):
mtctr r7
cmpldi cr1,r5,128 /* Less than a cache line to copy? */
/* How many bytes are left after we copy whatever full
cache lines we can get? */
clrldi r5,r5,64-7
beq cr6,L(cachelinealigned_128)
/* Copy quadwords up to the next cacheline boundary */
L(aligntocacheline_128):
ld r9,0x08(r4)
ld r7,0x10(r4)
addi r4,r4,0x10
std r9,0x08(r6)
stdu r7,0x10(r6)
bdnz L(aligntocacheline_128)
L(cachelinealigned_128): /* copy while cache lines */
blt- cr1,L(lessthancacheline) /* size <128 */
L(outerloop_128):
cmpdi r11,0
mtctr r11
beq- L(endloop_128)
li r11,128*ZERO_AHEAD +8 /* DCBZ dist */
.align 4
/* Copy whole cachelines, optimized by prefetching SRC cacheline */
L(loop_128): /* Copy aligned body */
dcbt r12,r4 /* PREFETCH SOURCE some cache lines ahead */
ld r9, 0x08(r4)
dcbz r11,r6
ld r7, 0x10(r4)
ld r8, 0x18(r4)
ld r0, 0x20(r4)
std r9, 0x08(r6)
std r7, 0x10(r6)
std r8, 0x18(r6)
std r0, 0x20(r6)
ld r9, 0x28(r4)
ld r7, 0x30(r4)
ld r8, 0x38(r4)
ld r0, 0x40(r4)
std r9, 0x28(r6)
std r7, 0x30(r6)
std r8, 0x38(r6)
std r0, 0x40(r6)
ld r9, 0x48(r4)
ld r7, 0x50(r4)
ld r8, 0x58(r4)
ld r0, 0x60(r4)
std r9, 0x48(r6)
std r7, 0x50(r6)
std r8, 0x58(r6)
std r0, 0x60(r6)
ld r9, 0x68(r4)
ld r7, 0x70(r4)
ld r8, 0x78(r4)
ld r0, 0x80(r4)
addi r4, r4,0x80
std r9, 0x68(r6)
std r7, 0x70(r6)
std r8, 0x78(r6)
stdu r0, 0x80(r6)
bdnz L(loop_128)
L(endloop_128):
cmpdi r10,0
beq- L(endloop2_128)
mtctr r10
L(loop2_128): /* Copy aligned body */
ld r9, 0x08(r4)
ld r7, 0x10(r4)
ld r8, 0x18(r4)
ld r0, 0x20(r4)
std r9, 0x08(r6)
std r7, 0x10(r6)
std r8, 0x18(r6)
std r0, 0x20(r6)
ld r9, 0x28(r4)
ld r7, 0x30(r4)
ld r8, 0x38(r4)
ld r0, 0x40(r4)
std r9, 0x28(r6)
std r7, 0x30(r6)
std r8, 0x38(r6)
std r0, 0x40(r6)
ld r9, 0x48(r4)
ld r7, 0x50(r4)
ld r8, 0x58(r4)
ld r0, 0x60(r4)
std r9, 0x48(r6)
std r7, 0x50(r6)
std r8, 0x58(r6)
std r0, 0x60(r6)
ld r9, 0x68(r4)
ld r7, 0x70(r4)
ld r8, 0x78(r4)
ld r0, 0x80(r4)
addi r4, r4,0x80
std r9, 0x68(r6)
std r7, 0x70(r6)
std r8, 0x78(r6)
stdu r0, 0x80(r6)
bdnz L(loop2_128)
L(endloop2_128):
b L(lessthancacheline)
END_GEN_TB (MEMCPY,TB_TOCLESS)
libc_hidden_builtin_def (memcpy)
|
