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/* Optimized memcpy implementation for PowerPC A2.
Copyright (C) 2010-2025 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>
#define PREFETCH_AHEAD 4 /* no cache lines SRC prefetching ahead */
#define ZERO_AHEAD 2 /* no cache lines DST zeroing ahead */
.machine a2
EALIGN (memcpy, 5, 0)
CALL_MCOUNT
dcbt 0,r4 /* Prefetch ONE SRC cacheline */
cmplwi 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.
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 */
clrlwi r8,r8,32-4 /* align to 16byte boundary */
sub r7,r4,r3 /* compute offset to src from dest */
cmplwi cr0,r8,0 /* Were we aligned on a 16 byte bdy? */
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
lfdx r0,r7,r6 /* copy 8 byte addr */
stfd 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):
#ifdef PIC
mflr r0
/* Establishes GOT addressability so we can load the cache line size
from rtld_global_ro. This value was set from the aux vector during
startup. */
SETUP_GOT_ACCESS(r9,got_label)
addis r9,r9,_GLOBAL_OFFSET_TABLE_-got_label@ha
addi r9,r9,_GLOBAL_OFFSET_TABLE_-got_label@l
mtlr r0
#endif
__GLRO(r9, r9, _dl_cache_line_size,
RTLD_GLOBAL_RO_DL_CACHE_LINE_SIZE_OFFSET)
cmplwi cr5, r9, 0
bne+ cr5,L(cachelineset)
/* Cache line size not set: generic byte copy without much optimization */
andi. r0,r5,1 /* 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 on dest. */
addi r6,r6,1 /* Update dest pointer address. */
L(cachelinenotset_align):
cmpwi 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):
addi r10,r9,-1
cmpw 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 */
cmpwi 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 */
clrlwi r7,r7,32-6 /* How far to next cacheline bdy? */
cmplwi 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
srwi 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? */
srwi r10,r5,6
cmplwi 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. */
cmplwi 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
cmplwi 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? */
clrlwi r5,r5,32-6
beq cr6,L(cachelinealigned)
/* Copy quadwords up to the next cacheline boundary */
L(aligntocacheline):
lfd fp9,0x08(r4)
lfdu fp10,0x10(r4)
stfd fp9,0x08(r6)
stfdu fp10,0x10(r6)
bdnz L(aligntocacheline)
.align 4
L(cachelinealigned): /* copy while cache lines */
blt- cr1,L(lessthancacheline) /* size <64 */
L(outerloop):
cmpwi 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 */
lfd fp9, 0x08(r4)
dcbz r11,r6
lfd fp10, 0x10(r4)
lfd fp11, 0x18(r4)
lfd fp12, 0x20(r4)
stfd fp9, 0x08(r6)
stfd fp10, 0x10(r6)
stfd fp11, 0x18(r6)
stfd fp12, 0x20(r6)
lfd fp9, 0x28(r4)
lfd fp10, 0x30(r4)
lfd fp11, 0x38(r4)
lfdu fp12, 0x40(r4)
stfd fp9, 0x28(r6)
stfd fp10, 0x30(r6)
stfd fp11, 0x38(r6)
stfdu fp12, 0x40(r6)
bdnz L(loop)
L(endloop):
cmpwi r10,0
beq- L(endloop2)
mtctr r10
L(loop2): /* Copy aligned body */
lfd fp9, 0x08(r4)
lfd fp10, 0x10(r4)
lfd fp11, 0x18(r4)
lfd fp12, 0x20(r4)
stfd fp9, 0x08(r6)
stfd fp10, 0x10(r6)
stfd fp11, 0x18(r6)
stfd fp12, 0x20(r6)
lfd fp9, 0x28(r4)
lfd fp10, 0x30(r4)
lfd fp11, 0x38(r4)
lfdu fp12, 0x40(r4)
stfd fp9, 0x28(r6)
stfd fp10, 0x30(r6)
stfd fp11, 0x38(r6)
stfdu fp12, 0x40(r6)
bdnz L(loop2)
L(endloop2):
.align 4
L(lessthancacheline): /* Was there less than cache to do ? */
cmplwi cr0,r5,16
srwi r7,r5,4 /* divide size by 16 */
blt- L(do_lt16)
mtctr r7
L(copy_remaining):
lfd fp9, 0x08(r4)
lfdu fp10, 0x10(r4)
stfd fp9, 0x08(r6)
stfdu fp10, 0x10(r6)
bdnz L(copy_remaining)
L(do_lt16): /* less than 16 ? */
cmplwi 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
lfdx fp9,r7,r6 /* copy 8 byte */
stfd fp9,0(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):
clrlwi r7,r7,32-7 /* How far to next cacheline bdy? */
cmplwi 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
srwi r7,r7,4 /* How many qw to get to the line bdy? */
/* How many full cache lines to copy after getting to a line bdy? */
srwi r10,r5,7
cmplwi 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. */
cmplwi 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
cmplwi 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? */
clrlwi r5,r5,32-7
beq cr6,L(cachelinealigned_128)
/* Copy quadwords up to the next cacheline boundary */
L(aligntocacheline_128):
lfd fp9,0x08(r4)
lfdu fp10,0x10(r4)
stfd fp9,0x08(r6)
stfdu fp10,0x10(r6)
bdnz L(aligntocacheline_128)
L(cachelinealigned_128): /* copy while cache lines */
blt- cr1,L(lessthancacheline) /* size <128 */
L(outerloop_128):
cmpwi 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 */
lfd fp9, 0x08(r4)
dcbz r11,r6
lfd fp10, 0x10(r4)
lfd fp11, 0x18(r4)
lfd fp12, 0x20(r4)
stfd fp9, 0x08(r6)
stfd fp10, 0x10(r6)
stfd fp11, 0x18(r6)
stfd fp12, 0x20(r6)
lfd fp9, 0x28(r4)
lfd fp10, 0x30(r4)
lfd fp11, 0x38(r4)
lfd fp12, 0x40(r4)
stfd fp9, 0x28(r6)
stfd fp10, 0x30(r6)
stfd fp11, 0x38(r6)
stfd fp12, 0x40(r6)
lfd fp9, 0x48(r4)
lfd fp10, 0x50(r4)
lfd fp11, 0x58(r4)
lfd fp12, 0x60(r4)
stfd fp9, 0x48(r6)
stfd fp10, 0x50(r6)
stfd fp11, 0x58(r6)
stfd fp12, 0x60(r6)
lfd fp9, 0x68(r4)
lfd fp10, 0x70(r4)
lfd fp11, 0x78(r4)
lfdu fp12, 0x80(r4)
stfd fp9, 0x68(r6)
stfd fp10, 0x70(r6)
stfd fp11, 0x78(r6)
stfdu fp12, 0x80(r6)
bdnz L(loop_128)
L(endloop_128):
cmpwi r10,0
beq- L(endloop2_128)
mtctr r10
L(loop2_128): /* Copy aligned body */
lfd fp9, 0x08(r4)
lfd fp10, 0x10(r4)
lfd fp11, 0x18(r4)
lfd fp12, 0x20(r4)
stfd fp9, 0x08(r6)
stfd fp10, 0x10(r6)
stfd fp11, 0x18(r6)
stfd fp12, 0x20(r6)
lfd fp9, 0x28(r4)
lfd fp10, 0x30(r4)
lfd fp11, 0x38(r4)
lfd fp12, 0x40(r4)
stfd fp9, 0x28(r6)
stfd fp10, 0x30(r6)
stfd fp11, 0x38(r6)
stfd fp12, 0x40(r6)
lfd fp9, 0x48(r4)
lfd fp10, 0x50(r4)
lfd fp11, 0x58(r4)
lfd fp12, 0x60(r4)
stfd fp9, 0x48(r6)
stfd fp10, 0x50(r6)
stfd fp11, 0x58(r6)
stfd fp12, 0x60(r6)
lfd fp9, 0x68(r4)
lfd fp10, 0x70(r4)
lfd fp11, 0x78(r4)
lfdu fp12, 0x80(r4)
stfd fp9, 0x68(r6)
stfd fp10, 0x70(r6)
stfd fp11, 0x78(r6)
stfdu fp12, 0x80(r6)
bdnz L(loop2_128)
L(endloop2_128):
b L(lessthancacheline)
END (memcpy)
libc_hidden_builtin_def (memcpy)
|
