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/* Optimized strcpy implementation for PowerPC64.
Copyright (C) 1997-2013 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>
/* See strlen.s for comments on how the end-of-string testing works. */
/* char * [r3] strcpy (char *dest [r3], const char *src [r4]) */
EALIGN (strcpy, 4, 0)
CALL_MCOUNT 2
#define rTMP r0
#define rRTN r3 /* incoming DEST arg preserved as result */
#define rSRC r4 /* pointer to previous word in src */
#define rDEST r5 /* pointer to previous word in dest */
#define rWORD r6 /* current word from src */
#define rFEFE r7 /* constant 0xfefefefefefefeff (-0x0101010101010101) */
#define r7F7F r8 /* constant 0x7f7f7f7f7f7f7f7f */
#define rNEG r9 /* ~(word in s1 | 0x7f7f7f7f7f7f7f7f) */
#define rALT r10 /* alternate word from src */
dcbt 0,rSRC
or rTMP, rSRC, rRTN
clrldi. rTMP, rTMP, 61
addi rDEST, rRTN, -8
dcbtst 0,rRTN
bne L(unaligned)
lis rFEFE, -0x101
lis r7F7F, 0x7f7f
ld rWORD, 0(rSRC)
addi rFEFE, rFEFE, -0x101
addi r7F7F, r7F7F, 0x7f7f
sldi rTMP, rFEFE, 32
insrdi r7F7F, r7F7F, 32, 0
add rFEFE, rFEFE, rTMP
b L(g2)
L(g0): ldu rALT, 8(rSRC)
stdu rWORD, 8(rDEST)
add rTMP, rFEFE, rALT
nor rNEG, r7F7F, rALT
and. rTMP, rTMP, rNEG
bne- L(g1)
ldu rWORD, 8(rSRC)
stdu rALT, 8(rDEST)
L(g2): add rTMP, rFEFE, rWORD
nor rNEG, r7F7F, rWORD
and. rTMP, rTMP, rNEG
beq+ L(g0)
mr rALT, rWORD
/* We've hit the end of the string. Do the rest byte-by-byte. */
L(g1):
extrdi. rTMP, rALT, 8, 0
stb rTMP, 8(rDEST)
beqlr-
extrdi. rTMP, rALT, 8, 8
stb rTMP, 9(rDEST)
beqlr-
extrdi. rTMP, rALT, 8, 16
stb rTMP, 10(rDEST)
beqlr-
extrdi. rTMP, rALT, 8, 24
stb rTMP, 11(rDEST)
beqlr-
extrdi. rTMP, rALT, 8, 32
stb rTMP, 12(rDEST)
beqlr-
extrdi. rTMP, rALT, 8, 40
stb rTMP, 13(rDEST)
beqlr-
extrdi. rTMP, rALT, 8, 48
stb rTMP, 14(rDEST)
beqlr-
stb rALT, 15(rDEST)
blr
/* Oh well. In this case, we just do a byte-by-byte copy. */
.align 4
nop
L(unaligned):
lbz rWORD, 0(rSRC)
addi rDEST, rRTN, -1
cmpwi rWORD, 0
beq- L(u2)
L(u0): lbzu rALT, 1(rSRC)
stbu rWORD, 1(rDEST)
cmpwi rALT, 0
beq- L(u1)
nop /* Let 601 load start of loop. */
lbzu rWORD, 1(rSRC)
stbu rALT, 1(rDEST)
cmpwi rWORD, 0
bne+ L(u0)
L(u2): stb rWORD, 1(rDEST)
blr
L(u1): stb rALT, 1(rDEST)
blr
END (strcpy)
libc_hidden_builtin_def (strcpy)
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