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/* Optimized strcpy implementation for PowerPC.
Copyright (C) 1997, 1999, 2000 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#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)
#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 0xfefefeff (-0x01010101) */
#define r7F7F r8 /* constant 0x7f7f7f7f */
#define rNEG r9 /* ~(word in s1 | 0x7f7f7f7f) */
#define rALT r10 /* alternate word from src */
or rTMP, rSRC, rRTN
clrlwi. rTMP, rTMP, 30
addi rDEST, rRTN, -4
bne L(unaligned)
lis rFEFE, -0x101
lis r7F7F, 0x7f7f
lwz rWORD, 0(rSRC)
addi rFEFE, rFEFE, -0x101
addi r7F7F, r7F7F, 0x7f7f
b L(g2)
L(g0): lwzu rALT, 4(rSRC)
stwu rWORD, 4(rDEST)
add rTMP, rFEFE, rALT
nor rNEG, r7F7F, rALT
and. rTMP, rTMP, rNEG
bne- L(g1)
lwzu rWORD, 4(rSRC)
stwu rALT, 4(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): rlwinm. rTMP, rALT, 8, 24, 31
stb rTMP, 4(rDEST)
beqlr-
rlwinm. rTMP, rALT, 16, 24, 31
stb rTMP, 5(rDEST)
beqlr-
rlwinm. rTMP, rALT, 24, 24, 31
stb rTMP, 6(rDEST)
beqlr-
stb rALT, 7(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)
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