1 /* Optimized stpcpy implementation for PowerPC64.
2 Copyright (C) 1997-2013 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
21 /* See strlen.s for comments on how the end-of-string testing works. */
23 /* char * [r3] stpcpy (char *dest [r3], const char *src [r4]) */
25 EALIGN (__stpcpy, 4, 0)
30 #define rDEST r3 /* pointer to previous word in dest */
31 #define rSRC r4 /* pointer to previous word in src */
32 #define rWORD r6 /* current word from src */
33 #define rFEFE r7 /* 0xfefefeff */
34 #define r7F7F r8 /* 0x7f7f7f7f */
35 #define rNEG r9 /* ~(word in src | 0x7f7f7f7f) */
36 #define rALT r10 /* alternate word from src */
39 clrldi. rTMP, rTMP, 62
46 addi rFEFE, rFEFE, -0x101
47 addi r7F7F, r7F7F, 0x7f7f
50 L(g0): lwzu rALT, 4(rSRC)
58 L(g2): add rTMP, rFEFE, rWORD
59 nor rNEG, r7F7F, rWORD
64 /* We've hit the end of the string. Do the rest byte-by-byte. */
65 L(g1): rlwinm. rTMP, rALT, 8, 24, 31
68 rlwinm. rTMP, rALT, 16, 24, 31
71 rlwinm. rTMP, rALT, 24, 24, 31
77 /* Oh well. In this case, we just do a byte-by-byte copy. */
86 L(u0): lbzu rALT, 1(rSRC)
90 nop /* Let 601 load start of loop. */
95 L(u2): stbu rWORD, 1(rDEST)
97 L(u1): stbu rALT, 1(rDEST)
101 weak_alias (__stpcpy, stpcpy)
102 libc_hidden_def (__stpcpy)
103 libc_hidden_builtin_def (stpcpy)