1 /* Optimized strcpy 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] strcpy (char *dest [r3], const char *src [r4]) */
29 #define rRTN r3 /* incoming DEST arg preserved as result */
30 #define rSRC r4 /* pointer to previous word in src */
31 #define rDEST r5 /* pointer to previous word in dest */
32 #define rWORD r6 /* current word from src */
33 #define rFEFE r7 /* constant 0xfefefefefefefeff (-0x0101010101010101) */
34 #define r7F7F r8 /* constant 0x7f7f7f7f7f7f7f7f */
35 #define rNEG r9 /* ~(word in s1 | 0x7f7f7f7f7f7f7f7f) */
36 #define rALT r10 /* alternate word from src */
40 clrldi. rTMP, rTMP, 61
48 addi rFEFE, rFEFE, -0x101
49 addi r7F7F, r7F7F, 0x7f7f
51 insrdi r7F7F, r7F7F, 32, 0
52 add rFEFE, rFEFE, rTMP
55 L(g0): ldu rALT, 8(rSRC)
63 L(g2): add rTMP, rFEFE, rWORD
64 nor rNEG, r7F7F, rWORD
69 /* We've hit the end of the string. Do the rest byte-by-byte. */
71 extrdi. rTMP, rALT, 8, 0
74 extrdi. rTMP, rALT, 8, 8
77 extrdi. rTMP, rALT, 8, 16
80 extrdi. rTMP, rALT, 8, 24
83 extrdi. rTMP, rALT, 8, 32
86 extrdi. rTMP, rALT, 8, 40
89 extrdi. rTMP, rALT, 8, 48
95 /* Oh well. In this case, we just do a byte-by-byte copy. */
104 L(u0): lbzu rALT, 1(rSRC)
108 nop /* Let 601 load start of loop. */
113 L(u2): stb rWORD, 1(rDEST)
115 L(u1): stb rALT, 1(rDEST)
119 libc_hidden_builtin_def (strcpy)