1 /* Optimized memset implementation for PowerPC64.
2 Copyright (C) 1997,99, 2000,02,03, 2006 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, write to the Free
17 Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA
24 /* __ptr_t [r3] memset (__ptr_t s [r3], int c [r4], size_t n [r5]));
27 The memset is done in three sizes: byte (8 bits), word (32 bits),
28 cache line (1024 bits). There is a special case for setting cache lines
29 to 0, to take advantage of the dcbz instruction. */
31 EALIGN (BP_SYM (memset), 5, 0)
35 #define rRTN r3 /* Initial value of 1st argument. */
36 #define rMEMP0 r3 /* Original value of 1st arg. */
37 #define rCHR r4 /* Char to set in each byte. */
38 #define rLEN r5 /* Length of region to set. */
39 #define rMEMP r6 /* Address at which we are storing. */
40 #define rALIGN r7 /* Number of bytes we are setting now (when aligning). */
43 #define rNEG64 r8 /* Constant -64 for clearing with dcbz. */
44 #define rCLS r8 /* Cache line size (known to be 128). */
45 #define rCLM r9 /* Cache line size mask to check for cache alignment. */
47 /* Take care of case for size <= 4. */
49 andi. rALIGN, rMEMP0, 3
53 /* Align to word boundary. */
55 rlwimi rCHR, rCHR, 8, 16, 23 /* Replicate byte to halfword. */
58 subfic rALIGN, rALIGN, 4
59 add rMEMP, rMEMP, rALIGN
60 sub rLEN, rLEN, rALIGN
67 /* Handle the case of size < 31. */
70 rlwimi rCHR, rCHR, 16, 0, 15 /* Replicate halfword to word. */
72 /* Align to 32-byte boundary. */
73 andi. rALIGN, rMEMP, 0x1C
74 subfic rALIGN, rALIGN, 0x20
77 add rMEMP, rMEMP, rALIGN
78 sub rLEN, rLEN, rALIGN
79 cmplwi cr1, rALIGN, 0x10
88 stwu rCHR, -16(rMEMP2)
89 L(a2): bf 29, L(caligned)
92 /* Now aligned to a 32 byte boundary. */
95 clrrwi. rALIGN, rLEN, 5
97 beq cr1, L(zloopstart) /* Special case for clearing memory using dcbz. */
101 beq L(medium) /* We may not actually get to do a full line. */
102 clrlwi. rLEN, rLEN, 27
103 add rMEMP, rMEMP, rALIGN
108 L(c3): dcbtst rNEG64, rMEMP
116 stwu rCHR, -32(rMEMP)
127 stwu rCHR, -32(rMEMP)
129 add rMEMP, rMEMP, rALIGN
133 /* Clear lines of memory in 128-byte chunks. */
135 /* If the remaining length is less the 32 bytes, don't bother getting
136 the cache line size. */
138 li rCLS,128 /* cache line size is 128 */
143 blt cr1,L(handletail32)
157 /* Now we are aligned to the cache line and can use dcbz. */
161 blt cr1,L(handletail32)
167 /* We are here because the cache line size was set and the remainder
168 (rLEN) is less than the actual cache line size.
169 So set up the preconditions for L(nondcbz) and go there. */
171 clrrwi. rALIGN, rLEN, 5
176 /* Memset of 4 bytes or less. */
189 /* Memset of 0-31 bytes. */
194 add rMEMP, rMEMP, rLEN
196 bt- 31, L(medium_31t)
197 bt- 30, L(medium_30t)
199 bt- 29, L(medium_29t)
201 bge- cr1, L(medium_27t)
209 bf- 30, L(medium_30f)
212 bf- 29, L(medium_29f)
215 blt- cr1, L(medium_27f)
220 stwu rCHR, -16(rMEMP)
227 END (BP_SYM (memset))
228 libc_hidden_builtin_def (memset)