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Diffstat (limited to 'arch/sh64/lib/page_clear.S')
-rw-r--r-- | arch/sh64/lib/page_clear.S | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/sh64/lib/page_clear.S b/arch/sh64/lib/page_clear.S new file mode 100644 index 000000000000..ac0111d669a3 --- /dev/null +++ b/arch/sh64/lib/page_clear.S | |||
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1 | /* | ||
2 | Copyright 2003 Richard Curnow, SuperH (UK) Ltd. | ||
3 | |||
4 | This file is subject to the terms and conditions of the GNU General Public | ||
5 | License. See the file "COPYING" in the main directory of this archive | ||
6 | for more details. | ||
7 | |||
8 | Tight version of memset for the case of just clearing a page. It turns out | ||
9 | that having the alloco's spaced out slightly due to the increment/branch | ||
10 | pair causes them to contend less for access to the cache. Similarly, | ||
11 | keeping the stores apart from the allocos causes less contention. => Do two | ||
12 | separate loops. Do multiple stores per loop to amortise the | ||
13 | increment/branch cost a little. | ||
14 | |||
15 | Parameters: | ||
16 | r2 : source effective address (start of page) | ||
17 | |||
18 | Always clears 4096 bytes. | ||
19 | |||
20 | Note : alloco guarded by synco to avoid TAKum03020 erratum | ||
21 | |||
22 | */ | ||
23 | |||
24 | .section .text..SHmedia32,"ax" | ||
25 | .little | ||
26 | |||
27 | .balign 8 | ||
28 | .global sh64_page_clear | ||
29 | sh64_page_clear: | ||
30 | pta/l 1f, tr1 | ||
31 | pta/l 2f, tr2 | ||
32 | ptabs/l r18, tr0 | ||
33 | |||
34 | movi 4096, r7 | ||
35 | add r2, r7, r7 | ||
36 | add r2, r63, r6 | ||
37 | 1: | ||
38 | alloco r6, 0 | ||
39 | synco ! TAKum03020 | ||
40 | addi r6, 32, r6 | ||
41 | bgt/l r7, r6, tr1 | ||
42 | |||
43 | add r2, r63, r6 | ||
44 | 2: | ||
45 | st.q r6, 0, r63 | ||
46 | st.q r6, 8, r63 | ||
47 | st.q r6, 16, r63 | ||
48 | st.q r6, 24, r63 | ||
49 | addi r6, 32, r6 | ||
50 | bgt/l r7, r6, tr2 | ||
51 | |||
52 | blink tr0, r63 | ||
53 | |||
54 | |||