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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/sh64/lib/page_clear.S
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/sh64/lib/page_clear.S')
-rw-r--r--arch/sh64/lib/page_clear.S54
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
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+++ b/arch/sh64/lib/page_clear.S
@@ -0,0 +1,54 @@
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
29sh64_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
371:
38 alloco r6, 0
39 synco ! TAKum03020
40 addi r6, 32, r6
41 bgt/l r7, r6, tr1
42
43 add r2, r63, r6
442:
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