blob: ac0111d669a32d52d55e1b0e214cf90060260acf [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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