mirror of
https://github.com/torvalds/linux.git
synced 2024-11-19 10:31:48 +00:00
55 lines
1.2 KiB
ArmAsm
55 lines
1.2 KiB
ArmAsm
/*
|
|
Copyright 2003 Richard Curnow, SuperH (UK) Ltd.
|
|
|
|
This file is subject to the terms and conditions of the GNU General Public
|
|
License. See the file "COPYING" in the main directory of this archive
|
|
for more details.
|
|
|
|
Tight version of memset for the case of just clearing a page. It turns out
|
|
that having the alloco's spaced out slightly due to the increment/branch
|
|
pair causes them to contend less for access to the cache. Similarly,
|
|
keeping the stores apart from the allocos causes less contention. => Do two
|
|
separate loops. Do multiple stores per loop to amortise the
|
|
increment/branch cost a little.
|
|
|
|
Parameters:
|
|
r2 : source effective address (start of page)
|
|
|
|
Always clears 4096 bytes.
|
|
|
|
Note : alloco guarded by synco to avoid TAKum03020 erratum
|
|
|
|
*/
|
|
|
|
.section .text..SHmedia32,"ax"
|
|
.little
|
|
|
|
.balign 8
|
|
.global clear_page
|
|
clear_page:
|
|
pta/l 1f, tr1
|
|
pta/l 2f, tr2
|
|
ptabs/l r18, tr0
|
|
|
|
movi 4096, r7
|
|
add r2, r7, r7
|
|
add r2, r63, r6
|
|
1:
|
|
alloco r6, 0
|
|
synco ! TAKum03020
|
|
addi r6, 32, r6
|
|
bgt/l r7, r6, tr1
|
|
|
|
add r2, r63, r6
|
|
2:
|
|
st.q r6, 0, r63
|
|
st.q r6, 8, r63
|
|
st.q r6, 16, r63
|
|
st.q r6, 24, r63
|
|
addi r6, 32, r6
|
|
bgt/l r7, r6, tr2
|
|
|
|
blink tr0, r63
|
|
|
|
|