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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/sh64/lib/page_clear.S
Linux-2.6.12-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 00000000000..ac0111d669a
--- /dev/null
+++ b/arch/sh64/lib/page_clear.S
@@ -0,0 +1,54 @@
+/*
+ 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 sh64_page_clear
+sh64_page_clear:
+ 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
+
+