summaryrefslogtreecommitdiffstats
path: root/arch/sh/lib/clear_page.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/sh/lib/clear_page.S')
-rw-r--r--arch/sh/lib/clear_page.S154
1 files changed, 154 insertions, 0 deletions
diff --git a/arch/sh/lib/clear_page.S b/arch/sh/lib/clear_page.S
new file mode 100644
index 000000000000..3539123fe517
--- /dev/null
+++ b/arch/sh/lib/clear_page.S
@@ -0,0 +1,154 @@
+/*
+ * __clear_user_page, __clear_user, clear_page implementation of SuperH
+ *
+ * Copyright (C) 2001 Kaz Kojima
+ * Copyright (C) 2001, 2002 Niibe Yutaka
+ * Copyright (C) 2006 Paul Mundt
+ */
+#include <linux/linkage.h>
+#include <asm/page.h>
+
+/*
+ * clear_page
+ * @to: P1 address
+ *
+ * void clear_page(void *to)
+ */
+
+/*
+ * r0 --- scratch
+ * r4 --- to
+ * r5 --- to + PAGE_SIZE
+ */
+ENTRY(clear_page)
+ mov r4,r5
+ mov.l .Llimit,r0
+ add r0,r5
+ mov #0,r0
+ !
+1:
+#if defined(CONFIG_CPU_SH3)
+ mov.l r0,@r4
+#elif defined(CONFIG_CPU_SH4)
+ movca.l r0,@r4
+ mov r4,r1
+#endif
+ add #32,r4
+ mov.l r0,@-r4
+ mov.l r0,@-r4
+ mov.l r0,@-r4
+ mov.l r0,@-r4
+ mov.l r0,@-r4
+ mov.l r0,@-r4
+ mov.l r0,@-r4
+#if defined(CONFIG_CPU_SH4)
+ ocbwb @r1
+#endif
+ cmp/eq r5,r4
+ bf/s 1b
+ add #28,r4
+ !
+ rts
+ nop
+
+ .balign 4
+.Llimit: .long (PAGE_SIZE-28)
+
+ENTRY(__clear_user)
+ !
+ mov #0, r0
+ mov #0xe0, r1 ! 0xffffffe0
+ !
+ ! r4..(r4+31)&~32 -------- not aligned [ Area 0 ]
+ ! (r4+31)&~32..(r4+r5)&~32 -------- aligned [ Area 1 ]
+ ! (r4+r5)&~32..r4+r5 -------- not aligned [ Area 2 ]
+ !
+ ! Clear area 0
+ mov r4, r2
+ !
+ tst r1, r5 ! length < 32
+ bt .Larea2 ! skip to remainder
+ !
+ add #31, r2
+ and r1, r2
+ cmp/eq r4, r2
+ bt .Larea1
+ mov r2, r3
+ sub r4, r3
+ mov r3, r7
+ mov r4, r2
+ !
+.L0: dt r3
+0: mov.b r0, @r2
+ bf/s .L0
+ add #1, r2
+ !
+ sub r7, r5
+ mov r2, r4
+.Larea1:
+ mov r4, r3
+ add r5, r3
+ and r1, r3
+ cmp/hi r2, r3
+ bf .Larea2
+ !
+ ! Clear area 1
+#if defined(CONFIG_CPU_SH4)
+1: movca.l r0, @r2
+#else
+1: mov.l r0, @r2
+#endif
+ add #4, r2
+2: mov.l r0, @r2
+ add #4, r2
+3: mov.l r0, @r2
+ add #4, r2
+4: mov.l r0, @r2
+ add #4, r2
+5: mov.l r0, @r2
+ add #4, r2
+6: mov.l r0, @r2
+ add #4, r2
+7: mov.l r0, @r2
+ add #4, r2
+8: mov.l r0, @r2
+ add #4, r2
+ cmp/hi r2, r3
+ bt/s 1b
+ nop
+ !
+ ! Clear area 2
+.Larea2:
+ mov r4, r3
+ add r5, r3
+ cmp/hs r3, r2
+ bt/s .Ldone
+ sub r2, r3
+.L2: dt r3
+9: mov.b r0, @r2
+ bf/s .L2
+ add #1, r2
+ !
+.Ldone: rts
+ mov #0, r0 ! return 0 as normal return
+
+ ! return the number of bytes remained
+.Lbad_clear_user:
+ mov r4, r0
+ add r5, r0
+ rts
+ sub r2, r0
+
+.section __ex_table,"a"
+ .align 2
+ .long 0b, .Lbad_clear_user
+ .long 1b, .Lbad_clear_user
+ .long 2b, .Lbad_clear_user
+ .long 3b, .Lbad_clear_user
+ .long 4b, .Lbad_clear_user
+ .long 5b, .Lbad_clear_user
+ .long 6b, .Lbad_clear_user
+ .long 7b, .Lbad_clear_user
+ .long 8b, .Lbad_clear_user
+ .long 9b, .Lbad_clear_user
+.previous