sh: Optimised memset for SH4
Optimised version of memset for the SH4 which uses movca.l.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/lib/Makefile b/arch/sh/lib/Makefile
index a969b47..dab4d21 100644
--- a/arch/sh/lib/Makefile
+++ b/arch/sh/lib/Makefile
@@ -2,7 +2,7 @@
# Makefile for SuperH-specific library files..
#
-lib-y = delay.o memset.o memmove.o memchr.o \
+lib-y = delay.o memmove.o memchr.o \
checksum.o strlen.o div64.o div64-generic.o
# Extracted from libgcc
@@ -23,8 +23,11 @@
memcpy-y := memcpy.o
memcpy-$(CONFIG_CPU_SH4) := memcpy-sh4.o
+memset-y := memset.o
+memset-$(CONFIG_CPU_SH4) := memset-sh4.o
+
lib-$(CONFIG_MMU) += copy_page.o __clear_user.o
lib-$(CONFIG_MCOUNT) += mcount.o
-lib-y += $(memcpy-y) $(udivsi3-y)
+lib-y += $(memcpy-y) $(memset-y) $(udivsi3-y)
EXTRA_CFLAGS += -Werror
diff --git a/arch/sh/lib/memset-sh4.S b/arch/sh/lib/memset-sh4.S
new file mode 100644
index 0000000..1a6e32c
--- /dev/null
+++ b/arch/sh/lib/memset-sh4.S
@@ -0,0 +1,107 @@
+/*
+ * "memset" implementation for SH4
+ *
+ * Copyright (C) 1999 Niibe Yutaka
+ * Copyright (c) 2009 STMicroelectronics Limited
+ * Author: Stuart Menefy <stuart.menefy:st.com>
+ */
+
+/*
+ * void *memset(void *s, int c, size_t n);
+ */
+
+#include <linux/linkage.h>
+
+ENTRY(memset)
+ mov #12,r0
+ add r6,r4
+ cmp/gt r6,r0
+ bt/s 40f ! if it's too small, set a byte at once
+ mov r4,r0
+ and #3,r0
+ cmp/eq #0,r0
+ bt/s 2f ! It's aligned
+ sub r0,r6
+1:
+ dt r0
+ bf/s 1b
+ mov.b r5,@-r4
+2: ! make VVVV
+ extu.b r5,r5
+ swap.b r5,r0 ! V0
+ or r0,r5 ! VV
+ swap.w r5,r0 ! VV00
+ or r0,r5 ! VVVV
+
+ ! Check if enough bytes need to be copied to be worth the big loop
+ mov #0x40, r0 ! (MT)
+ cmp/gt r6,r0 ! (MT) 64 > len => slow loop
+
+ bt/s 22f
+ mov r6,r0
+
+ ! align the dst to the cache block size if necessary
+ mov r4, r3
+ mov #~(0x1f), r1
+
+ and r3, r1
+ cmp/eq r3, r1
+
+ bt/s 11f ! dst is already aligned
+ sub r1, r3 ! r3-r1 -> r3
+ shlr2 r3 ! number of loops
+
+10: mov.l r5,@-r4
+ dt r3
+ bf/s 10b
+ add #-4, r6
+
+11: ! dst is 32byte aligned
+ mov r6,r2
+ mov #-5,r0
+ shld r0,r2 ! number of loops
+
+ add #-32, r4
+ mov r5, r0
+12:
+ movca.l r0,@r4
+ mov.l r5,@(4, r4)
+ mov.l r5,@(8, r4)
+ mov.l r5,@(12,r4)
+ mov.l r5,@(16,r4)
+ mov.l r5,@(20,r4)
+ add #-0x20, r6
+ mov.l r5,@(24,r4)
+ dt r2
+ mov.l r5,@(28,r4)
+ bf/s 12b
+ add #-32, r4
+
+ add #32, r4
+ mov #8, r0
+ cmp/ge r0, r6
+ bf 40f
+
+ mov r6,r0
+22:
+ shlr2 r0
+ shlr r0 ! r0 = r6 >> 3
+3:
+ dt r0
+ mov.l r5,@-r4 ! set 8-byte at once
+ bf/s 3b
+ mov.l r5,@-r4
+ !
+ mov #7,r0
+ and r0,r6
+
+ ! fill bytes (length may be zero)
+40: tst r6,r6
+ bt 5f
+4:
+ dt r6
+ bf/s 4b
+ mov.b r5,@-r4
+5:
+ rts
+ mov r4,r0