[Xen-devel] [PATCH 08/17] xen: arm32: add optimised strchr and strrchr routines

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

Taken from Linux v3.14-rc7.

These aren't widely used enough to be critical, but we may as well have them.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 xen/arch/arm/arm32/lib/Makefile  |    1 +
 xen/arch/arm/arm32/lib/strchr.S  |   29 +++++++++++++++++++++++++++++
 xen/arch/arm/arm32/lib/strrchr.S |   28 ++++++++++++++++++++++++++++
 xen/include/asm-arm/string.h     |   12 ++++++++++++
 4 files changed, 70 insertions(+)
 create mode 100644 xen/arch/arm/arm32/lib/strchr.S
 create mode 100644 xen/arch/arm/arm32/lib/strrchr.S

diff --git a/xen/arch/arm/arm32/lib/Makefile b/xen/arch/arm/arm32/lib/Makefile
index fa4e241..e9fbc59 100644
--- a/xen/arch/arm/arm32/lib/Makefile
+++ b/xen/arch/arm/arm32/lib/Makefile
@@ -2,4 +2,5 @@ obj-y += memcpy.o memmove.o memset.o memchr.o memzero.o
 obj-y += findbit.o setbit.o
 obj-y += setbit.o clearbit.o changebit.o
 obj-y += testsetbit.o testclearbit.o testchangebit.o
+obj-y += strchr.o strrchr.o
 obj-y += lib1funcs.o lshrdi3.o div64.o
diff --git a/xen/arch/arm/arm32/lib/strchr.S b/xen/arch/arm/arm32/lib/strchr.S
new file mode 100644
index 0000000..f01740e
--- /dev/null
+++ b/xen/arch/arm/arm32/lib/strchr.S
@@ -0,0 +1,29 @@
+/*
+ *  linux/arch/arm/lib/strchr.S
+ *
+ *  Copyright (C) 1995-2000 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *  ASM optimised string functions
+ */
+
+#include <xen/config.h>
+       
+#include "assembler.h"
+
+               .text
+               .align  5
+ENTRY(strchr)
+               and     r1, r1, #0xff
+1:             ldrb    r2, [r0], #1
+               teq     r2, r1
+               teqne   r2, #0
+               bne     1b
+               teq     r2, r1
+               movne   r0, #0
+               subeq   r0, r0, #1
+               mov     pc, lr
+ENDPROC(strchr)
diff --git a/xen/arch/arm/arm32/lib/strrchr.S b/xen/arch/arm/arm32/lib/strrchr.S
new file mode 100644
index 0000000..88fc0de
--- /dev/null
+++ b/xen/arch/arm/arm32/lib/strrchr.S
@@ -0,0 +1,28 @@
+/*
+ *  linux/arch/arm/lib/strrchr.S
+ *
+ *  Copyright (C) 1995-2000 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *  ASM optimised string functions
+ */
+
+#include <xen/config.h>
+       
+#include "assembler.h"
+
+               .text
+               .align  5
+ENTRY(strrchr)
+               mov     r3, #0
+1:             ldrb    r2, [r0], #1
+               teq     r2, r1
+               subeq   r3, r0, #1
+               teq     r2, #0
+               bne     1b
+               mov     r0, r3
+               mov     pc, lr
+ENDPROC(strrchr)
diff --git a/xen/include/asm-arm/string.h b/xen/include/asm-arm/string.h
index 2c9f4f7..7d8b35a 100644
--- a/xen/include/asm-arm/string.h
+++ b/xen/include/asm-arm/string.h
@@ -4,6 +4,18 @@
 #include <xen/config.h>
 
 #if defined(CONFIG_ARM_32)
+
+/*
+ * We don't do inline string functions, since the
+ * optimised inline asm versions are not small.
+ */
+
+#define __HAVE_ARCH_STRRCHR
+extern char * strrchr(const char * s, int c);
+
+#define __HAVE_ARCH_STRCHR
+extern char * strchr(const char * s, int c);
+
 #define __HAVE_ARCH_MEMCPY
 extern void * memcpy(void *, const void *, __kernel_size_t);
 
-- 
1.7.10.4


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