From 56d205cc5c0a3032a605121d4253e111193bf923 Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem@davemloft.net>
Date: Tue, 2 Aug 2011 20:23:34 -0700
Subject: sparc: Use popc when possible for ffs/__ffs/ffz.

Signed-off-by: David S. Miller <davem@davemloft.net>
---
 arch/sparc/lib/Makefile |  2 +-
 arch/sparc/lib/ffs.S    | 84 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+), 1 deletion(-)
 create mode 100644 arch/sparc/lib/ffs.S

(limited to 'arch/sparc/lib')

diff --git a/arch/sparc/lib/Makefile b/arch/sparc/lib/Makefile
index 11c850a9b66f..a3fc4375a150 100644
--- a/arch/sparc/lib/Makefile
+++ b/arch/sparc/lib/Makefile
@@ -37,7 +37,7 @@ lib-$(CONFIG_SPARC64) += GENmemcpy.o GENcopy_from_user.o GENcopy_to_user.o
 lib-$(CONFIG_SPARC64) += GENpatch.o GENpage.o GENbzero.o
 
 lib-$(CONFIG_SPARC64) += copy_in_user.o user_fixup.o memmove.o
-lib-$(CONFIG_SPARC64) += mcount.o ipcsum.o xor.o hweight.o
+lib-$(CONFIG_SPARC64) += mcount.o ipcsum.o xor.o hweight.o ffs.o
 
 obj-y                 += iomap.o
 obj-$(CONFIG_SPARC32) += atomic32.o
diff --git a/arch/sparc/lib/ffs.S b/arch/sparc/lib/ffs.S
new file mode 100644
index 000000000000..b39389f69899
--- /dev/null
+++ b/arch/sparc/lib/ffs.S
@@ -0,0 +1,84 @@
+#include <linux/linkage.h>
+
+	.register	%g2,#scratch
+
+	.text
+	.align	32
+
+ENTRY(ffs)
+	brnz,pt	%o0, 1f
+	 mov	1, %o1
+	retl
+	 clr	%o0
+	nop
+	nop
+ENTRY(__ffs)
+	sllx	%o0, 32, %g1		/* 1  */
+	srlx	%o0, 32, %g2
+
+	clr	%o1			/* 2  */
+	movrz	%g1, %g2, %o0
+
+	movrz	%g1, 32, %o1		/* 3  */
+1:	clr	%o2
+
+	sllx	%o0, (64 - 16), %g1	/* 4  */
+	srlx	%o0, 16, %g2
+
+	movrz	%g1, %g2, %o0		/* 5  */
+	clr	%o3
+
+	movrz	%g1, 16, %o2		/* 6  */
+	clr	%o4
+
+	and	%o0, 0xff, %g1		/* 7  */
+	srlx	%o0, 8, %g2
+
+	movrz	%g1, %g2, %o0		/* 8  */
+	clr	%o5
+
+	movrz	%g1, 8, %o3		/* 9  */
+	add	%o2, %o1, %o2
+
+	and	%o0, 0xf, %g1		/* 10 */
+	srlx	%o0, 4, %g2
+
+	movrz	%g1, %g2, %o0		/* 11 */
+	add	%o2, %o3, %o2
+
+	movrz	%g1, 4, %o4		/* 12 */
+
+	and	%o0, 0x3, %g1		/* 13 */
+	srlx	%o0, 2, %g2
+
+	movrz	%g1, %g2, %o0		/* 14 */
+	add	%o2, %o4, %o2
+
+	movrz	%g1, 2, %o5		/* 15 */
+
+	and	%o0, 0x1, %g1		/* 16 */
+
+	add	%o2, %o5, %o2		/* 17 */
+	xor	%g1, 0x1, %g1
+
+	retl				/* 18 */
+	 add	%o2, %g1, %o0
+ENDPROC(ffs)
+ENDPROC(__ffs)
+
+	.section	.popc_6insn_patch, "ax"
+	.word		ffs
+	brz,pn	%o0, 98f
+	 neg	%o0, %g1
+	xnor	%o0, %g1, %o1
+	popc	%o1, %o0
+98:	retl
+	 nop
+	.word		__ffs
+	neg	%o0, %g1
+	xnor	%o0, %g1, %o1
+	popc	%o1, %o0
+	retl
+	 sub	%o0, 1, %o0
+	nop
+	.previous
-- 
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