[PATCH v2 1/2] sparc64: Define SPARC default fls and __fls

[Vijay Kumar]

fls and __fls will now require boot time patching on T4
and above. Redefining these functions under arc/sparc/lib.

Signed-off-by: Vijay Kumar <vijay.ac.kumar@xxxxxxxxxx>
Reviewed-by: Babu Moger <babu.moger@xxxxxxxxxx>
---
 arch/sparc/include/asm/bitops_64.h |    7 +-
 arch/sparc/lib/Makefile            |    1 +
 arch/sparc/lib/fls.S               |  126 ++++++++++++++++++++++++++++++++++++
 3 files changed, 131 insertions(+), 3 deletions(-)

diff --git a/arch/sparc/include/asm/bitops_64.h b/arch/sparc/include/asm/bitops_64.h
index 2d52240..946c236 100644
--- a/arch/sparc/include/asm/bitops_64.h
+++ b/arch/sparc/include/asm/bitops_64.h
@@ -22,11 +22,12 @@
 void clear_bit(unsigned long nr, volatile unsigned long *addr);
 void change_bit(unsigned long nr, volatile unsigned long *addr);
 
+#define fls64(word)  (((word)?(__fls(word) + 1):0))
+int fls(unsigned int word);
+int __fls(unsigned long word);
+
 #include <asm-generic/bitops/non-atomic.h>
 
-#include <asm-generic/bitops/fls.h>
-#include <asm-generic/bitops/__fls.h>
-#include <asm-generic/bitops/fls64.h>
 
 #ifdef __KERNEL__
 
diff --git a/arch/sparc/lib/Makefile b/arch/sparc/lib/Makefile
index 07c03e7..eefbb9c 100644
--- a/arch/sparc/lib/Makefile
+++ b/arch/sparc/lib/Makefile
@@ -16,6 +16,7 @@ lib-$(CONFIG_SPARC64) += atomic_64.o
 lib-$(CONFIG_SPARC32) += lshrdi3.o ashldi3.o
 lib-$(CONFIG_SPARC32) += muldi3.o bitext.o cmpdi2.o
 lib-$(CONFIG_SPARC64) += multi3.o
+lib-$(CONFIG_SPARC64) += fls.o
 
 lib-$(CONFIG_SPARC64) += copy_page.o clear_page.o bzero.o
 lib-$(CONFIG_SPARC64) += csum_copy.o csum_copy_from_user.o csum_copy_to_user.o
diff --git a/arch/sparc/lib/fls.S b/arch/sparc/lib/fls.S
new file mode 100644
index 0000000..a19bff2
--- /dev/null
+++ b/arch/sparc/lib/fls.S
@@ -0,0 +1,126 @@
+/* fls.S: SPARC default fls and __fls definitions.
+ *
+ * SPARC default fls and __fls definitions, which follows the same
+ * algorithm as in generic fls() and __fls(). These functions will
+ * be boot time patched on T4 and onward.
+ */
+
+#include <asm/bitsperlong.h>
+#include <asm/export.h>
+
+	.text
+	.align	32
+
+	.global	fls, __fls
+	.type	fls,	#function
+	.type	__fls,	#function
+
+	.register	%g2, #scratch
+	.register	%g3, #scratch
+
+EXPORT_SYMBOL(__fls)
+EXPORT_SYMBOL(fls)
+
+fls:
+	brz,pn	%o0, 6f
+	 mov	0, %o1
+	sethi	%hi(0xffff0000), %g3
+	mov	%o0, %g2
+	andcc	%o0, %g3, %g0
+	be,pt	%icc, 8f
+	 mov	32, %o1
+	sethi	%hi(0xff000000), %g3
+	andcc	%g2, %g3, %g0
+	bne,pt	%icc, 3f
+	 sethi	%hi(0xf0000000), %g3
+	sll	%o0, 8, %o0
+1:
+	add	%o1, -8, %o1
+	sra	%o0, 0, %o0
+	mov	%o0, %g2
+2:
+	sethi	%hi(0xf0000000), %g3
+3:
+	andcc	%g2, %g3, %g0
+	bne,pt	%icc, 4f
+	 sethi	%hi(0xc0000000), %g3
+	sll	%o0, 4, %o0
+	add	%o1, -4, %o1
+	sra	%o0, 0, %o0
+	mov	%o0, %g2
+4:
+	andcc	%g2, %g3, %g0
+	be,a,pt	%icc, 7f
+	 sll	%o0, 2, %o0
+5:
+	xnor	%g0, %o0, %o0
+	srl	%o0, 31, %o0
+	sub	%o1, %o0, %o1
+6:
+	jmp	%o7 + 8
+	 sra	%o1, 0, %o0
+7:
+	add	%o1, -2, %o1
+	ba,pt	%xcc, 5b
+	 sra	%o0, 0, %o0
+8:
+	sll	%o0, 16, %o0
+	sethi	%hi(0xff000000), %g3
+	sra	%o0, 0, %o0
+	mov	%o0, %g2
+	andcc	%g2, %g3, %g0
+	bne,pt	%icc, 2b
+	 mov	16, %o1
+	ba,pt	%xcc, 1b
+	 sll	%o0, 8, %o0
+	.size	fls, .-fls
+
+__fls:
+#if BITS_PER_LONG == 64
+	mov	-1, %g2
+	sllx	%g2, 32, %g2
+	and	%o0, %g2, %g2
+	brnz,pt	%g2, 1f
+	 mov	63, %g1
+	sllx	%o0, 32, %o0
+#endif
+	mov	31, %g1
+1:
+	mov	-1, %g2
+	sllx	%g2, (BITS_PER_LONG-16), %g2
+	and	%o0, %g2, %g2
+	brnz,pt	%g2, 2f
+	 mov	-1, %g2
+	sllx	%o0, 16, %o0
+	add	%g1, -16, %g1
+2:
+	mov	-1, %g2
+	sllx	%g2, (BITS_PER_LONG-8), %g2
+	and	%o0, %g2, %g2
+	brnz,pt	%g2, 3f
+	 mov	-1, %g2
+	sllx	%o0, 8, %o0
+	add	%g1, -8, %g1
+3:
+	sllx	%g2, (BITS_PER_LONG-4), %g2
+	and	%o0, %g2, %g2
+	brnz,pt	%g2, 4f
+	 mov	-1, %g2
+	sllx	%o0, 4, %o0
+	add	%g1, -4, %g1
+4:
+	sllx	%g2, (BITS_PER_LONG-2), %g2
+	and	%o0, %g2, %g2
+	brnz,pt	%g2, 5f
+	 mov	-1, %g3
+	sllx	%o0, 2, %o0
+	add	%g1, -2, %g1
+5:
+	mov	0, %g2
+	sllx	%g3, (BITS_PER_LONG-1), %g3
+	and	%o0, %g3, %o0
+	movre	%o0, 1, %g2
+	sub	%g1, %g2, %g1
+	jmp	%o7+8
+	 sra	%g1, 0, %o0
+	.size	__fls, .-__fls
-- 
1.7.1