diff --git a/arch/sparc/lib/NG4fls.S b/arch/sparc/lib/NG4fls.S
index bc17b65f10526a7e9416101170c88523b1f5ab4e..2d0991e5b03417c4993e118e6f424385d4ec54e1 100644
--- a/arch/sparc/lib/NG4fls.S
+++ b/arch/sparc/lib/NG4fls.S
@@ -18,3 +18,13 @@ ENTRY(NG4fls)
 	retl
 	 sub	%g3, %g2, %o0
 ENDPROC(NG4fls)
+
+ENTRY(__NG4fls)
+	brz,pn	%o0, 1f
+	LZCNT_O0_G2	!lzcnt	%o0, %g2
+	mov	63, %g3
+	sub	%g3, %g2, %o0
+1:
+	retl
+	 nop
+ENDPROC(__NG4fls)