asm for log2

src/math/i386/log2.s

@@ -0,0 +1,7 @@
+.global log2
+.type log2,@function
+log2:
+	fld1
+	fldl 4(%esp)
+	fyl2x
+	ret

src/math/i386/log2f.s

@@ -0,0 +1,7 @@
+.global log2f
+.type log2f,@function
+log2f:
+	fld1
+	flds 4(%esp)
+	fyl2x
+	ret

src/math/i386/log2l.s

@@ -0,0 +1,7 @@
+.global log2l
+.type log2l,@function
+log2l:
+	fld1
+	fldt 4(%esp)
+	fyl2x
+	ret