math: add math library (currently only log_2)

kernel/kernel.mk

@@ -9,6 +9,7 @@ OBJS_$(d) := $(d)/atags.o \
 	$(d)/framebuffer.o \
 	$(d)/kmalloc.o \
 	$(d)/list.o \
+	$(d)/math.o \
 	$(d)/mm.o \
 	$(d)/mmu.o \
 	$(d)/print.o \

kernel/math.c

@@ -0,0 +1,28 @@
+/*
+    Copyright (C) 2012, Aaron Lindsay <aaron@aclindsay.com>
+
+    This file is part of Aedrix.
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <types.h>
+
+uint32 log(uint32 i) {
+	unsigned int l = 1;
+	while ((i = i>>1))
+		l++;
+	return l;
+}