Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / lib / reciprocal_div.c

diff --git a/kernel/lib/reciprocal_div.c b/kernel/lib/reciprocal_div.c
new file mode 100644 (file)
index 0000000..4641524
--- /dev/null
+++ b/kernel/lib/reciprocal_div.c
@@ -0,0 +1,27 @@
+#include <linux/kernel.h>
+#include <asm/div64.h>
+#include <linux/reciprocal_div.h>
+#include <linux/export.h>
+
+/*
+ * For a description of the algorithm please have a look at
+ * include/linux/reciprocal_div.h
+ */
+
+struct reciprocal_value reciprocal_value(u32 d)
+{
+       struct reciprocal_value R;
+       u64 m;
+       int l;
+
+       l = fls(d - 1);
+       m = ((1ULL << 32) * ((1ULL << l) - d));
+       do_div(m, d);
+       ++m;
+       R.m = (u32)m;
+       R.sh1 = min(l, 1);
+       R.sh2 = max(l - 1, 0);
+
+       return R;
+}
+EXPORT_SYMBOL(reciprocal_value);