initial

1 files changed, 29 insertions, 0 deletions

diff --git a/libk/src/math/fact.c b/libk/src/math/fact.c
new file mode 100644
index 0000000..a146e4d
--- /dev/null
+++ b/libk/src/math/fact.c
@@ -0,0 +1,29 @@
+#include <math.h>
+
+static unsigned int FACT_TABLE[] = {
+    1,          // 0
+    1,          // 1
+    2,          // 2
+    6,          // 3
+    24,         // 4
+    120,        // 5
+    720,        // 6
+    5040,       // 7
+    40320,      // 8
+    362880,     // 9
+    3628800,    // 10
+    39916800,   // 11
+    479001600,  // 12
+};
+
+unsigned long long fact(unsigned int num) {
+    if (num < 13) {
+        return FACT_TABLE[num];
+    }
+    unsigned long long l = FACT_TABLE[12];
+    for (unsigned int i = 12; i < num;) {
+        i++;
+        l *= i;
+    }
+    return l;
+}