Added some additional fast math functions.

src/math.rs

@@ -142,10 +142,24 @@ pub fn fast_pow2(p: f32) -> f32 {
     unsafe { transmute_copy::<u32, f32>(&i) }
 }
 
+pub fn fast_log2(x: f32) -> f32 {
+    use std::mem::transmute_copy;
+
+    let xi = unsafe { transmute_copy::<f32, u32>(&x) };
+    let y = xi as f32 * 1.1920928955078125e-7;
+    let mx = unsafe { transmute_copy::<u32, f32>(&((xi & 0x007FFFFF) | 0x3f000000)) };
+
+    return y - 124.22551499 - 1.498030302 * mx - 1.72587999 / (0.3520887068 + mx);
+}
+
 pub fn fast_exp(p: f32) -> f32 {
     fast_pow2(1.442695040 * p)
 }
 
+pub fn fast_pow(x: f32, p: f32) -> f32 {
+    fast_pow2(p * fast_log2(x))
+}
+
 pub fn faster_pow2(p: f32) -> f32 {
     use std::mem::transmute_copy;
 
@@ -159,6 +173,7 @@ pub fn faster_exp(p: f32) -> f32 {
     faster_pow2(1.442695040 * p)
 }
 
+
 // End of adapted code
 //----------------------------------------------------------------