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Don't use a macro for pow calculation

master
est31 2017-09-14 01:59:02 +02:00
parent 8313cec597
commit 72ed4c8bce
1 changed files with 13 additions and 9 deletions
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22
src/float/pow.rs
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@ -1,11 +1,12 @@
use int::Int; use int::Int;
use float::Float;
/// Returns `a` raised to the power `b` trait Pow: Float {
macro_rules! pow { /// Returns `a` raised to the power `b`
($a: expr, $b: expr) => ({ fn pow(self, mut b: i32) -> Self {
let (mut a, mut b) = ($a, $b); let mut a = self;
let recip = b < 0; let recip = b < 0;
let mut r = 1.0; let mut r = Self::ONE;
loop { loop {
if (b & 1) != 0 { if (b & 1) != 0 {
r *= a; r *= a;
@ -18,19 +19,22 @@ macro_rules! pow {
} }
if recip { if recip {
1.0 / r Self::ONE / r
} else { } else {
r r
} }
}) }
} }
impl Pow for f32 {}
impl Pow for f64 {}
intrinsics! { intrinsics! {
pub extern "C" fn __powisf2(a: f32, b: i32) -> f32 { pub extern "C" fn __powisf2(a: f32, b: i32) -> f32 {
pow!(a, b) a.pow(b)
} }
pub extern "C" fn __powidf2(a: f64, b: i32) -> f64 { pub extern "C" fn __powidf2(a: f64, b: i32) -> f64 {
pow!(a, b) a.pow(b)
} }
} }