1use crate::float::Float;
2use crate::int::Int;
3
4/// Returns `a` raised to the power `b`
5fn pow<F: Float>(a: F, b: i32) -> F {
6 let mut a: F = a;
7 let recip: bool = b < 0;
8 let mut pow: u32 = Int::abs_diff(self:b, other:0);
9 let mut mul: F = F::ONE;
10 loop {
11 if (pow & 1) != 0 {
12 mul *= a;
13 }
14 pow >>= 1;
15 if pow == 0 {
16 break;
17 }
18 a *= a;
19 }
20
21 if recip {
22 F::ONE / mul
23 } else {
24 mul
25 }
26}
27
28intrinsics! {
29 #[avr_skip]
30 pub extern "C" fn __powisf2(a: f32, b: i32) -> f32 {
31 pow(a, b)
32 }
33
34 #[avr_skip]
35 pub extern "C" fn __powidf2(a: f64, b: i32) -> f64 {
36 pow(a, b)
37 }
38
39 #[avr_skip]
40 #[ppc_alias = __powikf2]
41 #[cfg(f128_enabled)]
42 // FIXME(f16_f128): MSVC cannot build these until `__divtf3` is available in nightly.
43 #[cfg(not(target_env = "msvc"))]
44 pub extern "C" fn __powitf2(a: f128, b: i32) -> f128 {
45 pow(a, b)
46 }
47}
48