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Diffstat (limited to 'vendor/compiler_builtins/src/float/pow.rs')
-rw-r--r-- | vendor/compiler_builtins/src/float/pow.rs | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/vendor/compiler_builtins/src/float/pow.rs b/vendor/compiler_builtins/src/float/pow.rs new file mode 100644 index 000000000..a75340c30 --- /dev/null +++ b/vendor/compiler_builtins/src/float/pow.rs @@ -0,0 +1,36 @@ +use float::Float; +use int::Int; + +/// Returns `a` raised to the power `b` +fn pow<F: Float>(a: F, b: i32) -> F { + let mut a = a; + let recip = b < 0; + let mut pow = Int::abs_diff(b, 0); + let mut mul = F::ONE; + loop { + if (pow & 1) != 0 { + mul *= a; + } + pow >>= 1; + if pow == 0 { + break; + } + a *= a; + } + + if recip { + F::ONE / mul + } else { + mul + } +} + +intrinsics! { + pub extern "C" fn __powisf2(a: f32, b: i32) -> f32 { + pow(a, b) + } + + pub extern "C" fn __powidf2(a: f64, b: i32) -> f64 { + pow(a, b) + } +} |