diff options
Diffstat (limited to 'vendor/compiler_builtins/libm/src/math/acoshf.rs')
-rw-r--r-- | vendor/compiler_builtins/libm/src/math/acoshf.rs | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/vendor/compiler_builtins/libm/src/math/acoshf.rs b/vendor/compiler_builtins/libm/src/math/acoshf.rs new file mode 100644 index 000000000..0879e1edb --- /dev/null +++ b/vendor/compiler_builtins/libm/src/math/acoshf.rs @@ -0,0 +1,25 @@ +use super::{log1pf, logf, sqrtf}; + +const LN2: f32 = 0.693147180559945309417232121458176568; + +/// Inverse hyperbolic cosine (f32) +/// +/// Calculates the inverse hyperbolic cosine of `x`. +/// Is defined as `log(x + sqrt(x*x-1))`. +/// `x` must be a number greater than or equal to 1. +pub fn acoshf(x: f32) -> f32 { + let u = x.to_bits(); + let a = u & 0x7fffffff; + + if a < 0x3f800000 + (1 << 23) { + /* |x| < 2, invalid if x < 1 or nan */ + /* up to 2ulp error in [1,1.125] */ + return log1pf(x - 1.0 + sqrtf((x - 1.0) * (x - 1.0) + 2.0 * (x - 1.0))); + } + if a < 0x3f800000 + (12 << 23) { + /* |x| < 0x1p12 */ + return logf(2.0 * x - 1.0 / (x + sqrtf(x * x - 1.0))); + } + /* x >= 0x1p12 */ + return logf(x) + LN2; +} |