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use core::f32;
/// Floor (f32)
///
/// Finds the nearest integer less than or equal to `x`.
#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
pub fn floorf(x: f32) -> f32 {
// On wasm32 we know that LLVM's intrinsic will compile to an optimized
// `f32.floor` native instruction, so we can leverage this for both code size
// and speed.
llvm_intrinsically_optimized! {
#[cfg(target_arch = "wasm32")] {
return unsafe { ::core::intrinsics::floorf32(x) }
}
}
let mut ui = x.to_bits();
let e = (((ui >> 23) as i32) & 0xff) - 0x7f;
if e >= 23 {
return x;
}
if e >= 0 {
let m: u32 = 0x007fffff >> e;
if (ui & m) == 0 {
return x;
}
force_eval!(x + f32::from_bits(0x7b800000));
if ui >> 31 != 0 {
ui += m;
}
ui &= !m;
} else {
force_eval!(x + f32::from_bits(0x7b800000));
if ui >> 31 == 0 {
ui = 0;
} else if ui << 1 != 0 {
return -1.0;
}
}
f32::from_bits(ui)
}
// PowerPC tests are failing on LLVM 13: https://github.com/rust-lang/rust/issues/88520
#[cfg(not(target_arch = "powerpc64"))]
#[cfg(test)]
mod tests {
use super::*;
use core::f32::*;
#[test]
fn sanity_check() {
assert_eq!(floorf(0.5), 0.0);
assert_eq!(floorf(1.1), 1.0);
assert_eq!(floorf(2.9), 2.0);
}
/// The spec: https://en.cppreference.com/w/cpp/numeric/math/floor
#[test]
fn spec_tests() {
// Not Asserted: that the current rounding mode has no effect.
assert!(floorf(NAN).is_nan());
for f in [0.0, -0.0, INFINITY, NEG_INFINITY].iter().copied() {
assert_eq!(floorf(f), f);
}
}
}
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