bjorn3
51 lines
1.2 KiB
Rust
51 lines
1.2 KiB
Rust
use core::f32;
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/// Floor (f32)
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///
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/// Finds the nearest integer less than or equal to `x`.
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#[inline]
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#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
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pub fn floorf(x: f32) -> f32 {
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// On wasm32 we know that LLVM's intrinsic will compile to an optimized
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// `f32.floor` native instruction, so we can leverage this for both code size
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// and speed.
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llvm_intrinsically_optimized! {
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#[cfg(target_arch = "wasm32")] {
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return unsafe { ::core::intrinsics::floorf32(x) }
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}
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}
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let mut ui = x.to_bits();
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let e = (((ui >> 23) as i32) & 0xff) - 0x7f;
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if e >= 23 {
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return x;
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}
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if e >= 0 {
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let m: u32 = 0x007fffff >> e;
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if (ui & m) == 0 {
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return x;
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}
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force_eval!(x + f32::from_bits(0x7b800000));
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if ui >> 31 != 0 {
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ui += m;
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}
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ui &= !m;
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} else {
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force_eval!(x + f32::from_bits(0x7b800000));
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if ui >> 31 == 0 {
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ui = 0;
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} else if ui << 1 != 0 {
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return -1.0;
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}
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}
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f32::from_bits(ui)
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}
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#[cfg(test)]
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mod tests {
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#[test]
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fn no_overflow() {
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assert_eq!(super::floorf(0.5), 0.0);
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}
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}
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