28 lines
657 B
Rust
28 lines
657 B
Rust
const FP_ILOGBNAN: i32 = -1 - 0x7fffffff;
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const FP_ILOGB0: i32 = FP_ILOGBNAN;
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#[cfg_attr(assert_no_panic, no_panic::no_panic)]
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pub fn ilogbf(x: f32) -> i32 {
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let mut i = x.to_bits();
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let e = ((i >> 23) & 0xff) as i32;
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if e == 0 {
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i <<= 9;
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if i == 0 {
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force_eval!(0.0 / 0.0);
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return FP_ILOGB0;
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}
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/* subnormal x */
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let mut e = -0x7f;
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while (i >> 31) == 0 {
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e -= 1;
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i <<= 1;
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}
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e
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} else if e == 0xff {
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force_eval!(0.0 / 0.0);
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if (i << 9) != 0 { FP_ILOGBNAN } else { i32::MAX }
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} else {
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e - 0x7f
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}
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}
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