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add merge_unbias

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This commit is contained in:
numzero 2025-11-02 02:41:44 +03:00
parent f596505bd7
commit 4c2f02cfeb
1 changed files with 32 additions and 0 deletions
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32
src/lib.rs
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@ -38,6 +38,23 @@ impl F8 {
assert!(e <= E_STORAGE_MAX); assert!(e <= E_STORAGE_MAX);
Self((e << M_BITS) | m) Self((e << M_BITS) | m)
} }
fn merge_unbias(in_m: u8, in_e: i8) -> Self {
if in_m == 0 {
return Self(0);
}
let base_e = in_m.ilog2() as u8;
let off = base_e as i8 - M_BITS as i8;
let m = if off >= 0 { in_m >> off } else { in_m << -off };
let e = (base_e as i8) + in_e + (E_BIAS as i8);
if e < 0 {
return Self(0);
}
if e > E_STORAGE_MAX as i8 {
return Self(0xff);
}
Self::merge(m & M_STORAGE_MAX, e as u8)
}
} }
impl std::fmt::Binary for F8 { impl std::fmt::Binary for F8 {
@ -134,6 +151,21 @@ mod tests {
} }
} }
#[test]
fn test_merge() {
assert_eq!(f32::from(F8::merge_unbias(0, 0)), 0.0);
assert_eq!(f32::from(F8::merge_unbias(1, 0)), 1.0);
assert_eq!(f32::from(F8::merge_unbias(1, 1)), 2.0);
assert_eq!(f32::from(F8::merge_unbias(1, -1)), 0.5);
assert_eq!(f32::from(F8::merge_unbias(3, 0)), 3.0);
assert_eq!(f32::from(F8::merge_unbias(3, 1)), 6.0);
assert_eq!(f32::from(F8::merge_unbias(3, -1)), 1.5);
assert_eq!(
f32::from(F8::merge_unbias(EXACT_INT_MAX, 0)),
EXACT_INT_MAX as f32
);
}
#[test] #[test]
fn test_display() { fn test_display() {
fn fmt_split(m: u8, e: u8) -> String { fn fmt_split(m: u8, e: u8) -> String {