StrafesNET/fixed_wide_vectors
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save one shr operation

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Quaternions 2024-08-29 15:21:10 -07:00
parent 95651d7091
commit 67c30b8535
1 changed files with 4 additions and 4 deletions
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8
fixed_wide/src/fixed_wide_traits.rs
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@ -70,15 +70,14 @@ impl<const CHUNKS:usize,Frac:Unsigned> Fixed<CHUNKS,Frac>
//0110.0000
//pow2 = 0100.0000
let mut pow2=Self{
bits:BInt::<CHUNKS>::ONE.shl((((CHUNKS as i32*64-Frac::I32-(self.bits.leading_zeros() as i32)+1)>>1)+Frac::I32) as u32),
bits:BInt::<CHUNKS>::ONE.shl(((((CHUNKS as i32*64-Frac::I32-(self.bits.leading_zeros() as i32)+1)>>1)+Frac::I32) as u32).saturating_sub(1)),
frac:PhantomData,
};
let mut result=pow2>>1;
let mut result=pow2;
//cheat to make the types match
let wide_self=self.wide_mul(Fixed::<CHUNKS,Frac>::ONE);
loop{
pow2>>=1;
if pow2==Self::ZERO{
break result;
}
@ -87,10 +86,11 @@ impl<const CHUNKS:usize,Frac:Unsigned> Fixed<CHUNKS,Frac>
//note that the implicit truncation in the multiply
//means that the algorithm can return a result which squares to a number greater than the input.
match wide_self.cmp(&new_result.wide_mul(new_result)){
core::cmp::Ordering::Less=>continue,
core::cmp::Ordering::Less=>(),
core::cmp::Ordering::Equal=>break new_result,
core::cmp::Ordering::Greater=>result=new_result,
}
pow2>>=1;
}
}
pub fn sqrt(self)->Self{