improve failure mode

fixed_wide/src/fixed.rs

@@ -155,24 +155,23 @@ impl_shift_operator!( Fixed, Shr, shr, Self );
 
 impl<const CHUNKS:usize,Frac:Unsigned> Fixed<CHUNKS,Frac>{
 	pub fn sqrt_unchecked(self)->Self{
-		let mut pow2=if self==Self::ZERO{
+		//find pow2 more powerful than self
-			return Self::ZERO;
+		let mut pow2=if Self::ONE<self{
-		}else if self<Self::ONE{
+			let mut pow2=Self::TWO;//1<self is so bake one iteration
-			//find pow2 more powerful than self
+			while pow2<=self{
+				pow2<<=1;
+			}
+			pow2
+		}else if Self::ONE==self{
+			return Self::ONE;
+		}else if Self::ZERO<self{
 			let mut pow2=Self::ONE;
 			while self<=pow2{
 				pow2>>=1;
 			}
 			pow2
-		}else if self==Self::ONE{
+		}else{//either 0==self or self is negative
-			return Self::ONE;
+			return Self::ZERO;
-		}else{
-			//find pow2 more powerful than self
-			let mut pow2=Self::ONE;
-			while pow2<=self{
-				pow2<<=1;
-			}
-			pow2
 		};
 		let mut result=pow2;
 		while pow2!=Self::ZERO{