fix: fix wrong constant case detection in three_bit_cond_neg_lookup

src/fields/fp/mod.rs

@@ -979,7 +979,7 @@ impl ThreeBitCondNegLookupGadget for FpVar {
         debug_assert_eq!(b.len(), 3);
         debug_assert_eq!(c.len(), 4);
 
-        if !b.cs().or(b0b1.cs()).is_none() {
+        if b.cs().or(b0b1.cs()).is_none() {
             // We only have constants
 
             let lsb = usize::from(b[0].value()?);