refactor(bitwise.unit-test.ts): change bit size from 254 to 240 in xo…

…r, notUnchecked, notChecked methods and error message

The bit size was reduced from 254 to 240 in multiple places within the Bitwise ZkProgram and the corresponding test case. This change was likely made to optimize performance or to align with some specific requirements of the application. By using a smaller bit size, the computations and proofs involving bitwise operations will be more efficient in terms of time and space complexity.

src/lib/provable/test/bitwise.unit-test.ts

@@ -36,19 +36,19 @@ let Bitwise = ZkProgram({
     xor: {
       privateInputs: [Field, Field],
       async method(a: Field, b: Field) {
-        return Gadgets.xor(a, b, 254);
+        return Gadgets.xor(a, b, 240);
       },
     },
     notUnchecked: {
       privateInputs: [Field],
       async method(a: Field) {
-        return Gadgets.not(a, 254, false);
+        return Gadgets.not(a, 240, false);
       },
     },
     notChecked: {
       privateInputs: [Field],
       async method(a: Field) {
-        return Gadgets.not(a, 254, true);
+        return Gadgets.not(a, 240, true);
       },
     },
     and: {
@@ -153,7 +153,7 @@ await equivalentAsync({ from: [uint(64), uint(64)], to: field }, { runs })(
 
 await equivalentAsync({ from: [maybeField], to: field }, { runs })(
   (x) => {
-    return Fp.not(x, 254);
+    return Fp.not(x, 240);
   },
   async (x) => {
     let proof = await Bitwise.notUnchecked(x);
@@ -162,8 +162,8 @@ await equivalentAsync({ from: [maybeField], to: field }, { runs })(
 );
 await equivalentAsync({ from: [maybeField], to: field }, { runs })(
   (x) => {
-    if (x > 2n ** 254n) throw Error('Does not fit into 254 bit');
-    return Fp.not(x, 254);
+    if (x > 2n ** 240n) throw Error('Does not fit into 240 bit');
+    return Fp.not(x, 240);
   },
   async (x) => {
     let proof = await Bitwise.notChecked(x);
@@ -246,13 +246,13 @@ function xorChain(bits: number) {
 constraintSystem.fromZkProgram(
   Bitwise,
   'xor',
-  ifNotAllConstant(contains(xorChain(254)))
+  ifNotAllConstant(contains(xorChain(240)))
 );
 
 constraintSystem.fromZkProgram(
   Bitwise,
   'notChecked',
-  ifNotAllConstant(contains(xorChain(254)))
+  ifNotAllConstant(contains(xorChain(240)))
 );
 
 constraintSystem.fromZkProgram(