dev: implement Zero for u384 (#6329)

starkware-libs · Sep 4, 2024 · 7eb3c15 · 7eb3c15
1 parent 74c1bdc
commit 7eb3c15
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diff --git a/corelib/src/circuit.cairo b/corelib/src/circuit.cairo
@@ -571,3 +571,17 @@ impl U384TryIntoU256 of TryInto<u384, u256> {
         conversions::try_into_u256(self)
     }
 }
+
+impl U384Zero of crate::num::traits::Zero<u384> {
+    fn zero() -> u384 {
+        u384 { limb0: 0, limb1: 0, limb2: 0, limb3: 0 }
+    }
+
+    fn is_zero(self: @u384) -> bool {
+        *self == Self::zero()
+    }
+
+    fn is_non_zero(self: @u384) -> bool {
+        !self.is_zero()
+    }
+}
diff --git a/corelib/src/test/circuit_test.cairo b/corelib/src/test/circuit_test.cairo
@@ -4,6 +4,7 @@ use crate::circuit::{
     AddInputResultTrait, CircuitInputs,
 };
 
+use crate::num::traits::Zero;
 use crate::traits::TryInto;
 
 #[test]
@@ -133,3 +134,10 @@ fn test_fill_inputs_loop() {
     let modulus = TryInto::<_, CircuitModulus>::try_into([55, 0, 0, 0]).unwrap();
     circuit_inputs.done().eval(modulus).unwrap();
 }
+
+#[test]
+fn test_u384_zero() {
+    assert_eq!(Zero::zero(), u384 { limb0: 0, limb1: 0, limb2: 0, limb3: 0 });
+    assert!(Zero::is_zero(@u384 { limb0: 0, limb1: 0, limb2: 0, limb3: 0 }));
+    assert!(Zero::is_non_zero(@u384 { limb0: 0, limb1: 1, limb2: 0, limb3: 0 }));
+}