lambdaclass · FrancoGiachetta · Jan 3, 2025 · Dec 20, 2024 · Dec 20, 2024 · Dec 20, 2024
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -4,6 +4,8 @@
 
 #### [2.0.0-rc2] - 2024-12-12
 
+* feat: Add support for subtractions contenting references as right hand side operands [#1898](https://github.com/lambdaclass/cairo-vm/pull/1898)
+
 * fix: Change wildcard getrandom dependency.
 
 * Update starknet-crypto to 0.7.3, removing the old FieldElement completly in favour of the new Felt (that is Copy).

diff --git a/examples/custom_hint/custom_hint.cairo b/examples/custom_hint/custom_hint.cairo
@@ -1,6 +1,9 @@
 func main() {
-    let a = 17;
-    // Use custom hint to print the value of a
+    alloc_locals;
+    local tmp = 3;
+    let a = 17 - tmp;
+
     %{ print(ids.a) %}
+
     return ();
 }
diff --git a/vm/src/hint_processor/builtin_hint_processor/hint_utils.rs b/vm/src/hint_processor/builtin_hint_processor/hint_utils.rs
@@ -149,7 +149,7 @@ mod tests {
     fn get_ptr_from_var_name_immediate_value() {
         let mut vm = vm!();
         vm.segments = segments![((1, 0), (0, 0))];
-        let mut hint_ref = HintReference::new(0, 0, true, false);
+        let mut hint_ref = HintReference::new(0, 0, true, false, true);
         hint_ref.offset2 = OffsetValue::Value(2);
         let ids_data = HashMap::from([("imm".to_string(), hint_ref)]);
 

diff --git a/vm/src/hint_processor/builtin_hint_processor/math_utils.rs b/vm/src/hint_processor/builtin_hint_processor/math_utils.rs
@@ -2053,8 +2053,14 @@ mod tests {
         //Create ids
         let ids_data = HashMap::from([
             ("value".to_string(), HintReference::new_simple(-4)),
-            ("low".to_string(), HintReference::new(-3, 0, true, true)),
-            ("high".to_string(), HintReference::new(-3, 1, true, true)),
+            (
+                "low".to_string(),
+                HintReference::new(-3, 0, true, true, true),
+            ),
+            (
+                "high".to_string(),
+                HintReference::new(-3, 1, true, true, true),
+            ),
         ]);
         //Execute the hint
         assert_matches!(
@@ -2131,8 +2137,14 @@ mod tests {
         //Create ids_data & hint_data
         let ids_data = HashMap::from([
             ("value".to_string(), HintReference::new_simple(-4)),
-            ("low".to_string(), HintReference::new(-3, 0, true, true)),
-            ("high".to_string(), HintReference::new(-3, 1, true, true)),
+            (
+                "low".to_string(),
+                HintReference::new(-3, 0, true, true, true),
+            ),
+            (
+                "high".to_string(),
+                HintReference::new(-3, 1, true, true, true),
+            ),
         ]);
 
         //Execute the hint
@@ -2175,8 +2187,14 @@ mod tests {
         //Create ids_data & hint_data
         let ids_data = HashMap::from([
             ("value".to_string(), HintReference::new_simple(-4)),
-            ("low".to_string(), HintReference::new(-3, 0, true, true)),
-            ("high".to_string(), HintReference::new(-3, 1, true, true)),
+            (
+                "low".to_string(),
+                HintReference::new(-3, 0, true, true, true),
+            ),
+            (
+                "high".to_string(),
+                HintReference::new(-3, 1, true, true, true),
+            ),
         ]);
         //Execute the hint
         assert_matches!(
@@ -2213,8 +2231,14 @@ mod tests {
         //Create ids_data & hint_data
         let ids_data = HashMap::from([
             ("value".to_string(), HintReference::new_simple(-4)),
-            ("low".to_string(), HintReference::new(-3, 0, true, true)),
-            ("high".to_string(), HintReference::new(-3, 1, true, true)),
+            (
+                "low".to_string(),
+                HintReference::new(-3, 0, true, true, true),
+            ),
+            (
+                "high".to_string(),
+                HintReference::new(-3, 1, true, true, true),
+            ),
         ]);
         //Execute the hint
         assert_matches!(
@@ -2251,8 +2275,14 @@ mod tests {
         //Create ids
         let ids_data = HashMap::from([
             ("value".to_string(), HintReference::new_simple(-4)),
-            ("low".to_string(), HintReference::new(-3, 0, true, true)),
-            ("high".to_string(), HintReference::new(-3, 1, true, true)),
+            (
+                "low".to_string(),
+                HintReference::new(-3, 0, true, true, true),
+            ),
+            (
+                "high".to_string(),
+                HintReference::new(-3, 1, true, true, true),
+            ),
         ]);
         //Execute the hint
         assert_matches!(
@@ -2277,8 +2307,14 @@ mod tests {
         //Create ids
         let ids_data = HashMap::from([
             ("value".to_string(), HintReference::new_simple(-4)),
-            ("low".to_string(), HintReference::new(-3, 0, true, true)),
-            ("high".to_string(), HintReference::new(-3, 1, true, true)),
+            (
+                "low".to_string(),
+                HintReference::new(-3, 0, true, true, true),
+            ),
+            (
+                "high".to_string(),
+                HintReference::new(-3, 1, true, true, true),
+            ),
         ]);
         //Execute the hint
         assert_matches!(
@@ -2315,8 +2351,14 @@ mod tests {
         //Create ids
         let ids_data = HashMap::from([
             ("value".to_string(), HintReference::new_simple(-4)),
-            ("low".to_string(), HintReference::new(-3, 0, true, true)),
-            ("high".to_string(), HintReference::new(-3, 1, true, true)),
+            (
+                "low".to_string(),
+                HintReference::new(-3, 0, true, true, true),
+            ),
+            (
+                "high".to_string(),
+                HintReference::new(-3, 1, true, true, true),
+            ),
         ]);
         //Execute the hint
         assert_matches!(

diff --git a/vm/src/hint_processor/hint_processor_definition.rs b/vm/src/hint_processor/hint_processor_definition.rs
@@ -112,7 +112,7 @@ pub struct HintReference {
 impl HintReference {
     pub fn new_simple(offset1: i32) -> Self {
         HintReference {
-            offset1: OffsetValue::Reference(Register::FP, offset1, false),
+            offset1: OffsetValue::Reference(Register::FP, offset1, false, true),
             offset2: OffsetValue::Value(0),
             ap_tracking_data: None,
             outer_dereference: true,
@@ -121,9 +121,15 @@ impl HintReference {
         }
     }
 
-    pub fn new(offset1: i32, offset2: i32, inner_dereference: bool, dereference: bool) -> Self {
+    pub fn new(
+        offset1: i32,
+        offset2: i32,
+        inner_dereference: bool,
+        dereference: bool,
+        is_positive: bool,
+    ) -> Self {
         HintReference {
-            offset1: OffsetValue::Reference(Register::FP, offset1, inner_dereference),
+            offset1: OffsetValue::Reference(Register::FP, offset1, inner_dereference, is_positive),
             offset2: OffsetValue::Value(offset2),
             ap_tracking_data: None,
             outer_dereference: dereference,
@@ -145,8 +151,8 @@ impl From<Reference> for HintReference {
                 &reference.value_address.offset1,
                 &reference.value_address.offset2,
             ) {
-                (OffsetValue::Reference(Register::AP, _, _), _)
-                | (_, OffsetValue::Reference(Register::AP, _, _)) => {
+                (OffsetValue::Reference(Register::AP, _, _, _), _)
+                | (_, OffsetValue::Reference(Register::AP, _, _, _)) => {
                     Some(reference.ap_tracking_data.clone())
                 }
                 _ => None,

diff --git a/vm/src/hint_processor/hint_processor_utils.rs b/vm/src/hint_processor/hint_processor_utils.rs
@@ -70,7 +70,12 @@
         &hint_reference.ap_tracking_data,
         ap_tracking,
     )?;
-    let mut val = offset1.add(&offset2).ok()?;
+    let mut val = match hint_reference.offset2 {
+        OffsetValue::Reference(_, _, _, true)
+        | OffsetValue::Immediate(_)
+        | OffsetValue::Value(_) => offset1.add(&offset2).ok()?,
+        OffsetValue::Reference(_, _, _, false) => offset1.sub(&offset2).ok()?,
+    };
     if hint_reference.inner_dereference && hint_reference.outer_dereference {
         val = vm.get_maybe(&val)?;
     }
@@ -139,7 +144,7 @@
     match offset_value {
         OffsetValue::Immediate(f) => Some(f.into()),
         OffsetValue::Value(v) => Some(Felt252::from(*v).into()),
-        OffsetValue::Reference(register, offset, deref) => {
+        OffsetValue::Reference(register, offset, deref, _) => {
             let addr = (if matches!(register, Register::FP) {
                 vm.get_fp()
             } else {
@@ -176,7 +181,7 @@
         // Reference: cast(2, felt)
         let mut vm = vm!();
         vm.segments = segments![((1, 0), 0)];
-        let mut hint_ref = HintReference::new(0, 0, false, false);
+        let mut hint_ref = HintReference::new(0, 0, false, false, true);
         hint_ref.offset1 = OffsetValue::Immediate(Felt252::from(2));
 
         assert_eq!(
@@ -191,8 +196,8 @@
     fn get_offset_value_reference_valid() {
         let mut vm = vm!();
         vm.segments = segments![((1, 0), 0)];
-        let mut hint_ref = HintReference::new(0, 0, false, true);
-        hint_ref.offset1 = OffsetValue::Reference(Register::FP, 2_i32, false);
+        let mut hint_ref = HintReference::new(0, 0, false, true, true);
+        hint_ref.offset1 = OffsetValue::Reference(Register::FP, 2_i32, false, true);
 
         assert_matches!(
             get_offset_value(&vm, &hint_ref.offset1, &hint_ref.ap_tracking_data, &ApTracking::new()),
@@ -205,8 +210,8 @@
     fn get_offset_value_invalid() {
         let mut vm = vm!();
         vm.segments = segments![((1, 0), 0)];
-        let mut hint_ref = HintReference::new(0, 0, false, true);
-        hint_ref.offset1 = OffsetValue::Reference(Register::FP, -2_i32, false);
+        let mut hint_ref = HintReference::new(0, 0, false, true, true);
+        hint_ref.offset1 = OffsetValue::Reference(Register::FP, -2_i32, false, true);
 
         assert_matches!(
             get_offset_value(
@@ -228,7 +233,7 @@
         assert_matches!(
             get_ptr_from_reference(
                 &vm,
-                &HintReference::new(0, 0, false, false),
+                &HintReference::new(0, 0, false, false, true),
                 &ApTracking::new()
             ),
             Ok(x) if x == relocatable!(1, 0)
@@ -244,7 +249,7 @@
         assert_matches!(
             get_ptr_from_reference(
                 &vm,
-                &HintReference::new(0, 0, false, true),
+                &HintReference::new(0, 0, false, true, true),
                 &ApTracking::new()
             ),
             Ok(x) if x == relocatable!(3, 0)
@@ -256,7 +261,7 @@
     fn get_ptr_from_reference_with_dereference_and_imm() {
         let mut vm = vm!();
         vm.segments = segments![((1, 0), (4, 0))];
-        let mut hint_ref = HintReference::new(0, 0, true, false);
+        let mut hint_ref = HintReference::new(0, 0, true, false, true);
         hint_ref.offset2 = OffsetValue::Value(2);
 
         assert_matches!(
@@ -270,7 +275,7 @@
     fn compute_addr_from_reference_no_regiter_in_reference() {
         let mut vm = vm!();
         vm.segments = segments![((1, 0), (4, 0))];
-        let mut hint_reference = HintReference::new(0, 0, false, false);
+        let mut hint_reference = HintReference::new(0, 0, false, false, true);
         hint_reference.offset1 = OffsetValue::Immediate(Felt252::from(2_i32));
 
         assert!(compute_addr_from_reference(&hint_reference, &vm, &ApTracking::new()).is_none());
@@ -282,8 +287,8 @@
         let mut vm = vm!();
         vm.segments = segments![((1, 0), 4)];
         // vm.run_context.fp = -1;
-        let mut hint_reference = HintReference::new(0, 0, false, false);
-        hint_reference.offset1 = OffsetValue::Reference(Register::FP, -1, true);
+        let mut hint_reference = HintReference::new(0, 0, false, false, true);
+        hint_reference.offset1 = OffsetValue::Reference(Register::FP, -1, true, true);
 
         assert_matches!(
             compute_addr_from_reference(&hint_reference, &vm, &ApTracking::new()),
@@ -356,7 +361,7 @@
             ((0, 5), 3)       // [[[fp + 2] + 2]] -> [(0, 5)] -> 3
         ];
         let hint_ref = HintReference {
-            offset1: OffsetValue::Reference(Register::FP, 2, true),
+            offset1: OffsetValue::Reference(Register::FP, 2, true, true),
             offset2: OffsetValue::Value(2),
             outer_dereference: true,
             inner_dereference: true,
@@ -381,7 +386,7 @@
         ];
         // [fp + 4] + (-5) = 8 - 5 = 3
         let hint_ref = HintReference {
-            offset1: OffsetValue::Reference(Register::FP, 4, true),
+            offset1: OffsetValue::Reference(Register::FP, 4, true, true),
             offset2: OffsetValue::Immediate(Felt252::from(-5)),
             outer_dereference: false,
             inner_dereference: false,

diff --git a/vm/src/serde/deserialize_program.rs b/vm/src/serde/deserialize_program.rs
@@ -275,7 +275,7 @@ pub struct Reference {
 pub enum OffsetValue {
     Immediate(Felt252),
     Value(i32),
-    Reference(Register, i32, bool),
+    Reference(Register, i32, bool, bool),
 }
 
 #[cfg_attr(feature = "test_utils", derive(Arbitrary))]
@@ -714,7 +714,7 @@ mod tests {
                     },
                     pc: Some(0),
                     value_address: ValueAddress {
-                        offset1: OffsetValue::Reference(Register::FP, -4, false),
+                        offset1: OffsetValue::Reference(Register::FP, -4, false, true),
                         offset2: OffsetValue::Value(0),
                         outer_dereference: true,
                         inner_dereference: false,
@@ -728,7 +728,7 @@ mod tests {
                     },
                     pc: Some(0),
                     value_address: ValueAddress {
-                        offset1: OffsetValue::Reference(Register::FP, -3, false),
+                        offset1: OffsetValue::Reference(Register::FP, -3, false, true),
                         offset2: OffsetValue::Value(0),
                         outer_dereference: true,
                         inner_dereference: false,
@@ -742,7 +742,7 @@ mod tests {
                     },
                     pc: Some(0),
                     value_address: ValueAddress {
-                        offset1: OffsetValue::Reference(Register::FP, -3, true),
+                        offset1: OffsetValue::Reference(Register::FP, -3, true, true),
                         offset2: OffsetValue::Immediate(Felt252::from(2)),
                         outer_dereference: false,
                         inner_dereference: false,
@@ -756,7 +756,7 @@ mod tests {
                     },
                     pc: Some(0),
                     value_address: ValueAddress {
-                        offset1: OffsetValue::Reference(Register::FP, 0, false),
+                        offset1: OffsetValue::Reference(Register::FP, 0, false, true),
                         offset2: OffsetValue::Value(0),
                         outer_dereference: true,
                         inner_dereference: false,