feat(hints): Implement NewHint#38 (#1036)

* Add test

* Ignore builtin segments in get_memory_holes

* Improve test

* Add memory holes check for cairo_run_test tests

* Fix broken condition

* Make memory_holes check optional & customizable

* Fix bounds

* Add a test with deliberately created memory holes

* Fix test value

* Remove duplicated tests + add memory hole value to some tests

* Add memory holes value + remove duplicated tests + fix typo

* Fix test values

* Add changelog entry

* Link PR in Changelog

* Mark breaking change in changelog

* fmt

* Fix test value

* Fix codecov-patch diff

* Add hint code

* Add integration test

* Add untracked file

* Add changelog entry

* Rename hint

* Fix test

* Fix test

* Add hint code + hint impl + unit test

* fmt

* Add integration test

* Add changelog entry

* Remove indent from hint string

* Add wasm import

CHANGELOG.md

@@ -2,6 +2,23 @@
 
 #### Upcoming Changes
 
+* Implement hint on ec_recover.json whitelist [#1036](https://github.com/lambdaclass/cairo-rs/pull/1036):
+
+    `BuiltinHintProcessor` now supports the following hint:
+
+    ```python
+
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import pack
+        from starkware.python.math_utils import div_mod, safe_div
+
+        a = pack(ids.a, PRIME)
+        b = pack(ids.b, PRIME)
+        value = res = a - b
+    %}
+
+    ```
+
 * Implement hint on ec_recover.json whitelist [#1032](https://github.com/lambdaclass/cairo-rs/pull/1032):
 
     `BuiltinHintProcessor` now supports the following hint:

cairo_programs/ec_recover.cairo

@@ -6,6 +6,7 @@ func test_div_mod_n_packed_hint{range_check_ptr: felt}() {
     tempvar n = BigInt3(177, 0, 0);
     tempvar x = BigInt3(25, 0, 0);
     tempvar s = BigInt3(5, 0, 0);
+
     %{
         from starkware.cairo.common.cairo_secp.secp_utils import pack
         from starkware.python.math_utils import div_mod, safe_div
@@ -18,10 +19,32 @@ func test_div_mod_n_packed_hint{range_check_ptr: felt}() {
 
     let (res) = nondet_bigint3();
     assert res = BigInt3(5,0,0);
+
+    return();
+}
+
+func test_sub_a_b_hint{range_check_ptr: felt}() {
+
+    tempvar a = BigInt3(100, 0, 0);
+    tempvar b = BigInt3(25, 0, 0);
+
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import pack
+        from starkware.python.math_utils import div_mod, safe_div
+
+        a = pack(ids.a, PRIME)
+        b = pack(ids.b, PRIME)
+        value = res = a - b
+    %}
+
+    let (res) = nondet_bigint3();
+    assert res = BigInt3(75,0,0);
+
     return();
 }
 
 func main{range_check_ptr: felt}() {
     test_div_mod_n_packed_hint();
+    test_sub_a_b_hint();
     return();
 }

src/hint_processor/builtin_hint_processor/builtin_hint_processor_definition.rs

@@ -85,7 +85,7 @@ use felt::Felt252;
 #[cfg(feature = "skip_next_instruction_hint")]
 use crate::hint_processor::builtin_hint_processor::skip_next_instruction::skip_next_instruction;
 
-use super::ec_recover::ec_recover_divmod_n_packed;
+use super::ec_recover::{ec_recover_divmod_n_packed, ec_recover_sub_a_b};
 use super::field_arithmetic::uint384_div;
 use super::vrf::inv_mod_p_uint512::inv_mod_p_uint512;
 
@@ -592,6 +592,9 @@ impl HintProcessor for BuiltinHintProcessor {
                 &hint_data.ids_data,
                 &hint_data.ap_tracking,
             ),
+            hint_code::EC_RECOVER_SUB_A_B => {
+                ec_recover_sub_a_b(vm, exec_scopes, &hint_data.ids_data, &hint_data.ap_tracking)
+            }
             #[cfg(feature = "skip_next_instruction_hint")]
             hint_code::SKIP_NEXT_INSTRUCTION => skip_next_instruction(vm),
             code => Err(HintError::UnknownHint(code.to_string())),

src/hint_processor/builtin_hint_processor/ec_recover.rs

@@ -36,6 +36,31 @@ pub fn ec_recover_divmod_n_packed(
     Ok(())
 }
 
+/* Implements Hint:
+%{
+    from starkware.cairo.common.cairo_secp.secp_utils import pack
+    from starkware.python.math_utils import div_mod, safe_div
+
+    a = pack(ids.x, PRIME)
+    b = pack(ids.s, PRIME)
+    value = res = a - b
+%}
+ */
+pub fn ec_recover_sub_a_b(
+    vm: &mut VirtualMachine,
+    exec_scopes: &mut ExecutionScopes,
+    ids_data: &HashMap<String, HintReference>,
+    ap_tracking: &ApTracking,
+) -> Result<(), HintError> {
+    let a = pack(BigInt3::from_var_name("a", vm, ids_data, ap_tracking)?);
+    let b = pack(BigInt3::from_var_name("b", vm, ids_data, ap_tracking)?);
+
+    let value = a - b;
+    exec_scopes.insert_value("value", value.clone());
+    exec_scopes.insert_value("res", value);
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use num_bigint::BigInt;
@@ -99,4 +124,38 @@ mod tests {
             [("value", BigInt::from(5)), ("res", BigInt::from(5))]
         );
     }
+
+    #[test]
+    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+    fn run_ec_recover_sub_a_b_ok() {
+        let mut vm = vm!();
+        let mut exec_scopes = ExecutionScopes::new();
+
+        vm.run_context.fp = 8;
+        let ids_data = non_continuous_ids_data![("a", -8), ("b", -5)];
+
+        vm.segments = segments![
+            //a
+            ((1, 0), 100),
+            ((1, 1), 0),
+            ((1, 2), 0),
+            //b
+            ((1, 3), 25),
+            ((1, 4), 0),
+            ((1, 5), 0),
+        ];
+
+        assert!(run_hint!(
+            vm,
+            ids_data,
+            hint_code::EC_RECOVER_SUB_A_B,
+            &mut exec_scopes
+        )
+        .is_ok());
+
+        check_scope!(
+            &exec_scopes,
+            [("value", BigInt::from(75)), ("res", BigInt::from(75))]
+        );
+    }
 }

src/hint_processor/builtin_hint_processor/hint_code.rs

@@ -987,5 +987,13 @@ N = pack(ids.n, PRIME)
 x = pack(ids.x, PRIME) % N
 s = pack(ids.s, PRIME) % N
 value = res = div_mod(x, s, N)"#;
+
+pub const EC_RECOVER_SUB_A_B: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import pack
+from starkware.python.math_utils import div_mod, safe_div
+
+a = pack(ids.a, PRIME)
+b = pack(ids.b, PRIME)
+value = res = a - b"#;
+
 #[cfg(feature = "skip_next_instruction_hint")]
 pub const SKIP_NEXT_INSTRUCTION: &str = "skip_next_instruction()";