feat(hints): Add alternative hint string for nondet_bigint3 (#1071)

* Add alternative hint string for nondet_bigint_3

* Add integration test

* Rename test file

* Add changelog entry

* Fix hint

* Update CHANGELOG.md

Co-authored-by: Tomás <[email protected]>

---------

Co-authored-by: Mario Rugiero <[email protected]>
Co-authored-by: Tomás <[email protected]>

CHANGELOG.md

@@ -2,6 +2,17 @@
 
 #### Upcoming Changes
 
+* Add alternative hint code for nondet_bigint3 hint [#1071](https://github.com/lambdaclass/cairo-rs/pull/1071)
+
+    `BuiltinHintProcessor` now supports the following hint:
+
+    ```python
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import split
+        segments.write_arg(ids.res.address_, split(value))
+    %}
+    ```
+
 * Add missing hint on vrf.json lib [#1052](https://github.com/lambdaclass/cairo-rs/pull/1052):
 
     `BuiltinHintProcessor` now supports the following hint:
@@ -19,7 +30,7 @@
         value = new_x = (pow(slope, 2, SECP_P) - x0 - x1) % SECP_P
     ```
 
-Add missing hint on vrf.json lib [#1053](https://github.com/lambdaclass/cairo-rs/pull/1053):
+* Add missing hint on vrf.json lib [#1053](https://github.com/lambdaclass/cairo-rs/pull/1053):
 
      `BuiltinHintProcessor` now supports the following hint:
 

cairo_programs/nondet_bigint3_v2.cairo

@@ -0,0 +1,45 @@
+%builtins range_check
+
+from starkware.cairo.common.cairo_secp.bigint import BigInt3, BASE
+
+// Hint arguments: value.
+func nondet_bigint3{range_check_ptr}() -> (res: BigInt3) {
+    // The result should be at the end of the stack after the function returns.
+    let res: BigInt3 = [cast(ap + 5, BigInt3*)];
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import split
+        segments.write_arg(ids.res.address_, split(value))
+    %}
+    // The maximal possible sum of the limbs, assuming each of them is in the range [0, BASE).
+    const MAX_SUM = 3 * (BASE - 1);
+    assert [range_check_ptr] = MAX_SUM - (res.d0 + res.d1 + res.d2);
+
+    // Prepare the result at the end of the stack.
+    tempvar range_check_ptr = range_check_ptr + 4;
+    [range_check_ptr - 3] = res.d0, ap++;
+    [range_check_ptr - 2] = res.d1, ap++;
+    [range_check_ptr - 1] = res.d2, ap++;
+    static_assert &res + BigInt3.SIZE == ap;
+    return (res=res);
+}
+
+func main{range_check_ptr}() {
+    alloc_locals;
+    // Take these hints from div_mod_n just to have a value in scope
+    local a: BigInt3 = BigInt3(1,2,3);
+    local b: BigInt3 = BigInt3(4,5,6);
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import N, pack
+        from starkware.python.math_utils import div_mod, safe_div
+
+        a = pack(ids.a, PRIME)
+        b = pack(ids.b, PRIME)
+        value = res = div_mod(a, b, N)
+    %}
+    let (r) = nondet_bigint3();
+    assert r.d0 = 46511138620617205537268188;
+    assert r.d1 = 26286155657000021849694253;
+    assert r.d2 = 3102515549921694024741409;
+    return();
+}
+

src/hint_processor/builtin_hint_processor/builtin_hint_processor_definition.rs

@@ -297,7 +297,7 @@ impl HintProcessor for BuiltinHintProcessor {
                 &hint_data.ids_data,
                 &hint_data.ap_tracking,
             ),
-            hint_code::NONDET_BIGINT3 => {
+            hint_code::NONDET_BIGINT3_V1 | hint_code::NONDET_BIGINT3_V2 => {
                 nondet_bigint3(vm, exec_scopes, &hint_data.ids_data, &hint_data.ap_tracking)
             }
             hint_code::REDUCE => {

src/hint_processor/builtin_hint_processor/hint_code.rs

@@ -471,10 +471,13 @@ new_state = blake2s_compress(
 
 segments.write_arg(ids.output, new_state)"#;
 
-pub const NONDET_BIGINT3: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import split
+pub const NONDET_BIGINT3_V1: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import split
 
 segments.write_arg(ids.res.address_, split(value))"#;
 
+pub const NONDET_BIGINT3_V2: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import split
+segments.write_arg(ids.res.address_, split(value))"#;
+
 pub const VERIFY_ZERO_V1: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack
 
 q, r = divmod(pack(ids.val, PRIME), SECP_P)

src/tests/cairo_run_test.rs

@@ -904,3 +904,10 @@ fn ec_double_assign_new_x_v3() {
     let program_data = include_bytes!("../../cairo_programs/ec_double_assign_new_x_v3.json");
     run_program_simple(program_data.as_slice());
 }
+
+#[test]
+#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+fn nondet_bigint3_v2() {
+    let program_data = include_bytes!("../../cairo_programs/nondet_bigint3_v2.json");
+    run_program_simple(program_data.as_slice());
+}