fix(vrf): use div_mod_unsigned and remove unwrap_or_default (#2262)

* fix(vrf): use div_mod_unsigned and remove unwrap_or_default

* Update CHANGELOG.md

---------

Co-authored-by: Gabriel Bosio <[email protected]>

Author: phrwlk

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 #### Upcoming Changes
 
+* fix: use div_mod_unsigned and remove unwrap_or_default in inv_mod_p_uint256 and uint384_div [#2262](https://github.com/lambdaclass/cairo-vm/pull/2262)
+
 * Refactor: Remove unused error variants [#1760](https://github.com/lambdaclass/cairo-vm/pull/1760/)
 
 * opt(breaking): Avoid cloning constants when compiling hints [#2208](https://github.com/lambdaclass/cairo-vm/pull/2208)

vm/src/hint_processor/builtin_hint_processor/vrf/fq.rs

@@ -6,13 +6,13 @@ use crate::{
         builtin_hint_processor::secp::bigint_utils::Uint512,
         hint_processor_definition::HintReference,
     },
-    math_utils::div_mod,
+    math_utils::div_mod_unsigned,
     serde::deserialize_program::ApTracking,
     stdlib::{collections::HashMap, prelude::*},
     types::errors::math_errors::MathError,
     vm::{errors::hint_errors::HintError, vm_core::VirtualMachine},
 };
-use num_bigint::{BigInt, ToBigInt};
+use num_bigint::BigUint;
 use num_integer::div_rem;
 use num_traits::{One, Zero};
 
@@ -98,19 +98,13 @@ pub fn inv_mod_p_uint256(
     ap_tracking: &ApTracking,
 ) -> Result<(), HintError> {
     // 'a' is not used here or in following hints, so we skip it
-    let b = Uint256::from_var_name("b", vm, ids_data, ap_tracking)?
-        .pack()
-        .to_bigint()
-        .unwrap_or_default();
-    let p = Uint256::from_var_name("p", vm, ids_data, ap_tracking)?
-        .pack()
-        .to_bigint()
-        .unwrap_or_default();
+    let b = Uint256::from_var_name("b", vm, ids_data, ap_tracking)?.pack();
+    let p = Uint256::from_var_name("p", vm, ids_data, ap_tracking)?.pack();
 
     // Main logic:
-    let b_inverse_mod_p = div_mod(&BigInt::one(), &b, &p)?;
+    let b_inverse_mod_p = div_mod_unsigned(&BigUint::one(), &b, &p)?;
 
-    let res = Uint256::from(&b_inverse_mod_p.to_biguint().unwrap_or_default());
+    let res = Uint256::from(&b_inverse_mod_p);
     res.insert_from_var_name("b_inverse_mod_p", vm, ids_data, ap_tracking)
 }