Implement Hint#48 pack512 (lambdaclass#1000)

* Add cairo program for integration test

* WIP implement hint

* Add pack_512 fn + unit tests

* Update pack_512.cairo

* Add hint code && implement hint

* Reimplement pack_512 function && fix hint

* handle error

* Fix merge conflicts

* Update Changelog

* Rename pack_512.rs -> inv_mod_p_uint512.rs

* Add integration test

* Rename u255.cairo -> cairo_programs/fq_uint256.cairo

* pack_512 -> BigUint

* Add unit test

* fix wasm tests

* Remove fq_uint256.cairo

* use u128::MAX

* fix tests

---------

Co-authored-by: Pedro Fontana <pedro.fontana@lamdaclass.com>

CHANGELOG.md

@@ -2,6 +2,25 @@
 
 #### Upcoming Changes
 
+* Add missing hint on vrf.json lib [#1000](https://github.com/lambdaclass/cairo-rs/pull/1000):
+
+    `BuiltinHintProcessor` now supports the following hint:
+
+    ```python
+        def pack_512(u, num_bits_shift: int) -> int:
+            limbs = (u.d0, u.d1, u.d2, u.d3)
+            return sum(limb << (num_bits_shift * i) for i, limb in enumerate(limbs))
+
+        x = pack_512(ids.x, num_bits_shift = 128)
+        p = ids.p.low + (ids.p.high << 128)
+        x_inverse_mod_p = pow(x,-1, p) 
+
+        x_inverse_mod_p_split = (x_inverse_mod_p & ((1 << 128) - 1), x_inverse_mod_p >> 128)
+
+        ids.x_inverse_mod_p.low = x_inverse_mod_p_split[0]
+        ids.x_inverse_mod_p.high = x_inverse_mod_p_split[1]
+    ```
+
 * BREAKING CHANGE: Fix `CairoRunner::get_memory_holes` [#1027](https://github.com/lambdaclass/cairo-rs/pull/1027):
 
   * Skip builtin segements when counting memory holes

cairo_programs/inv_mod_p_uint512.cairo

@@ -0,0 +1,43 @@
+%builtins range_check
+
+from starkware.cairo.common.uint256 import Uint256
+
+const P_low = 201385395114098847380338600778089168199;
+const P_high = 64323764613183177041862057485226039389;
+
+struct Uint512 {
+    d0: felt,
+    d1: felt,
+    d2: felt,
+    d3: felt,
+}
+
+func inv_mod_p_uint512{range_check_ptr}(x: Uint512) -> Uint256 {
+    alloc_locals;
+    local x_inverse_mod_p: Uint256;
+    local p: Uint256 = Uint256(P_low, P_high);
+    // To whitelist
+    %{
+        def pack_512(u, num_bits_shift: int) -> int:
+            limbs = (u.d0, u.d1, u.d2, u.d3)
+            return sum(limb << (num_bits_shift * i) for i, limb in enumerate(limbs))
+
+        x = pack_512(ids.x, num_bits_shift = 128)
+        p = ids.p.low + (ids.p.high << 128)
+        x_inverse_mod_p = pow(x,-1, p) 
+
+        x_inverse_mod_p_split = (x_inverse_mod_p & ((1 << 128) - 1), x_inverse_mod_p >> 128)
+
+        ids.x_inverse_mod_p.low = x_inverse_mod_p_split[0]
+        ids.x_inverse_mod_p.high = x_inverse_mod_p_split[1]
+    %}
+
+    return x_inverse_mod_p;
+}
+
+func main{range_check_ptr: felt}() {
+    let x = Uint512(101, 2, 15, 61);
+    let y = inv_mod_p_uint512(x);
+    assert y = Uint256(80275402838848031859800366538378848249, 5810892639608724280512701676461676039);
+    return ();
+}

src/hint_processor/builtin_hint_processor/builtin_hint_processor_definition.rs

@@ -84,6 +84,8 @@ use felt::Felt252;
 #[cfg(feature = "skip_next_instruction_hint")]
 use crate::hint_processor::builtin_hint_processor::skip_next_instruction::skip_next_instruction;
 
+use super::vrf::inv_mod_p_uint512::inv_mod_p_uint512;
+
 pub struct HintProcessorData {
     pub code: String,
     pub ap_tracking: ApTracking,
@@ -567,6 +569,9 @@ impl HintProcessor for BuiltinHintProcessor {
                 hi_max_bitlen(vm, &hint_data.ids_data, &hint_data.ap_tracking)
             }
             hint_code::QUAD_BIT => quad_bit(vm, &hint_data.ids_data, &hint_data.ap_tracking),
+            hint_code::INV_MOD_P_UINT512 => {
+                inv_mod_p_uint512(vm, &hint_data.ids_data, &hint_data.ap_tracking)
+            }
             hint_code::DI_BIT => di_bit(vm, &hint_data.ids_data, &hint_data.ap_tracking),
             #[cfg(feature = "skip_next_instruction_hint")]
             hint_code::SKIP_NEXT_INSTRUCTION => skip_next_instruction(vm),

src/hint_processor/builtin_hint_processor/hint_code.rs

@@ -924,6 +924,19 @@ pub const QUAD_BIT: &str = r#"ids.quad_bit = (
     + ((ids.scalar_u >> (ids.m - 1)) & 1)
 )"#;
 
+pub const INV_MOD_P_UINT512: &str = "def pack_512(u, num_bits_shift: int) -> int:
+    limbs = (u.d0, u.d1, u.d2, u.d3)
+    return sum(limb << (num_bits_shift * i) for i, limb in enumerate(limbs))
+
+x = pack_512(ids.x, num_bits_shift = 128)
+p = ids.p.low + (ids.p.high << 128)
+x_inverse_mod_p = pow(x,-1, p) 
+
+x_inverse_mod_p_split = (x_inverse_mod_p & ((1 << 128) - 1), x_inverse_mod_p >> 128)
+
+ids.x_inverse_mod_p.low = x_inverse_mod_p_split[0]
+ids.x_inverse_mod_p.high = x_inverse_mod_p_split[1]";
+
 pub const DI_BIT: &str =
     r#"ids.dibit = ((ids.scalar_u >> ids.m) & 1) + 2 * ((ids.scalar_v >> ids.m) & 1)"#;
 

src/hint_processor/builtin_hint_processor/mod.rs

@@ -29,3 +29,4 @@ pub mod uint256_utils;
 pub mod uint384;
 pub mod uint384_extension;
 pub mod usort;
+pub mod vrf;

src/hint_processor/builtin_hint_processor/vrf/inv_mod_p_uint512.rs

@@ -0,0 +1,212 @@
+use core::ops::Shl;
+
+use crate::stdlib::prelude::String;
+use crate::stdlib::vec::Vec;
+use crate::{
+    hint_processor::{
+        builtin_hint_processor::hint_utils::get_relocatable_from_var_name,
+        hint_processor_definition::HintReference,
+    },
+    math_utils::div_mod,
+    serde::deserialize_program::ApTracking,
+    stdlib::collections::HashMap,
+    vm::errors::hint_errors::HintError,
+};
+use felt::Felt252;
+use num_bigint::{BigInt, BigUint};
+use num_traits::One;
+
+use crate::vm::vm_core::VirtualMachine;
+
+/*
+def pack_512(d0, d1,d2,d3, num_bits_shift: int) -> int:
+    limbs = (d0, d1, d2, d3)
+    return sum(limb << (num_bits_shift * i) for i, limb in enumerate(limbs))
+
+*/
+fn pack_512(limbs: &[Felt252; 4], num_bits_shift: usize) -> BigUint {
+    limbs
+        .iter()
+        .enumerate()
+        .map(|(idx, value)| value.to_biguint().shl(idx * num_bits_shift))
+        .sum()
+}
+
+/*
+Implements hint:
+%{
+    def pack_512(u, num_bits_shift: int) -> int:
+        limbs = (u.d0, u.d1, u.d2, u.d3)
+        return sum(limb << (num_bits_shift * i) for i, limb in enumerate(limbs))
+
+    x = pack_512(ids.x, num_bits_shift = 128)
+    p = ids.p.low + (ids.p.high << 128)
+    x_inverse_mod_p = pow(x,-1, p)
+
+    x_inverse_mod_p_split = (x_inverse_mod_p & ((1 << 128) - 1), x_inverse_mod_p >> 128)
+
+    ids.x_inverse_mod_p.low = x_inverse_mod_p_split[0]
+    ids.x_inverse_mod_p.high = x_inverse_mod_p_split[1]
+%}
+*/
+pub fn inv_mod_p_uint512(
+    vm: &mut VirtualMachine,
+    ids_data: &HashMap<String, HintReference>,
+    ap_tracking: &ApTracking,
+) -> Result<(), HintError> {
+    let limbs_ptr = get_relocatable_from_var_name("x", vm, ids_data, ap_tracking)?;
+    let limbs: Vec<Felt252> = vm
+        .get_integer_range(limbs_ptr, 4)?
+        .iter()
+        .map(|f| f.clone().into_owned())
+        .collect();
+
+    let x = pack_512(
+        &limbs
+            .try_into()
+            .map_err(|_| HintError::FixedSizeArrayFail(4))?,
+        128,
+    );
+
+    let p_ptr = get_relocatable_from_var_name("p", vm, ids_data, ap_tracking)?;
+    let p_low = vm.get_integer(p_ptr)?;
+    let p_high = vm.get_integer((p_ptr + 1_i32)?)?;
+
+    let p = p_low.into_owned().to_biguint() + (p_high.into_owned().to_biguint() << 128_usize);
+    let x_inverse_mod_p =
+        Felt252::from(div_mod(&BigInt::one(), &BigInt::from(x), &BigInt::from(p)));
+
+    let x_inverse_mod_p_ptr =
+        get_relocatable_from_var_name("x_inverse_mod_p", vm, ids_data, ap_tracking)?;
+
+    vm.insert_value(
+        x_inverse_mod_p_ptr,
+        &x_inverse_mod_p & &Felt252::from(u128::MAX),
+    )?;
+
+    vm.insert_value((x_inverse_mod_p_ptr + 1_i32)?, x_inverse_mod_p >> 128)?;
+
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::any_box;
+    use crate::hint_processor::builtin_hint_processor::builtin_hint_processor_definition::BuiltinHintProcessor;
+    use crate::hint_processor::builtin_hint_processor::builtin_hint_processor_definition::HintProcessorData;
+    use crate::hint_processor::hint_processor_definition::HintProcessor;
+    use crate::types::relocatable::{MaybeRelocatable, Relocatable};
+    use crate::utils::test_utils::mayberelocatable;
+    use crate::utils::test_utils::memory;
+    use crate::utils::test_utils::memory_from_memory;
+    use crate::utils::test_utils::memory_inner;
+    use crate::vm::errors::memory_errors::MemoryError;
+    use crate::vm::runners::builtin_runner::RangeCheckBuiltinRunner;
+    use crate::vm::vm_memory::memory::Memory;
+    use crate::vm::vm_memory::memory_segments::MemorySegmentManager;
+    use crate::{
+        hint_processor::builtin_hint_processor::hint_code::INV_MOD_P_UINT512,
+        types::exec_scope::ExecutionScopes,
+        utils::test_utils::{
+            add_segments, non_continuous_ids_data, run_hint, segments, vm_with_range_check,
+        },
+    };
+    use num_traits::{FromPrimitive, Num};
+    #[cfg(target_arch = "wasm32")]
+    use wasm_bindgen_test::*;
+
+    #[test]
+    fn test_pack_512() {
+        assert_eq!(
+            pack_512(
+                &[
+                    Felt252::new(13123),
+                    Felt252::new(534354),
+                    Felt252::new(9901823),
+                    Felt252::new(7812371)
+                ],
+                2
+            ),
+            BigUint::from(660571451_u128)
+        );
+        assert_eq!(
+            pack_512(
+                &[
+                    Felt252::new(13123),
+                    Felt252::new(534354),
+                    Felt252::new(9901823),
+                    Felt252::new(7812371)
+                ],
+                76
+            ),
+            BigUint::from_str_radix(
+                "3369937688063908975412897222574435556910082026593269572342866796946053411651",
+                10
+            )
+            .unwrap()
+        );
+
+        assert_eq!(
+            pack_512(
+                &[
+                    Felt252::new(90812398),
+                    Felt252::new(55),
+                    Felt252::new(83127),
+                    Felt252::from_i128(45312309123).unwrap()
+                ],
+                761
+            ),
+            BigUint::from_str_radix("80853029148137605102740201774483901385926652025450340798711030404174727480763870493377667725625759764292622444803788021444434452626041518098606806141685367065099387655302625873713592439838446220691925786159227082298892378981461987274693629088875674987359669209043388107114325450518636532594445145924759095125734364345163525655691027843325303271775064263282011908012871334532482494107608759994020937000541268185418760956243245766874157401648637158526410360988956699864519559367805347900540475245570833510432301935056255005826223734865268553682118180231081037207280009003811438596531432027766301678781550463988061852846171462460595592799020846810683500364584025173048032553173114469560143047387885550", 10).unwrap()
+        );
+    }
+
+    #[test]
+    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+    fn run_inv_mod_p_uint512_ok() {
+        let mut vm = vm_with_range_check!();
+        add_segments!(vm, 3);
+
+        //Initialize fp
+        vm.run_context.fp = 25;
+
+        //Create hint data
+        let ids_data = non_continuous_ids_data![("x", -5), ("p", -10), ("x_inverse_mod_p", -20)];
+        vm.segments = segments![
+            ((1, 20), 101), //ids.x.d0
+            ((1, 21), 2),   // ids.x.d1
+            ((1, 22), 15),  // ids.x.d2
+            ((1, 23), 61)   // ids.x.d3
+                            // ((1, 15), 201385395114098847380338600778089168199),   // ids.p.low
+                            // ((1, 16), 64323764613183177041862057485226039389)   // ids.p.high
+        ];
+        vm.insert_value(
+            Relocatable::from((1, 15)),
+            Felt252::from_str_radix("201385395114098847380338600778089168199", 10).unwrap(),
+        )
+        .expect("error setting ids.p");
+        vm.insert_value(
+            Relocatable::from((1, 16)),
+            Felt252::from_str_radix("64323764613183177041862057485226039389", 10).unwrap(),
+        )
+        .expect("error setting ids.p");
+
+        let mut exec_scopes = ExecutionScopes::new();
+        //Execute the hint
+        assert!(run_hint!(vm, ids_data, INV_MOD_P_UINT512, &mut exec_scopes).is_ok());
+
+        // Check VM inserts
+        assert_eq!(
+            vm.get_integer(Relocatable::from((1, 5)))
+                .unwrap()
+                .into_owned(),
+            Felt252::from_str_radix("80275402838848031859800366538378848249", 10).unwrap()
+        );
+        assert_eq!(
+            vm.get_integer(Relocatable::from((1, 6)))
+                .unwrap()
+                .into_owned(),
+            Felt252::from_str_radix("5810892639608724280512701676461676039", 10).unwrap()
+        );
+    }
+}

src/hint_processor/builtin_hint_processor/vrf/mod.rs

@@ -0,0 +1 @@
+pub mod inv_mod_p_uint512;

src/tests/cairo_run_test.rs

@@ -798,3 +798,10 @@ fn memory_holes() {
     let program_data = include_bytes!("../../cairo_programs/memory_holes.json");
     run_program_simple_with_memory_holes(program_data.as_slice(), 5)
 }
+
+#[test]
+#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+fn cairo_run_inv_mod_p_uint512() {
+    let program_data = include_bytes!("../../cairo_programs/inv_mod_p_uint512.json");
+    run_program_simple(program_data.as_slice());
+}