From ae87c315396e7456fb847f9f739254c4801101d2 Mon Sep 17 00:00:00 2001
From: Pedro Fontana <fontana.pedro93@gmail.com>
Date: Mon, 5 Jun 2023 19:58:50 -0300
Subject: [PATCH] Fix Uint256 unsigned div rem Hints (#1203)

* Fix bug

* Fix U256 inserts

* Add integration test

* Remove dbg

* Update CHANGELOG.md

* Add UINT256_EXPANDED_UNSIGNED_DIV_REM test

* Fix memeory holes
---
 CHANGELOG.md                                           |  2 ++
 cairo_programs/uint256.cairo                           |  8 ++++++++
 cairo_programs/uint256_improvements.cairo              | 10 ++++++++++
 .../builtin_hint_processor/uint256_utils.rs            |  8 ++++----
 src/tests/cairo_run_test.rs                            |  4 ++--
 5 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe809d3269..119cff2e95 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,10 +1,12 @@
 ## Cairo-VM Changelog
 
 #### Upcoming Changes
+* fix: Fix hints `UINT256_UNSIGNED_DIV_REM` && `UINT256_EXPANDED_UNSIGNED_DIV_REM` [#1203](https://github.com/lambdaclass/cairo-rs/pull/1203)
 
 * bugfix: Fix deserialization of scientific notation with fractional values [#1202](https://github.com/lambdaclass/cairo-rs/pull/1202)
 
 * feat: implement `mem_eq` function to test for equality of two ranges in memory [#1198](https://github.com/lambdaclass/cairo-rs/pull/1198)
+
 * perf: use `mem_eq` in `set_add` [#1198](https://github.com/lambdaclass/cairo-rs/pull/1198)
 
 * feat: wrap big variants of `HintError`, `VirtualMachineError`, `RunnerError`, `MemoryError`, `MathError`, `InsufficientAllocatedCellsError` in `Box` [#1193](https://github.com/lambdaclass/cairo-rs/pull/1193)
diff --git a/cairo_programs/uint256.cairo b/cairo_programs/uint256.cairo
index 4a1e6a2e9d..b866b097a9 100644
--- a/cairo_programs/uint256.cairo
+++ b/cairo_programs/uint256.cairo
@@ -58,6 +58,14 @@ func main{range_check_ptr: felt}() {
     assert b_quotient = Uint256(1, 0);
     assert b_remainder = Uint256(340282366920938463463374607431768211377, 0);
 
+    let (c_quotient, c_remainder) = uint256_unsigned_div_rem(
+        Uint256(340282366920938463463374607431768211455, 340282366920938463463374607431768211455),
+        Uint256(1, 0),
+    );
+
+    assert c_quotient = Uint256(340282366920938463463374607431768211455, 340282366920938463463374607431768211455);
+    assert c_remainder = Uint256(0, 0);
+
     let (a_quotient_low, a_quotient_high, a_remainder) = uint256_mul_div_mod(
         Uint256(89, 72),
         Uint256(3, 7),
diff --git a/cairo_programs/uint256_improvements.cairo b/cairo_programs/uint256_improvements.cairo
index bba75d57dc..b21df0ad9b 100644
--- a/cairo_programs/uint256_improvements.cairo
+++ b/cairo_programs/uint256_improvements.cairo
@@ -314,6 +314,16 @@ func test_udiv_expanded{range_check_ptr}() {
     );
     assert b_quotient = Uint256(1, 0);
     assert b_remainder = Uint256(340282366920938463463374607431768211377, 0);
+
+    let (c_div_expanded) = uint256_expand(Uint256(1, 0));
+
+    let (c_quotient, c_remainder) = uint256_unsigned_div_rem_expanded(
+        Uint256(340282366920938463463374607431768211455, 340282366920938463463374607431768211455),
+        c_div_expanded,
+    );
+
+    assert c_quotient = Uint256(340282366920938463463374607431768211455, 340282366920938463463374607431768211455);
+    assert c_remainder = Uint256(0, 0);
     return ();
 }
 
diff --git a/src/hint_processor/builtin_hint_processor/uint256_utils.rs b/src/hint_processor/builtin_hint_processor/uint256_utils.rs
index ad92a1a05d..246c837e9a 100644
--- a/src/hint_processor/builtin_hint_processor/uint256_utils.rs
+++ b/src/hint_processor/builtin_hint_processor/uint256_utils.rs
@@ -376,14 +376,14 @@ pub fn uint256_offseted_unsigned_div_rem(
     //ids.remainder.low = remainder & ((1 << 128) - 1)
     //ids.remainder.high = remainder >> 128
 
-    let a = (a_high << 128_u32) + a_low;
-    let div = (div_high << 128_u32) + div_low;
+    let a = (a_high.to_biguint() << 128_u32) + a_low.to_biguint();
+    let div = (div_high.to_biguint() << 128_u32) + div_low.to_biguint();
     //a and div will always be positive numbers
     //Then, Rust div_rem equals Python divmod
     let (quotient, remainder) = div_rem(a, div);
 
-    let quotient = Uint256::from(quotient);
-    let remainder = Uint256::from(remainder);
+    let quotient = Uint256::from(&quotient);
+    let remainder = Uint256::from(&remainder);
 
     quotient.insert_from_var_name("quotient", vm, ids_data, ap_tracking)?;
     remainder.insert_from_var_name("remainder", vm, ids_data, ap_tracking)?;
diff --git a/src/tests/cairo_run_test.rs b/src/tests/cairo_run_test.rs
index 831dd734a5..6cc0267187 100644
--- a/src/tests/cairo_run_test.rs
+++ b/src/tests/cairo_run_test.rs
@@ -334,7 +334,7 @@ fn dict_update() {
 #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
 fn uint256() {
     let program_data = include_bytes!("../../cairo_programs/uint256.json");
-    run_program_simple_with_memory_holes(program_data.as_slice(), 3514);
+    run_program_simple_with_memory_holes(program_data.as_slice(), 3534);
 }
 
 #[test]
@@ -825,7 +825,7 @@ fn highest_bitlen() {
 #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
 fn uint256_improvements() {
     let program_data = include_bytes!("../../cairo_programs/uint256_improvements.json");
-    run_program_simple_with_memory_holes(program_data.as_slice(), 108);
+    run_program_simple_with_memory_holes(program_data.as_slice(), 128);
 }
 
 #[test]