feat(hints): add NewHint#32

CHANGELOG.md

@@ -2,6 +2,14 @@
 
 #### Upcoming Changes
 
+* Add missing hint on cairo_secp lib [#1010](https://github.com/lambdaclass/cairo-rs/pull/1010):
+
+    `BuiltinHintProcessor` now supports the following hint:
+
+    ```python
+        memory[ap] = int(x == 0)
+    ```
+
 * BREAKING CHANGE: refactor `Program` to optimize `Program::clone` [#999](https://github.com/lambdaclass/cairo-rs/pull/999)
     * Breaking change: many fields that were (unnecessarily) public become hidden by the refactor.
 

Cargo.toml

@@ -81,11 +81,13 @@ bitvec = { version = "1", default-features = false, features = ["alloc"] }
 [target.'cfg(target_arch = "wasm32")'.dev-dependencies]
 wasm-bindgen-test = "0.3.34"
 assert_matches = "1.5.0"
+rstest = "0.17.0"
 
 [target.'cfg(not(target_arch = "wasm32"))'.dev-dependencies]
 iai = "0.1"
 rusty-hook = "0.11"
 assert_matches = "1.5.0"
+rstest = "0.17.0"
 criterion = { version = "0.3", features = ["html_reports"] }
 proptest = "1.0.0"
 

cairo_programs/is_zero.cairo

@@ -31,6 +31,34 @@ func is_zero{range_check_ptr}(x: BigInt3) -> (res: felt) {
     return (res=0);
 }
 
+func is_zero_alt{range_check_ptr}(x: BigInt3) -> (res: felt) {
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack
+
+        x = pack(ids.x, PRIME) % SECP_P
+    %}
+    %{ memory[ap] = int(x == 0) %}
+    tempvar x_is_zero;
+
+    if (x_is_zero != 0) {
+        verify_zero(UnreducedBigInt3(d0=x.d0, d1=x.d1, d2=x.d2));
+        return (res=1);
+    }
+
+    %{
+        from starkware.cairo.common.cairo_secp.secp_utils import SECP_P
+        from starkware.python.math_utils import div_mod
+
+        value = x_inv = div_mod(1, x, SECP_P)
+    %}
+    let (x_inv) = nondet_bigint3();
+    let (x_x_inv) = unreduced_mul(x, x_inv);
+
+    // Check that x * x_inv = 1 to verify that x != 0.
+    verify_zero(UnreducedBigInt3(d0=x_x_inv.d0 - 1, d1=x_x_inv.d1, d2=x_x_inv.d2));
+    return (res=0);
+}
+
 func test_is_zero{range_check_ptr}() -> () {
     let zero = BigInt3(0, 0, 0);
 
@@ -52,8 +80,30 @@ func test_is_zero{range_check_ptr}() -> () {
     return ();
 }
 
+func test_is_zero_alt{range_check_ptr}() -> () {
+    let zero = BigInt3(0, 0, 0);
+
+    let (res: felt) = is_zero_alt(zero);
+    assert res = 1;
+
+    let one = BigInt3(1, 0, 0);
+
+    let (res: felt) = is_zero_alt(one);
+    assert res = 0;
+
+    let secp256k1_prime = BigInt3(
+        77371252455336262886226991, 77371252455336267181195263, 19342813113834066795298815
+    );
+
+    let (res: felt) = is_zero_alt(secp256k1_prime);
+    assert res = 1;
+
+    return ();
+}
+
 func main{range_check_ptr}() -> () {
     test_is_zero();
+    test_is_zero_alt();
 
     return ();
 }

src/hint_processor/builtin_hint_processor/builtin_hint_processor_definition.rs

@@ -351,7 +351,7 @@ impl HintProcessor for BuiltinHintProcessor {
             hint_code::IS_ZERO_PACK => {
                 is_zero_pack(vm, exec_scopes, &hint_data.ids_data, &hint_data.ap_tracking)
             }
-            hint_code::IS_ZERO_NONDET => is_zero_nondet(vm, exec_scopes),
+            hint_code::IS_ZERO_NONDET | hint_code::IS_ZERO_INT => is_zero_nondet(vm, exec_scopes),
             hint_code::IS_ZERO_ASSIGN_SCOPE_VARS => is_zero_assign_scope_variables(exec_scopes),
             hint_code::IS_ZERO_ASSIGN_SCOPE_VARS_EXTERNAL_SECP => {
                 is_zero_assign_scope_variables_external_const(exec_scopes)

src/hint_processor/builtin_hint_processor/hint_code.rs

@@ -432,6 +432,7 @@ ids.high = int.from_bytes(hashed[:16], 'big')
 ids.low = int.from_bytes(hashed[16:32], 'big')"#;
 
 pub const IS_ZERO_NONDET: &str = "memory[ap] = to_felt_or_relocatable(x == 0)";
+pub const IS_ZERO_INT: &str = "memory[ap] = int(x == 0)";
 pub const IS_ZERO_PACK: &str = r#"from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack
 
 x = pack(ids.x, PRIME) % SECP_P"#;

src/hint_processor/builtin_hint_processor/secp/field_utils.rs

@@ -202,6 +202,7 @@ mod tests {
     };
     use assert_matches::assert_matches;
 
+    use rstest::rstest;
     #[cfg(target_arch = "wasm32")]
     use wasm_bindgen_test::*;
 
@@ -429,10 +430,11 @@ mod tests {
         );
     }
 
-    #[test]
+    #[rstest]
+    #[case(hint_code::IS_ZERO_NONDET)]
+    #[case(hint_code::IS_ZERO_INT)]
     #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
-    fn run_is_zero_nondet_ok_true() {
-        let hint_code = "memory[ap] = to_felt_or_relocatable(x == 0)";
+    fn run_is_zero_nondet_ok_true(#[case] hint_code: &str) {
         let mut vm = vm_with_range_check!();
 
         //Initialize memory
@@ -456,10 +458,11 @@ mod tests {
         check_memory!(vm.segments.memory, ((1, 15), 1));
     }
 
-    #[test]
+    #[rstest]
+    #[case(hint_code::IS_ZERO_NONDET)]
+    #[case(hint_code::IS_ZERO_INT)]
     #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
-    fn run_is_zero_nondet_ok_false() {
-        let hint_code = "memory[ap] = to_felt_or_relocatable(x == 0)";
+    fn run_is_zero_nondet_ok_false(#[case] hint_code: &str) {
         let mut vm = vm_with_range_check!();
 
         //Initialize memory
@@ -483,10 +486,11 @@ mod tests {
         check_memory!(vm.segments.memory, ((1, 15), 0));
     }
 
-    #[test]
+    #[rstest]
+    #[case(hint_code::IS_ZERO_NONDET)]
+    #[case(hint_code::IS_ZERO_INT)]
     #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
-    fn run_is_zero_nondet_scope_error() {
-        let hint_code = "memory[ap] = to_felt_or_relocatable(x == 0)";
+    fn run_is_zero_nondet_scope_error(#[case] hint_code: &str) {
         let mut vm = vm_with_range_check!();
 
         //Initialize memory
@@ -504,10 +508,11 @@ mod tests {
         );
     }
 
-    #[test]
+    #[rstest]
+    #[case(hint_code::IS_ZERO_NONDET)]
+    #[case(hint_code::IS_ZERO_INT)]
     #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
-    fn run_is_zero_nondet_invalid_memory_insert() {
-        let hint_code = "memory[ap] = to_felt_or_relocatable(x == 0)";
+    fn run_is_zero_nondet_invalid_memory_insert(#[case] hint_code: &str) {
         let mut vm = vm_with_range_check!();
 
         //Insert a value in ap before the hint execution, so the hint memory insert fails
@@ -521,18 +526,17 @@ mod tests {
         exec_scopes.assign_or_update_variable("x", any_box!(BigInt::zero()));
         //Execute the hint
         assert_matches!(
-                    run_hint!(vm, HashMap::new(), hint_code, &mut exec_scopes),
-                    Err(HintError::Memory(
-                        MemoryError::InconsistentMemory(
-                            x,
-                            y,
-                            z
-                        )
-                    )) if x ==
-        vm.run_context.get_ap() &&
-                            y == MaybeRelocatable::from(Felt252::new(55i32)) &&
-                            z == MaybeRelocatable::from(Felt252::new(1i32))
-                );
+            run_hint!(vm, HashMap::new(), hint_code, &mut exec_scopes),
+            Err(HintError::Memory(
+                MemoryError::InconsistentMemory(
+                    x,
+                    y,
+                    z
+                )
+            )) if x == vm.run_context.get_ap()
+                && y == MaybeRelocatable::from(Felt252::new(55i32))
+                && z == MaybeRelocatable::from(Felt252::new(1i32))
+        );
     }
 
     #[test]
@@ -541,6 +545,7 @@ mod tests {
         let mut exec_scopes = ExecutionScopes::new();
         let hint_codes = vec![
             hint_code::IS_ZERO_ASSIGN_SCOPE_VARS,
+            // NOTE: this one requires IS_ZERO_ASSIGN_SCOPE_VARS to execute first.
             hint_code::IS_ZERO_ASSIGN_SCOPE_VARS_EXTERNAL_SECP,
         ];
 
@@ -578,7 +583,7 @@ mod tests {
     #[test]
     #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
     fn is_zero_assign_scope_variables_scope_error() {
-        let hint_code = "from starkware.cairo.common.cairo_secp.secp_utils import SECP_P\nfrom starkware.python.math_utils import div_mod\n\nvalue = x_inv = div_mod(1, x, SECP_P)";
+        let hint_code = hint_code::IS_ZERO_ASSIGN_SCOPE_VARS;
         let mut vm = vm_with_range_check!();
         //Skip `x` assignment
         //Execute the hint