chore: Sync to noir-lang/noir

chore: uses sha256compression opcode in Noir and implements acvm solver for it (AztecProtocol/aztec-packages#4511) chore!: move noir out of yarn-project (AztecProtocol/aztec-packages#4479) feat!: note type ids (AztecProtocol/aztec-packages#4500) chore: Pull noir (AztecProtocol/aztec-packages#4546) feat: Added cast opcode and cast calldata (AztecProtocol/aztec-packages#4423) refactor: cleanup of `abi.nr` in `aztec-nr` (AztecProtocol/aztec-packages#4473)
noir-lang · Feb 13, 2024 · cf7b00e · cf7b00e
1 parent 6ff518a
commit cf7b00e
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Showing 24 changed files with 386 additions and 197 deletions.
diff --git a/acvm-repo/acir/codegen/acir.cpp b/acvm-repo/acir/codegen/acir.cpp
@@ -468,6 +468,16 @@ namespace Circuit {
             static BinaryIntOp bincodeDeserialize(std::vector<uint8_t>);
         };
 
+        struct Cast {
+            Circuit::MemoryAddress destination;
+            Circuit::MemoryAddress source;
+            uint32_t bit_size;
+
+            friend bool operator==(const Cast&, const Cast&);
+            std::vector<uint8_t> bincodeSerialize() const;
+            static Cast bincodeDeserialize(std::vector<uint8_t>);
+        };
+
         struct JumpIfNot {
             Circuit::MemoryAddress condition;
             uint64_t location;
@@ -590,7 +600,7 @@ namespace Circuit {
             static Stop bincodeDeserialize(std::vector<uint8_t>);
         };
 
-        std::variant<BinaryFieldOp, BinaryIntOp, JumpIfNot, JumpIf, Jump, CalldataCopy, Call, Const, Return, ForeignCall, Mov, Load, Store, BlackBox, Trap, Stop> value;
+        std::variant<BinaryFieldOp, BinaryIntOp, Cast, JumpIfNot, JumpIf, Jump, CalldataCopy, Call, Const, Return, ForeignCall, Mov, Load, Store, BlackBox, Trap, Stop> value;
 
         friend bool operator==(const BrilligOpcode&, const BrilligOpcode&);
         std::vector<uint8_t> bincodeSerialize() const;
@@ -4300,6 +4310,50 @@ Circuit::BrilligOpcode::BinaryIntOp serde::Deserializable<Circuit::BrilligOpcode
     return obj;
 }
 
+namespace Circuit {
+
+    inline bool operator==(const BrilligOpcode::Cast &lhs, const BrilligOpcode::Cast &rhs) {
+        if (!(lhs.destination == rhs.destination)) { return false; }
+        if (!(lhs.source == rhs.source)) { return false; }
+        if (!(lhs.bit_size == rhs.bit_size)) { return false; }
+        return true;
+    }
+
+    inline std::vector<uint8_t> BrilligOpcode::Cast::bincodeSerialize() const {
+        auto serializer = serde::BincodeSerializer();
+        serde::Serializable<BrilligOpcode::Cast>::serialize(*this, serializer);
+        return std::move(serializer).bytes();
+    }
+
+    inline BrilligOpcode::Cast BrilligOpcode::Cast::bincodeDeserialize(std::vector<uint8_t> input) {
+        auto deserializer = serde::BincodeDeserializer(input);
+        auto value = serde::Deserializable<BrilligOpcode::Cast>::deserialize(deserializer);
+        if (deserializer.get_buffer_offset() < input.size()) {
+            throw serde::deserialization_error("Some input bytes were not read");
+        }
+        return value;
+    }
+
+} // end of namespace Circuit
+
+template <>
+template <typename Serializer>
+void serde::Serializable<Circuit::BrilligOpcode::Cast>::serialize(const Circuit::BrilligOpcode::Cast &obj, Serializer &serializer) {
+    serde::Serializable<decltype(obj.destination)>::serialize(obj.destination, serializer);
+    serde::Serializable<decltype(obj.source)>::serialize(obj.source, serializer);
+    serde::Serializable<decltype(obj.bit_size)>::serialize(obj.bit_size, serializer);
+}
+
+template <>
+template <typename Deserializer>
+Circuit::BrilligOpcode::Cast serde::Deserializable<Circuit::BrilligOpcode::Cast>::deserialize(Deserializer &deserializer) {
+    Circuit::BrilligOpcode::Cast obj;
+    obj.destination = serde::Deserializable<decltype(obj.destination)>::deserialize(deserializer);
+    obj.source = serde::Deserializable<decltype(obj.source)>::deserialize(deserializer);
+    obj.bit_size = serde::Deserializable<decltype(obj.bit_size)>::deserialize(deserializer);
+    return obj;
+}
+
 namespace Circuit {
 
     inline bool operator==(const BrilligOpcode::JumpIfNot &lhs, const BrilligOpcode::JumpIfNot &rhs) {

diff --git a/acvm-repo/acir/tests/test_program_serialization.rs b/acvm-repo/acir/tests/test_program_serialization.rs
@@ -206,11 +206,11 @@ fn simple_brillig_foreign_call() {
     let bytes = Circuit::serialize_circuit(&circuit);
 
     let expected_serialization: Vec<u8> = vec![
-        31, 139, 8, 0, 0, 0, 0, 0, 0, 255, 173, 143, 65, 10, 192, 32, 12, 4, 215, 148, 150, 246,
-        212, 175, 216, 31, 244, 51, 61, 244, 226, 65, 196, 247, 171, 24, 33, 136, 122, 209, 129,
-        144, 176, 132, 101, 247, 4, 160, 144, 217, 196, 45, 41, 218, 203, 91, 207, 241, 168, 117,
-        94, 90, 230, 37, 238, 144, 216, 27, 249, 11, 87, 156, 131, 239, 223, 248, 207, 186, 81,
-        235, 150, 67, 173, 221, 189, 95, 18, 34, 97, 64, 0, 116, 135, 40, 214, 136, 1, 0, 0,
+        31, 139, 8, 0, 0, 0, 0, 0, 0, 255, 173, 143, 177, 10, 192, 32, 16, 67, 227, 21, 74, 233,
+        212, 79, 177, 127, 208, 159, 233, 224, 226, 32, 226, 247, 139, 168, 16, 68, 93, 244, 45,
+        119, 228, 142, 144, 92, 0, 20, 50, 7, 237, 76, 213, 190, 50, 245, 26, 175, 218, 231, 165,
+        57, 175, 148, 14, 137, 179, 147, 191, 114, 211, 221, 216, 240, 59, 63, 107, 221, 115, 104,
+        181, 103, 244, 43, 36, 10, 38, 68, 108, 25, 253, 238, 136, 1, 0, 0,
     ];
 
     assert_eq!(bytes, expected_serialization)
@@ -305,15 +305,15 @@ fn complex_brillig_foreign_call() {
     let bytes = Circuit::serialize_circuit(&circuit);
 
     let expected_serialization: Vec<u8> = vec![
-        31, 139, 8, 0, 0, 0, 0, 0, 0, 255, 213, 84, 73, 14, 131, 48, 12, 28, 147, 166, 165, 167,
-        126, 161, 82, 251, 128, 180, 47, 224, 47, 85, 111, 32, 56, 242, 124, 130, 24, 68, 176, 2,
-        23, 130, 4, 35, 89, 206, 50, 137, 71, 182, 147, 28, 128, 96, 128, 241, 150, 113, 44, 156,
-        135, 24, 121, 5, 189, 219, 134, 143, 164, 187, 203, 237, 165, 49, 59, 129, 70, 179, 131,
-        198, 177, 31, 14, 90, 239, 148, 117, 73, 154, 63, 19, 121, 63, 23, 111, 214, 219, 149, 243,
-        27, 125, 206, 117, 208, 63, 85, 222, 161, 248, 32, 167, 72, 162, 245, 235, 44, 166, 94, 20,
-        21, 251, 30, 196, 253, 213, 85, 83, 254, 91, 163, 168, 90, 234, 43, 24, 191, 213, 190, 172,
-        156, 235, 17, 126, 59, 49, 142, 68, 120, 75, 220, 7, 166, 84, 90, 68, 72, 194, 139, 180,
-        136, 25, 58, 46, 103, 45, 188, 25, 5, 0, 0,
+        31, 139, 8, 0, 0, 0, 0, 0, 0, 255, 213, 84, 75, 10, 132, 48, 12, 125, 177, 163, 35, 179,
+        154, 35, 8, 51, 7, 232, 204, 9, 188, 139, 184, 83, 116, 233, 241, 173, 152, 98, 12, 213,
+        141, 21, 244, 65, 232, 39, 175, 233, 35, 73, 155, 3, 32, 204, 48, 206, 18, 158, 19, 175,
+        37, 60, 175, 228, 209, 30, 195, 143, 226, 197, 178, 103, 105, 76, 110, 160, 209, 156, 160,
+        209, 247, 195, 69, 235, 29, 179, 46, 81, 243, 103, 2, 239, 231, 225, 44, 117, 150, 241,
+        250, 201, 99, 206, 251, 96, 95, 161, 242, 14, 193, 243, 40, 162, 105, 253, 219, 12, 75, 47,
+        146, 186, 251, 37, 116, 86, 93, 219, 55, 245, 96, 20, 85, 75, 253, 136, 249, 87, 249, 105,
+        231, 220, 4, 249, 237, 132, 56, 20, 224, 109, 113, 223, 88, 82, 153, 34, 64, 34, 14, 164,
+        69, 172, 48, 2, 23, 243, 6, 31, 25, 5, 0, 0,
     ];
 
     assert_eq!(bytes, expected_serialization)

diff --git a/acvm-repo/acvm/src/pwg/blackbox/hash.rs b/acvm-repo/acvm/src/pwg/blackbox/hash.rs
@@ -3,7 +3,7 @@ use acir::{
     native_types::{Witness, WitnessMap},
     BlackBoxFunc, FieldElement,
 };
-use acvm_blackbox_solver::BlackBoxResolutionError;
+use acvm_blackbox_solver::{sha256compression, BlackBoxResolutionError};
 
 use crate::pwg::{insert_value, witness_to_value};
 use crate::OpcodeResolutionError;
@@ -86,3 +86,48 @@ fn write_digest_to_outputs(
 
     Ok(())
 }
+
+pub(crate) fn solve_sha_256_permutation_opcode(
+    initial_witness: &mut WitnessMap,
+    inputs: &[FunctionInput],
+    hash_values: &[FunctionInput],
+    outputs: &[Witness],
+    black_box_func: BlackBoxFunc,
+) -> Result<(), OpcodeResolutionError> {
+    let mut message = [0; 16];
+    if inputs.len() != 16 {
+        return Err(OpcodeResolutionError::BlackBoxFunctionFailed(
+            black_box_func,
+            format!("Expected 16 inputs but encountered {}", &message.len()),
+        ));
+    }
+    for (i, input) in inputs.iter().enumerate() {
+        let value = witness_to_value(initial_witness, input.witness)?;
+        message[i] = value.to_u128() as u32;
+    }
+
+    if hash_values.len() != 8 {
+        return Err(OpcodeResolutionError::BlackBoxFunctionFailed(
+            black_box_func,
+            format!("Expected 8 values but encountered {}", hash_values.len()),
+        ));
+    }
+    let mut state = [0; 8];
+    for (i, hash) in hash_values.iter().enumerate() {
+        let value = witness_to_value(initial_witness, hash.witness)?;
+        state[i] = value.to_u128() as u32;
+    }
+
+    sha256compression(&mut state, &message);
+    let outputs: [Witness; 8] = outputs.try_into().map_err(|_| {
+        OpcodeResolutionError::BlackBoxFunctionFailed(
+            black_box_func,
+            format!("Expected 8 outputs but encountered {}", outputs.len()),
+        )
+    })?;
+    for (output_witness, value) in outputs.iter().zip(state.into_iter()) {
+        insert_value(output_witness, FieldElement::from(value as u128), initial_witness)?;
+    }
+
+    Ok(())
+}
diff --git a/acvm-repo/acvm/src/pwg/blackbox/mod.rs b/acvm-repo/acvm/src/pwg/blackbox/mod.rs
@@ -20,7 +20,7 @@ mod signature;
 
 use fixed_base_scalar_mul::{embedded_curve_add, fixed_base_scalar_mul};
 // Hash functions should eventually be exposed for external consumers.
-use hash::solve_generic_256_hash_opcode;
+use hash::{solve_generic_256_hash_opcode, solve_sha_256_permutation_opcode};
 use logic::{and, xor};
 use pedersen::pedersen;
 use range::solve_range_opcode;
@@ -205,6 +205,14 @@ pub(crate) fn solve(
             bigint_solver.bigint_to_bytes(*input, outputs, initial_witness)
         }
         BlackBoxFuncCall::Poseidon2Permutation { .. } => todo!(),
-        BlackBoxFuncCall::Sha256Compression { .. } => todo!(),
+        BlackBoxFuncCall::Sha256Compression { inputs, hash_values, outputs } => {
+            solve_sha_256_permutation_opcode(
+                initial_witness,
+                inputs,
+                hash_values,
+                outputs,
+                bb_func.get_black_box_func(),
+            )
+        }
     }
 }
diff --git a/acvm-repo/acvm_js/test/shared/complex_foreign_call.ts b/acvm-repo/acvm_js/test/shared/complex_foreign_call.ts
@@ -2,13 +2,13 @@ import { WitnessMap } from '@noir-lang/acvm_js';
 
 // See `complex_brillig_foreign_call` integration test in `acir/tests/test_program_serialization.rs`.
 export const bytecode = Uint8Array.from([
-  31, 139, 8, 0, 0, 0, 0, 0, 0, 255, 213, 84, 73, 14, 131, 48, 12, 28, 147, 166, 165, 167, 126, 161, 82, 251, 128, 180,
-  47, 224, 47, 85, 111, 32, 56, 242, 124, 130, 24, 68, 176, 2, 23, 130, 4, 35, 89, 206, 50, 137, 71, 182, 147, 28, 128,
-  96, 128, 241, 150, 113, 44, 156, 135, 24, 121, 5, 189, 219, 134, 143, 164, 187, 203, 237, 165, 49, 59, 129, 70, 179,
-  131, 198, 177, 31, 14, 90, 239, 148, 117, 73, 154, 63, 19, 121, 63, 23, 111, 214, 219, 149, 243, 27, 125, 206, 117,
-  208, 63, 85, 222, 161, 248, 32, 167, 72, 162, 245, 235, 44, 166, 94, 20, 21, 251, 30, 196, 253, 213, 85, 83, 254, 91,
-  163, 168, 90, 234, 43, 24, 191, 213, 190, 172, 156, 235, 17, 126, 59, 49, 142, 68, 120, 75, 220, 7, 166, 84, 90, 68,
-  72, 194, 139, 180, 136, 25, 58, 46, 103, 45, 188, 25, 5, 0, 0,
+  31, 139, 8, 0, 0, 0, 0, 0, 0, 255, 213, 84, 75, 10, 132, 48, 12, 125, 177, 163, 35, 179, 154, 35, 8, 51, 7, 232, 204,
+  9, 188, 139, 184, 83, 116, 233, 241, 173, 152, 98, 12, 213, 141, 21, 244, 65, 232, 39, 175, 233, 35, 73, 155, 3, 32,
+  204, 48, 206, 18, 158, 19, 175, 37, 60, 175, 228, 209, 30, 195, 143, 226, 197, 178, 103, 105, 76, 110, 160, 209, 156,
+  160, 209, 247, 195, 69, 235, 29, 179, 46, 81, 243, 103, 2, 239, 231, 225, 44, 117, 150, 241, 250, 201, 99, 206, 251,
+  96, 95, 161, 242, 14, 193, 243, 40, 162, 105, 253, 219, 12, 75, 47, 146, 186, 251, 37, 116, 86, 93, 219, 55, 245, 96,
+  20, 85, 75, 253, 136, 249, 87, 249, 105, 231, 220, 4, 249, 237, 132, 56, 20, 224, 109, 113, 223, 88, 82, 153, 34, 64,
+  34, 14, 164, 69, 172, 48, 2, 23, 243, 6, 31, 25, 5, 0, 0,
 ]);
 export const initialWitnessMap: WitnessMap = new Map([
   [1, '0x0000000000000000000000000000000000000000000000000000000000000001'],

diff --git a/acvm-repo/acvm_js/test/shared/foreign_call.ts b/acvm-repo/acvm_js/test/shared/foreign_call.ts
@@ -2,10 +2,10 @@ import { WitnessMap } from '@noir-lang/acvm_js';
 
 // See `simple_brillig_foreign_call` integration test in `acir/tests/test_program_serialization.rs`.
 export const bytecode = Uint8Array.from([
-  31, 139, 8, 0, 0, 0, 0, 0, 0, 255, 173, 143, 65, 10, 192, 32, 12, 4, 215, 148, 150, 246, 212, 175, 216, 31, 244, 51,
-  61, 244, 226, 65, 196, 247, 171, 24, 33, 136, 122, 209, 129, 144, 176, 132, 101, 247, 4, 160, 144, 217, 196, 45, 41,
-  218, 203, 91, 207, 241, 168, 117, 94, 90, 230, 37, 238, 144, 216, 27, 249, 11, 87, 156, 131, 239, 223, 248, 207, 186,
-  81, 235, 150, 67, 173, 221, 189, 95, 18, 34, 97, 64, 0, 116, 135, 40, 214, 136, 1, 0, 0,
+  31, 139, 8, 0, 0, 0, 0, 0, 0, 255, 173, 143, 177, 10, 192, 32, 16, 67, 227, 21, 74, 233, 212, 79, 177, 127, 208, 159,
+  233, 224, 226, 32, 226, 247, 139, 168, 16, 68, 93, 244, 45, 119, 228, 142, 144, 92, 0, 20, 50, 7, 237, 76, 213, 190,
+  50, 245, 26, 175, 218, 231, 165, 57, 175, 148, 14, 137, 179, 147, 191, 114, 211, 221, 216, 240, 59, 63, 107, 221, 115,
+  104, 181, 103, 244, 43, 36, 10, 38, 68, 108, 25, 253, 238, 136, 1, 0, 0,
 ]);
 export const initialWitnessMap: WitnessMap = new Map([
   [1, '0x0000000000000000000000000000000000000000000000000000000000000005'],

diff --git a/acvm-repo/blackbox_solver/Cargo.toml b/acvm-repo/blackbox_solver/Cargo.toml
@@ -18,7 +18,7 @@ thiserror.workspace = true
 
 blake2 = "0.10.6"
 blake3 = "1.5.0"
-sha2 = "0.10.6"
+sha2 = { version="0.10.6", features = ["compress",] }
 sha3 = "0.10.6"
 keccak = "0.1.4"
 k256 = { version = "0.11.0", features = [

diff --git a/acvm-repo/blackbox_solver/src/lib.rs b/acvm-repo/blackbox_solver/src/lib.rs
@@ -43,6 +43,16 @@ pub fn keccak256(inputs: &[u8]) -> Result<[u8; 32], BlackBoxResolutionError> {
         .map_err(|err| BlackBoxResolutionError::Failed(BlackBoxFunc::Keccak256, err))
 }
 
+pub fn sha256compression(state: &mut [u32; 8], msg_blocks: &[u32; 16]) {
+    let mut blocks = [0_u8; 64];
+    for (i, block) in msg_blocks.iter().enumerate() {
+        let bytes = block.to_be_bytes();
+        blocks[i * 4..i * 4 + 4].copy_from_slice(&bytes);
+    }
+    let blocks: GenericArray<u8, sha2::digest::typenum::U64> = blocks.into();
+    sha2::compress256(state, &[blocks]);
+}
+
 const KECCAK_LANES: usize = 25;
 
 pub fn keccakf1600(

diff --git a/acvm-repo/brillig/src/opcodes.rs b/acvm-repo/brillig/src/opcodes.rs
@@ -98,6 +98,11 @@ pub enum BrilligOpcode {
         lhs: MemoryAddress,
         rhs: MemoryAddress,
     },
+    Cast {
+        destination: MemoryAddress,
+        source: MemoryAddress,
+        bit_size: u32,
+    },
     JumpIfNot {
         condition: MemoryAddress,
         location: Label,

diff --git a/acvm-repo/brillig_vm/src/black_box.rs b/acvm-repo/brillig_vm/src/black_box.rs
@@ -2,7 +2,7 @@ use acir::brillig::{BlackBoxOp, HeapArray, HeapVector, Value};
 use acir::{BlackBoxFunc, FieldElement};
 use acvm_blackbox_solver::{
     blake2s, blake3, ecdsa_secp256k1_verify, ecdsa_secp256r1_verify, keccak256, keccakf1600,
-    sha256, BlackBoxFunctionSolver, BlackBoxResolutionError,
+    sha256, sha256compression, BlackBoxFunctionSolver, BlackBoxResolutionError,
 };
 
 use crate::Memory;
@@ -185,7 +185,36 @@ pub(crate) fn evaluate_black_box<Solver: BlackBoxFunctionSolver>(
         BlackBoxOp::BigIntFromLeBytes { .. } => todo!(),
         BlackBoxOp::BigIntToLeBytes { .. } => todo!(),
         BlackBoxOp::Poseidon2Permutation { .. } => todo!(),
-        BlackBoxOp::Sha256Compression { .. } => todo!(),
+        BlackBoxOp::Sha256Compression { input, hash_values, output } => {
+            let mut message = [0; 16];
+            let inputs = read_heap_vector(memory, input);
+            if inputs.len() != 16 {
+                return Err(BlackBoxResolutionError::Failed(
+                    BlackBoxFunc::Sha256Compression,
+                    format!("Expected 16 inputs but encountered {}", &inputs.len()),
+                ));
+            }
+            for (i, input) in inputs.iter().enumerate() {
+                message[i] = input.to_u128() as u32;
+            }
+            let mut state = [0; 8];
+            let values = read_heap_vector(memory, hash_values);
+            if values.len() != 8 {
+                return Err(BlackBoxResolutionError::Failed(
+                    BlackBoxFunc::Sha256Compression,
+                    format!("Expected 8 values but encountered {}", &values.len()),
+                ));
+            }
+            for (i, value) in values.iter().enumerate() {
+                state[i] = value.to_u128() as u32;
+            }
+
+            sha256compression(&mut state, &message);
+            let state = state.map(|x| Value::from(x as u128));
+
+            memory.write_slice(memory.read_ref(output.pointer), &state);
+            Ok(())
+        }
     }
 }
 

diff --git a/acvm-repo/brillig_vm/src/lib.rs b/acvm-repo/brillig_vm/src/lib.rs
@@ -193,6 +193,12 @@ impl<'a, B: BlackBoxFunctionSolver> VM<'a, B> {
                     self.increment_program_counter()
                 }
             }
+            Opcode::Cast { destination: destination_address, source: source_address, bit_size } => {
+                let source_value = self.memory.read(*source_address);
+                let casted_value = self.cast(*bit_size, source_value);
+                self.memory.write(*destination_address, casted_value);
+                self.increment_program_counter()
+            }
             Opcode::Jump { location: destination } => self.set_program_counter(*destination),
             Opcode::JumpIf { condition, location: destination } => {
                 // Check if condition is true
@@ -511,6 +517,13 @@ impl<'a, B: BlackBoxFunctionSolver> VM<'a, B> {
             .write(result, FieldElement::from_be_bytes_reduce(&result_value.to_bytes_be()).into());
         Ok(())
     }
+
+    /// Casts a value to a different bit size.
+    fn cast(&self, bit_size: u32, value: Value) -> Value {
+        let lhs_big = BigUint::from_bytes_be(&value.to_field().to_be_bytes());
+        let mask = BigUint::from(2_u32).pow(bit_size) - 1_u32;
+        FieldElement::from_be_bytes_reduce(&(lhs_big & mask).to_bytes_be()).into()
+    }
 }
 
 pub(crate) struct DummyBlackBoxSolver;
@@ -708,6 +721,40 @@ mod tests {
         assert_eq!(output_value, Value::from(false));
     }
 
+    #[test]
+    fn cast_opcode() {
+        let calldata = vec![Value::from((2_u128.pow(32)) - 1)];
+
+        let opcodes = &[
+            Opcode::CalldataCopy {
+                destination_address: MemoryAddress::from(0),
+                size: 1,
+                offset: 0,
+            },
+            Opcode::Cast {
+                destination: MemoryAddress::from(1),
+                source: MemoryAddress::from(0),
+                bit_size: 8,
+            },
+            Opcode::Stop { return_data_offset: 1, return_data_size: 1 },
+        ];
+        let mut vm = VM::new(calldata, opcodes, vec![], &DummyBlackBoxSolver);
+
+        let status = vm.process_opcode();
+        assert_eq!(status, VMStatus::InProgress);
+
+        let status = vm.process_opcode();
+        assert_eq!(status, VMStatus::InProgress);
+
+        let status = vm.process_opcode();
+        assert_eq!(status, VMStatus::Finished { return_data_offset: 1, return_data_size: 1 });
+
+        let VM { memory, .. } = vm;
+
+        let casted_value = memory.read(MemoryAddress::from(1));
+        assert_eq!(casted_value, Value::from(2_u128.pow(8) - 1));
+    }
+
     #[test]
     fn mov_opcode() {
         let calldata = vec![Value::from(1u128), Value::from(2u128), Value::from(3u128)];