From d1400acb764dafcb4999733a352b2af246ec6fc7 Mon Sep 17 00:00:00 2001
From: jeanmon <jean@aztecprotocol.com>
Date: Thu, 18 Apr 2024 11:41:00 +0000
Subject: [PATCH] 5466: deserialization and execution support for CAST

---
 .../vm/avm_trace/avm_deserialization.cpp      |  2 +
 .../vm/avm_trace/avm_execution.cpp            |  7 ++++
 .../vm/tests/avm_execution.test.cpp           | 41 +++++++++++++++++++
 3 files changed, 50 insertions(+)

diff --git a/barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_deserialization.cpp b/barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_deserialization.cpp
index 2590e5e298a..9b9c4bd7b3e 100644
--- a/barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_deserialization.cpp
+++ b/barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_deserialization.cpp
@@ -35,6 +35,8 @@ const std::unordered_map<OpCode, std::vector<OperandType>> OPCODE_WIRE_FORMAT =
     { OpCode::AND, three_operand_format },
     { OpCode::OR, three_operand_format },
     { OpCode::XOR, three_operand_format },
+    // Compute - Type Conversions
+    { OpCode::CAST, { OperandType::INDIRECT, OperandType::TAG, OperandType::UINT32, OperandType::UINT32 } },
     // Execution Environment - Calldata
     { OpCode::CALLDATACOPY, { OperandType::INDIRECT, OperandType::UINT32, OperandType::UINT32, OperandType::UINT32 } },
     // Machine State - Internal Control Flow
diff --git a/barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_execution.cpp b/barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_execution.cpp
index 1e018d647d6..e25d9ad1807 100644
--- a/barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_execution.cpp
+++ b/barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_execution.cpp
@@ -180,6 +180,13 @@ std::vector<Row> Execution::gen_trace(std::vector<Instruction> const& instructio
                                  std::get<uint32_t>(inst.operands.at(4)),
                                  std::get<AvmMemoryTag>(inst.operands.at(1)));
             break;
+            // Compute - Type Conversions
+        case OpCode::CAST:
+            trace_builder.op_cast(std::get<uint8_t>(inst.operands.at(0)),
+                                  std::get<uint32_t>(inst.operands.at(2)),
+                                  std::get<uint32_t>(inst.operands.at(3)),
+                                  std::get<AvmMemoryTag>(inst.operands.at(1)));
+            break;
             // Execution Environment - Calldata
         case OpCode::CALLDATACOPY:
             trace_builder.calldata_copy(std::get<uint8_t>(inst.operands.at(0)),
diff --git a/barretenberg/cpp/src/barretenberg/vm/tests/avm_execution.test.cpp b/barretenberg/cpp/src/barretenberg/vm/tests/avm_execution.test.cpp
index f505eb16ce5..2639e9fb979 100644
--- a/barretenberg/cpp/src/barretenberg/vm/tests/avm_execution.test.cpp
+++ b/barretenberg/cpp/src/barretenberg/vm/tests/avm_execution.test.cpp
@@ -607,6 +607,47 @@ TEST_F(AvmExecutionTests, indMovOpcode)
     gen_proof_and_validate(bytecode, std::move(trace), {});
 }
 
+// Positive test for SET and CAST opcodes
+TEST_F(AvmExecutionTests, setAndCastOpcodes)
+{
+    std::string bytecode_hex = to_hex(OpCode::SET) +      // opcode SET
+                               "00"                       // Indirect flag
+                               "02"                       // U16
+                               "B813"                     // val 47123
+                               "00000011"                 // dst_offset 17
+                               + to_hex(OpCode::CAST) +   // opcode CAST
+                               "00"                       // Indirect flag
+                               "01"                       // U8
+                               "00000011"                 // addr a
+                               "00000012"                 // addr casted a
+                               + to_hex(OpCode::RETURN) + // opcode RETURN
+                               "00"                       // Indirect flag
+                               "00000000"                 // ret offset 0
+                               "00000000";                // ret size 0
+
+    auto bytecode = hex_to_bytes(bytecode_hex);
+    auto instructions = Deserialization::parse(bytecode);
+
+    ASSERT_THAT(instructions, SizeIs(3));
+
+    // SUB
+    EXPECT_THAT(instructions.at(1),
+                AllOf(Field(&Instruction::op_code, OpCode::CAST),
+                      Field(&Instruction::operands,
+                            ElementsAre(VariantWith<uint8_t>(0),
+                                        VariantWith<AvmMemoryTag>(AvmMemoryTag::U8),
+                                        VariantWith<uint32_t>(17),
+                                        VariantWith<uint32_t>(18)))));
+
+    auto trace = Execution::gen_trace(instructions);
+
+    // Find the first row enabling the cast selector
+    auto row = std::ranges::find_if(trace.begin(), trace.end(), [](Row r) { return r.avm_main_sel_op_cast == 1; });
+    EXPECT_EQ(row->avm_main_ic, 19); // 0XB813 --> 0X13 = 19
+
+    gen_proof_and_validate(bytecode, std::move(trace), {});
+}
+
 // Negative test detecting an invalid opcode byte.
 TEST_F(AvmExecutionTests, invalidOpcode)
 {