Initial Query

Here is the description of a new assembly language: * 8 registers (R1, R2, R3, R4, R5, R6, R7, R8) that can hold integers. * 1 flag that can hold a boolean value (True or False). * 100 memory addresses (0-99) that can hold integers. * 1 instruction pointer that points to the current instruction being executed. Each instruction is of the form OP ARG1 ARG2 ... where ARGn can be either a register (e.g., R1) or a constant (e.g., 10). Labels are written with a lowercase word followed by colon. The assembly language supports the following instructions: * SET Rx C: Assigns the value C to register Rx. * ADD Rx Ry Rz: Adds the values of Ry and Rz and stores the result in Rx. * (similarly for SUB, MUL, DIV, MOD) * EQ Rx Ry: Sets the flag to True if Rx and Ry are equal, False otherwise. * (similarly for NEQ, LT (Rx < Ry), LTE, GT, GTE) * INC/DEC Rx: Increments/Decrements the value of Rx by one. * JMP L: Jumps to label L unconditionally. * JT/JF (jump if true / jump if false) L: Jumps to label L if the is set or not set. * LOAD Rx M: Loads the value at memory address M into register Rx. * STORE Rx M: Stores the value of register Rx into memory address M. * HCF: Stops the program (with pizzazz) For example here is a program to compute the first 20 square numbers (1, 4, 9, 16, 25, ...): SET R1 0 // Counter for storing squares SET R2 1 // Number to square loop: MUL R3 R2 R2 // R3 = R2 * R2 STORE R3 R1 // Store R3 at address R1 INC R1 // Increment address INC R2 // Increment number SET R3 20 EQ R1 R3 // Check if 20 squares are found JF loop // If not 20 squares found yet, continue finding end: HCF // Stop program Write me a python interpreter `evaluate(str)` that returns the resulting memory state after running the program. For example, `evaluate(program)` should return `[1, 4, 9, 16, 25, ...]` for the above program.

LLM Generation

Query

Here is the description of a new assembly language: * 8 registers (R1, R2, R3, R4, R5, R6, R7, R8) that can hold integers. * 1 flag that can hold a boolean value (True or False). * 100 memory addresses (0-99) that can hold integers. * 1 instruction pointer that points to the current instruction being executed. Each instruction is of the form OP ARG1 ARG2 ... where ARGn can be either a register (e.g., R1) or a constant (e.g., 10). Labels are written with a lowercase word followed by colon. The assembly language supports the following instructions: * SET Rx C: Assigns the value C to register Rx. * ADD Rx Ry Rz: Adds the values of Ry and Rz and stores the result in Rx. * (similarly for SUB, MUL, DIV, MOD) * EQ Rx Ry: Sets the flag to True if Rx and Ry are equal, False otherwise. * (similarly for NEQ, LT (Rx < Ry), LTE, GT, GTE) * INC/DEC Rx: Increments/Decrements the value of Rx by one. * JMP L: Jumps to label L unconditionally. * JT/JF (jump if true / jump if false) L: Jumps to label L if the is set or not set. * LOAD Rx M: Loads the value at memory address M into register Rx. * STORE Rx M: Stores the value of register Rx into memory address M. * HCF: Stops the program (with pizzazz) For example here is a program to compute the first 20 square numbers (1, 4, 9, 16, 25, ...): SET R1 0 // Counter for storing squares SET R2 1 // Number to square loop: MUL R3 R2 R2 // R3 = R2 * R2 STORE R3 R1 // Store R3 at address R1 INC R1 // Increment address INC R2 // Increment number SET R3 20 EQ R1 R3 // Check if 20 squares are found JF loop // If not 20 squares found yet, continue finding end: HCF // Stop program Write me a python interpreter `evaluate(str)` that returns the resulting memory state after running the program. For example, `evaluate(program)` should return `[1, 4, 9, 16, 25, ...]` for the above program.

Output

Okay, let's build the Python interpreter for this assembly language. 

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import re

class AssemblyError(Exception):
    """Custom exception for errors during assembly execution."""
    pass

def evaluate(program_str: str) -> list[int]:
    """
    Interprets the given assembly program string and returns the final memory state.

    Args:
        program_str: A string containing the assembly program.

    Returns:
        A list of 100 integers representing the final state of the memory.

    Raises:
        AssemblyError: If there's an error during parsing or execution.
    """

    # --- 1. Initialize Machine State ---
    registers = {f"R{i}": 0 for i in range(1, 9)}
    flag = False
    memory = [0] * 100
    ip = 0  # Instruction Pointer
    labels = {}
    instructions = []

    # --- 2. Parse the Program ---
    lines = program_str.strip().split('\n')
    line_number = 0 # For error reporting related to original source lines
    instruction_index = 0 # Index within the 'instructions' list

    for line in lines:
        line_number += 1
        original_line = line # Keep original for error messages
        
        # Remove comments and strip whitespace
        line = line.split('//', 1)[0].strip()

        if not line:
            continue # Skip empty lines or lines with only comments

        # Check for labels
        label_match = re.match(r'^([a-z][a-z0-9_]*):\s*$', line)
        if label_match:
            label_name = label_match.group(1)
            if label_name in labels:
                raise AssemblyError(f"Line {line_number}: Duplicate label '{label_name}'")
            labels[label_name] = instruction_index # Label points to the *next* instruction index
            continue # Don't add label line as an instruction

        # Parse instruction
        parts = line.split()
        if not parts:
             raise AssemblyError(f"Line {line_number}: Invalid instruction format: '{original_line}'")

        opcode = parts[0].upper()
        args = parts[1:]
        
        # Store instruction along with original line number for error context
        instructions.append({'opcode': opcode, 'args': args, 'line': line_number, 'original': original_line})
        instruction_index += 1
        
    # --- 3. Helper Function to Get Value (Register or Constant) ---
    def get_value(arg: str, line_num: int, original_line: str) -> int:
        if arg.upper() in registers:
            return registers[arg.upper()]
        try:
            return int(arg)
        except ValueError:
            raise AssemblyError(f"Line {line_num}: Invalid argument '{arg}'. Expected register (R1-R8) or integer constant in '{original_line}'")

    # --- 4. Execute Instructions ---
    max_instructions = len(instructions) * 1000 # Basic infinite loop prevention
    executed_count = 0

    while 0 <= ip < len(instructions):
        if executed_count > max_instructions:
             raise AssemblyError("Potential infinite loop detected (exceeded instruction limit)")
        executed_count += 1

        current_instruction = instructions[ip]
        opcode = current_instruction['opcode']
        args = current_instruction['args']
        line_num = current_instruction['line']
        original_line = current_instruction['original']

        # Assume sequential execution unless a jump happens
        next_ip = ip + 1 

        try:
            # --- Instruction Implementations ---
            if opcode == "SET":
                if len(args) != 2: raise AssemblyError(f"SET requires 2 arguments")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                value = get_value(args[1], line_num, original_line)
                registers[reg] = value
            
            elif opcode in ("ADD", "SUB", "MUL", "DIV", "MOD"):
                if len(args) != 3: raise AssemblyError(f"{opcode} requires 3 arguments")
                dest_reg = args[0].upper()
                if dest_reg not in registers: raise AssemblyError(f"Invalid destination register '{args[0]}'")
                val1 = get_value(args[1], line_num, original_line)
                val2 = get_value(args[2], line_num, original_line)

                if opcode == "ADD": registers[dest_reg] = val1 + val2
                elif opcode == "SUB": registers[dest_reg] = val1 - val2
                elif opcode == "MUL": registers[dest_reg] = val1 * val2
                elif opcode == "DIV":
                    if val2 == 0: raise AssemblyError(f"Division by zero")
                    registers[dest_reg] = val1 // val2 # Integer division
                elif opcode == "MOD":
                    if val2 == 0: raise AssemblyError(f"Modulo by zero")
                    registers[dest_reg] = val1 % val2

            elif opcode in ("EQ", "NEQ", "LT", "LTE", "GT", "GTE"):
                 if len(args) != 2: raise AssemblyError(f"{opcode} requires 2 arguments")
                 val1 = get_value(args[0], line_num, original_line)
                 val2 = get_value(args[1], line_num, original_line)

                 if opcode == "EQ": flag = (val1 == val2)
                 elif opcode == "NEQ": flag = (val1 != val2)
                 elif opcode == "LT": flag = (val1 < val2)
                 elif opcode == "LTE": flag = (val1 <= val2)
                 elif opcode == "GT": flag = (val1 > val2)
                 elif opcode == "GTE": flag = (val1 >= val2)

            elif opcode == "INC":
                if len(args) != 1: raise AssemblyError(f"INC requires 1 argument")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                registers[reg] += 1
            
            elif opcode == "DEC":
                if len(args) != 1: raise AssemblyError(f"DEC requires 1 argument")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                registers[reg] -= 1

            elif opcode == "JMP":
                if len(args) != 1: raise AssemblyError(f"JMP requires 1 argument (label)")
                label = args[0]
                if label not in labels: raise AssemblyError(f"Undefined label '{label}'")
                next_ip = labels[label] # Jump!

            elif opcode == "JT":
                if len(args) != 1: raise AssemblyError(f"JT requires 1 argument (label)")
                if flag:
                    label = args[0]
                    if label not in labels: raise AssemblyError(f"Undefined label '{label}'")
                    next_ip = labels[label] # Jump!
            
            elif opcode == "JF":
                if len(args) != 1: raise AssemblyError(f"JF requires 1 argument (label)")
                if not flag:
                    label = args[0]
                    if label not in labels: raise AssemblyError(f"Undefined label '{label}'")
                    next_ip = labels[label] # Jump!

            elif opcode == "LOAD":
                if len(args) != 2: raise AssemblyError(f"LOAD requires 2 arguments")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                mem_addr = get_value(args[1], line_num, original_line)
                if not (0 <= mem_addr < 100):
                    raise AssemblyError(f"Memory address {mem_addr} out of bounds (0-99)")
                registers[reg] = memory[mem_addr]

            elif opcode == "STORE":
                if len(args) != 2: raise AssemblyError(f"STORE requires 2 arguments")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                value_to_store = registers[reg]
                mem_addr = get_value(args[1], line_num, original_line)
                if not (0 <= mem_addr < 100):
                    raise AssemblyError(f"Memory address {mem_addr} out of bounds (0-99)")
                memory[mem_addr] = value_to_store

            elif opcode == "HCF":
                if len(args) != 0: raise AssemblyError(f"HCF takes no arguments")
                break # Halt and Catch Fire (with pizzazz!) - Stop execution

            else:
                raise AssemblyError(f"Unknown opcode '{opcode}'")

        except AssemblyError as e:
             # Add context to the error message
             raise AssemblyError(f"Line {line_num}: {e} in '{original_line}'") from e
        except IndexError:
             raise AssemblyError(f"Line {line_num}: Incorrect number of arguments for {opcode} in '{original_line}'")
        except Exception as e: # Catch unexpected errors
             raise AssemblyError(f"Line {line_num}: Unexpected error '{e}' during execution of '{original_line}'") from e


        # Move to the next instruction
        ip = next_ip

    # --- 5. Return Final Memory State ---
    return memory

# --- Example Usage ---
program = """
    SET R1 0      // Counter for storing squares (memory address)
    SET R2 1      // Number to square

loop:
    MUL R3 R2 R2  // R3 = R2 * R2
    STORE R3 R1   // Store R3 at address R1 (which starts at 0)
    INC R1        // Increment address for next store
    INC R2        // Increment number to square
    SET R4 20     // Target number of squares
    EQ R1 R4      // Check if R1 (address counter) has reached 20
    JF loop       // If flag is False (R1 != 20), jump back to loop

end:             // Optional label, program stops anyway
    HCF           // Stop program
"""

try:
    final_memory = evaluate(program)
    # Print the first 20 memory locations (where the squares were stored)
    print(f"Final memory state (first 20): {final_memory[:20]}") 
    # Verify the result
    expected = [i*i for i in range(1, 21)]
    print(f"Expected result (first 20): {expected}")
    assert final_memory[:20] == expected
    print("\nProgram executed successfully and result matches expected.")

    # Example of another program (simple addition)
    program_add = """
        SET R1 10
        SET R2 5
        ADD R3 R1 R2 // R3 = 10 + 5 = 15
        STORE R3 50  // Store 15 at address 50
        HCF
    """
    final_memory_add = evaluate(program_add)
    print(f"\nAddition program result (memory[50]): {final_memory_add[50]}")
    assert final_memory_add[50] == 15
    print("Addition program executed successfully.")
    
    # Example demonstrating conditional jump
    program_cond = """
        SET R1 5
        SET R2 10
        LT R1 R2     // Set flag = (5 < 10) -> True
        JF skip_store // Should NOT jump as flag is True
        SET R3 999
        STORE R3 0   // Store 999 at address 0
    skip_store:
        SET R4 111
        STORE R4 1   // Store 111 at address 1
        HCF
    """
    final_memory_cond = evaluate(program_cond)
    print(f"\nConditional program result (memory[0], memory[1]): ({final_memory_cond[0]}, {final_memory_cond[1]})")
    assert final_memory_cond[0] == 999
    assert final_memory_cond[1] == 111
    print("Conditional program executed successfully.")


except AssemblyError as e:
    print(f"Assembly Error: {e}")
except Exception as e:
    print(f"An unexpected Python error occurred: {e}")
**Explanation:** 1. **`AssemblyError` Class:** A custom exception class is defined for better error handling specific to this interpreter. 2. **`evaluate(program_str)` Function:** * **Initialization:** Sets up the `registers` dictionary (R1-R8 initialized to 0), the boolean `flag`, the `memory` list (100 zeros), and the `ip` (instruction pointer) to 0. `labels` dictionary and `instructions` list are also initialized. * **Parsing:** * Splits the input `program_str` into lines. * Iterates through each line: * Removes comments (`//...`). * Strips leading/trailing whitespace. * Skips empty lines. * Uses a regular expression (`re.match`) to detect labels (lowercase word followed by `:`). If found, stores the label name and the *current* instruction index (`instruction_index`) in the `labels` dictionary. The label points to the *next* instruction that will be added. * If not a label, splits the line into parts (opcode and arguments). * Converts the opcode to uppercase for case-insensitive matching. * Appends a dictionary containing the `opcode`, `args`, original `line` number, and `original` line content to the `instructions` list. This helps with error reporting. * Increments `instruction_index`. * **`get_value` Helper:** This crucial internal function takes an argument string (`arg`). It checks if the argument is a register name (R1-R8). If yes, it returns the value from the `registers` dictionary. Otherwise, it tries to convert the argument to an integer (constant). It raises an `AssemblyError` if the argument is neither a valid register nor an integer. It also takes `line_num` and `original_line` for better error messages. * **Execution Loop:** * The `while 0 <= ip < len(instructions):` loop runs as long as the instruction pointer is valid. * **Infinite Loop Prevention:** A simple counter (`executed_count`) is added to stop execution if it seems to be running excessively long, preventing true infinite loops from freezing the interpreter. * Fetches the current instruction dictionary based on `ip`. * Extracts `opcode`, `args`, `line_num`, and `original_line`. * Sets `next_ip = ip + 1` assuming sequential execution. Jumps will modify `next_ip`. * Uses a large `if/elif/else` block to handle each `opcode`: * **Argument Validation:** Each instruction handler first checks if it received the correct number of arguments. * **Register/Value Retrieval:** Uses `get_value` to resolve arguments into integer values. * **Operation:** Performs the specific operation (arithmetic, comparison, memory access, etc.), updating registers, the flag, or memory accordingly. * **Error Handling:** Includes checks for division/modulo by zero and out-of-bounds memory access. * **Jumps:** `JMP`, `JT`, `JF` look up the target label in the `labels` dictionary and update `next_ip` if the condition (or unconditional for `JMP`) is met. Raises an error if the label is undefined. * **HCF:** Breaks out of the execution loop. * **Unknown Opcode:** Raises an error if the opcode isn't recognized. * **Error Context:** `try...except` blocks wrap the instruction execution. If an `AssemblyError` occurs, it's re-raised with the line number and original line content for better debugging. Unexpected Python errors are also caught and wrapped. * Updates `ip = next_ip` for the next iteration. * **Return Value:** After the loop finishes (due to `HCF` or reaching the end), the function returns the final `memory` list. 3. **Example Usage:** Demonstrates how to call `evaluate` with the square number program and prints the first 20 elements of the resulting memory. It also includes assertions to verify the output and examples for addition and conditional jumps. Error handling is shown with a `try...except AssemblyError`.

Extract Code

I extracted the following code from that output: 

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import re

class AssemblyError(Exception):
    """Custom exception for errors during assembly execution."""
    pass

def evaluate(program_str: str) -> list[int]:
    """
    Interprets the given assembly program string and returns the final memory state.

    Args:
        program_str: A string containing the assembly program.

    Returns:
        A list of 100 integers representing the final state of the memory.

    Raises:
        AssemblyError: If there's an error during parsing or execution.
    """

    # --- 1. Initialize Machine State ---
    registers = {f"R{i}": 0 for i in range(1, 9)}
    flag = False
    memory = [0] * 100
    ip = 0  # Instruction Pointer
    labels = {}
    instructions = []

    # --- 2. Parse the Program ---
    lines = program_str.strip().split('\n')
    line_number = 0 # For error reporting related to original source lines
    instruction_index = 0 # Index within the 'instructions' list

    for line in lines:
        line_number += 1
        original_line = line # Keep original for error messages
        
        # Remove comments and strip whitespace
        line = line.split('//', 1)[0].strip()

        if not line:
            continue # Skip empty lines or lines with only comments

        # Check for labels
        label_match = re.match(r'^([a-z][a-z0-9_]*):\s*$', line)
        if label_match:
            label_name = label_match.group(1)
            if label_name in labels:
                raise AssemblyError(f"Line {line_number}: Duplicate label '{label_name}'")
            labels[label_name] = instruction_index # Label points to the *next* instruction index
            continue # Don't add label line as an instruction

        # Parse instruction
        parts = line.split()
        if not parts:
             raise AssemblyError(f"Line {line_number}: Invalid instruction format: '{original_line}'")

        opcode = parts[0].upper()
        args = parts[1:]
        
        # Store instruction along with original line number for error context
        instructions.append({'opcode': opcode, 'args': args, 'line': line_number, 'original': original_line})
        instruction_index += 1
        
    # --- 3. Helper Function to Get Value (Register or Constant) ---
    def get_value(arg: str, line_num: int, original_line: str) -> int:
        if arg.upper() in registers:
            return registers[arg.upper()]
        try:
            return int(arg)
        except ValueError:
            raise AssemblyError(f"Line {line_num}: Invalid argument '{arg}'. Expected register (R1-R8) or integer constant in '{original_line}'")

    # --- 4. Execute Instructions ---
    max_instructions = len(instructions) * 1000 # Basic infinite loop prevention
    executed_count = 0

    while 0 <= ip < len(instructions):
        if executed_count > max_instructions:
             raise AssemblyError("Potential infinite loop detected (exceeded instruction limit)")
        executed_count += 1

        current_instruction = instructions[ip]
        opcode = current_instruction['opcode']
        args = current_instruction['args']
        line_num = current_instruction['line']
        original_line = current_instruction['original']

        # Assume sequential execution unless a jump happens
        next_ip = ip + 1 

        try:
            # --- Instruction Implementations ---
            if opcode == "SET":
                if len(args) != 2: raise AssemblyError(f"SET requires 2 arguments")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                value = get_value(args[1], line_num, original_line)
                registers[reg] = value
            
            elif opcode in ("ADD", "SUB", "MUL", "DIV", "MOD"):
                if len(args) != 3: raise AssemblyError(f"{opcode} requires 3 arguments")
                dest_reg = args[0].upper()
                if dest_reg not in registers: raise AssemblyError(f"Invalid destination register '{args[0]}'")
                val1 = get_value(args[1], line_num, original_line)
                val2 = get_value(args[2], line_num, original_line)

                if opcode == "ADD": registers[dest_reg] = val1 + val2
                elif opcode == "SUB": registers[dest_reg] = val1 - val2
                elif opcode == "MUL": registers[dest_reg] = val1 * val2
                elif opcode == "DIV":
                    if val2 == 0: raise AssemblyError(f"Division by zero")
                    registers[dest_reg] = val1 // val2 # Integer division
                elif opcode == "MOD":
                    if val2 == 0: raise AssemblyError(f"Modulo by zero")
                    registers[dest_reg] = val1 % val2

            elif opcode in ("EQ", "NEQ", "LT", "LTE", "GT", "GTE"):
                 if len(args) != 2: raise AssemblyError(f"{opcode} requires 2 arguments")
                 val1 = get_value(args[0], line_num, original_line)
                 val2 = get_value(args[1], line_num, original_line)

                 if opcode == "EQ": flag = (val1 == val2)
                 elif opcode == "NEQ": flag = (val1 != val2)
                 elif opcode == "LT": flag = (val1 < val2)
                 elif opcode == "LTE": flag = (val1 <= val2)
                 elif opcode == "GT": flag = (val1 > val2)
                 elif opcode == "GTE": flag = (val1 >= val2)

            elif opcode == "INC":
                if len(args) != 1: raise AssemblyError(f"INC requires 1 argument")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                registers[reg] += 1
            
            elif opcode == "DEC":
                if len(args) != 1: raise AssemblyError(f"DEC requires 1 argument")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                registers[reg] -= 1

            elif opcode == "JMP":
                if len(args) != 1: raise AssemblyError(f"JMP requires 1 argument (label)")
                label = args[0]
                if label not in labels: raise AssemblyError(f"Undefined label '{label}'")
                next_ip = labels[label] # Jump!

            elif opcode == "JT":
                if len(args) != 1: raise AssemblyError(f"JT requires 1 argument (label)")
                if flag:
                    label = args[0]
                    if label not in labels: raise AssemblyError(f"Undefined label '{label}'")
                    next_ip = labels[label] # Jump!
            
            elif opcode == "JF":
                if len(args) != 1: raise AssemblyError(f"JF requires 1 argument (label)")
                if not flag:
                    label = args[0]
                    if label not in labels: raise AssemblyError(f"Undefined label '{label}'")
                    next_ip = labels[label] # Jump!

            elif opcode == "LOAD":
                if len(args) != 2: raise AssemblyError(f"LOAD requires 2 arguments")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                mem_addr = get_value(args[1], line_num, original_line)
                if not (0 <= mem_addr < 100):
                    raise AssemblyError(f"Memory address {mem_addr} out of bounds (0-99)")
                registers[reg] = memory[mem_addr]

            elif opcode == "STORE":
                if len(args) != 2: raise AssemblyError(f"STORE requires 2 arguments")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                value_to_store = registers[reg]
                mem_addr = get_value(args[1], line_num, original_line)
                if not (0 <= mem_addr < 100):
                    raise AssemblyError(f"Memory address {mem_addr} out of bounds (0-99)")
                memory[mem_addr] = value_to_store

            elif opcode == "HCF":
                if len(args) != 0: raise AssemblyError(f"HCF takes no arguments")
                break # Halt and Catch Fire (with pizzazz!) - Stop execution

            else:
                raise AssemblyError(f"Unknown opcode '{opcode}'")

        except AssemblyError as e:
             # Add context to the error message
             raise AssemblyError(f"Line {line_num}: {e} in '{original_line}'") from e
        except IndexError:
             raise AssemblyError(f"Line {line_num}: Incorrect number of arguments for {opcode} in '{original_line}'")
        except Exception as e: # Catch unexpected errors
             raise AssemblyError(f"Line {line_num}: Unexpected error '{e}' during execution of '{original_line}'") from e


        # Move to the next instruction
        ip = next_ip

    # --- 5. Return Final Memory State ---
    return memory

# --- Example Usage ---
program = """
    SET R1 0      // Counter for storing squares (memory address)
    SET R2 1      // Number to square

loop:
    MUL R3 R2 R2  // R3 = R2 * R2
    STORE R3 R1   // Store R3 at address R1 (which starts at 0)
    INC R1        // Increment address for next store
    INC R2        // Increment number to square
    SET R4 20     // Target number of squares
    EQ R1 R4      // Check if R1 (address counter) has reached 20
    JF loop       // If flag is False (R1 != 20), jump back to loop

end:             // Optional label, program stops anyway
    HCF           // Stop program
"""

try:
    final_memory = evaluate(program)
    # Print the first 20 memory locations (where the squares were stored)
    print(f"Final memory state (first 20): {final_memory[:20]}") 
    # Verify the result
    expected = [i*i for i in range(1, 21)]
    print(f"Expected result (first 20): {expected}")
    assert final_memory[:20] == expected
    print("\nProgram executed successfully and result matches expected.")

    # Example of another program (simple addition)
    program_add = """
        SET R1 10
        SET R2 5
        ADD R3 R1 R2 // R3 = 10 + 5 = 15
        STORE R3 50  // Store 15 at address 50
        HCF
    """
    final_memory_add = evaluate(program_add)
    print(f"\nAddition program result (memory[50]): {final_memory_add[50]}")
    assert final_memory_add[50] == 15
    print("Addition program executed successfully.")
    
    # Example demonstrating conditional jump
    program_cond = """
        SET R1 5
        SET R2 10
        LT R1 R2     // Set flag = (5 < 10) -> True
        JF skip_store // Should NOT jump as flag is True
        SET R3 999
        STORE R3 0   // Store 999 at address 0
    skip_store:
        SET R4 111
        STORE R4 1   // Store 111 at address 1
        HCF
    """
    final_memory_cond = evaluate(program_cond)
    print(f"\nConditional program result (memory[0], memory[1]): ({final_memory_cond[0]}, {final_memory_cond[1]})")
    assert final_memory_cond[0] == 999
    assert final_memory_cond[1] == 111
    print("Conditional program executed successfully.")


except AssemblyError as e:
    print(f"Assembly Error: {e}")
except Exception as e:
    print(f"An unexpected Python error occurred: {e}")

Run Code Interpreter

Running the following program: 

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import re

class AssemblyError(Exception):
    """Custom exception for errors during assembly execution."""
    pass

def evaluate(program_str: str) -> list[int]:
    """
    Interprets the given assembly program string and returns the final memory state.

    Args:
        program_str: A string containing the assembly program.

    Returns:
        A list of 100 integers representing the final state of the memory.

    Raises:
        AssemblyError: If there's an error during parsing or execution.
    """

    # --- 1. Initialize Machine State ---
    registers = {f"R{i}": 0 for i in range(1, 9)}
    flag = False
    memory = [0] * 100
    ip = 0  # Instruction Pointer
    labels = {}
    instructions = []

    # --- 2. Parse the Program ---
    lines = program_str.strip().split('\n')
    line_number = 0 # For error reporting related to original source lines
    instruction_index = 0 # Index within the 'instructions' list

    for line in lines:
        line_number += 1
        original_line = line # Keep original for error messages
        
        # Remove comments and strip whitespace
        line = line.split('//', 1)[0].strip()

        if not line:
            continue # Skip empty lines or lines with only comments

        # Check for labels
        label_match = re.match(r'^([a-z][a-z0-9_]*):\s*$', line)
        if label_match:
            label_name = label_match.group(1)
            if label_name in labels:
                raise AssemblyError(f"Line {line_number}: Duplicate label '{label_name}'")
            labels[label_name] = instruction_index # Label points to the *next* instruction index
            continue # Don't add label line as an instruction

        # Parse instruction
        parts = line.split()
        if not parts:
             raise AssemblyError(f"Line {line_number}: Invalid instruction format: '{original_line}'")

        opcode = parts[0].upper()
        args = parts[1:]
        
        # Store instruction along with original line number for error context
        instructions.append({'opcode': opcode, 'args': args, 'line': line_number, 'original': original_line})
        instruction_index += 1
        
    # --- 3. Helper Function to Get Value (Register or Constant) ---
    def get_value(arg: str, line_num: int, original_line: str) -> int:
        if arg.upper() in registers:
            return registers[arg.upper()]
        try:
            return int(arg)
        except ValueError:
            raise AssemblyError(f"Line {line_num}: Invalid argument '{arg}'. Expected register (R1-R8) or integer constant in '{original_line}'")

    # --- 4. Execute Instructions ---
    max_instructions = len(instructions) * 1000 # Basic infinite loop prevention
    executed_count = 0

    while 0 <= ip < len(instructions):
        if executed_count > max_instructions:
             raise AssemblyError("Potential infinite loop detected (exceeded instruction limit)")
        executed_count += 1

        current_instruction = instructions[ip]
        opcode = current_instruction['opcode']
        args = current_instruction['args']
        line_num = current_instruction['line']
        original_line = current_instruction['original']

        # Assume sequential execution unless a jump happens
        next_ip = ip + 1 

        try:
            # --- Instruction Implementations ---
            if opcode == "SET":
                if len(args) != 2: raise AssemblyError(f"SET requires 2 arguments")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                value = get_value(args[1], line_num, original_line)
                registers[reg] = value
            
            elif opcode in ("ADD", "SUB", "MUL", "DIV", "MOD"):
                if len(args) != 3: raise AssemblyError(f"{opcode} requires 3 arguments")
                dest_reg = args[0].upper()
                if dest_reg not in registers: raise AssemblyError(f"Invalid destination register '{args[0]}'")
                val1 = get_value(args[1], line_num, original_line)
                val2 = get_value(args[2], line_num, original_line)

                if opcode == "ADD": registers[dest_reg] = val1 + val2
                elif opcode == "SUB": registers[dest_reg] = val1 - val2
                elif opcode == "MUL": registers[dest_reg] = val1 * val2
                elif opcode == "DIV":
                    if val2 == 0: raise AssemblyError(f"Division by zero")
                    registers[dest_reg] = val1 // val2 # Integer division
                elif opcode == "MOD":
                    if val2 == 0: raise AssemblyError(f"Modulo by zero")
                    registers[dest_reg] = val1 % val2

            elif opcode in ("EQ", "NEQ", "LT", "LTE", "GT", "GTE"):
                 if len(args) != 2: raise AssemblyError(f"{opcode} requires 2 arguments")
                 val1 = get_value(args[0], line_num, original_line)
                 val2 = get_value(args[1], line_num, original_line)

                 if opcode == "EQ": flag = (val1 == val2)
                 elif opcode == "NEQ": flag = (val1 != val2)
                 elif opcode == "LT": flag = (val1 < val2)
                 elif opcode == "LTE": flag = (val1 <= val2)
                 elif opcode == "GT": flag = (val1 > val2)
                 elif opcode == "GTE": flag = (val1 >= val2)

            elif opcode == "INC":
                if len(args) != 1: raise AssemblyError(f"INC requires 1 argument")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                registers[reg] += 1
            
            elif opcode == "DEC":
                if len(args) != 1: raise AssemblyError(f"DEC requires 1 argument")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                registers[reg] -= 1

            elif opcode == "JMP":
                if len(args) != 1: raise AssemblyError(f"JMP requires 1 argument (label)")
                label = args[0]
                if label not in labels: raise AssemblyError(f"Undefined label '{label}'")
                next_ip = labels[label] # Jump!

            elif opcode == "JT":
                if len(args) != 1: raise AssemblyError(f"JT requires 1 argument (label)")
                if flag:
                    label = args[0]
                    if label not in labels: raise AssemblyError(f"Undefined label '{label}'")
                    next_ip = labels[label] # Jump!
            
            elif opcode == "JF":
                if len(args) != 1: raise AssemblyError(f"JF requires 1 argument (label)")
                if not flag:
                    label = args[0]
                    if label not in labels: raise AssemblyError(f"Undefined label '{label}'")
                    next_ip = labels[label] # Jump!

            elif opcode == "LOAD":
                if len(args) != 2: raise AssemblyError(f"LOAD requires 2 arguments")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                mem_addr = get_value(args[1], line_num, original_line)
                if not (0 <= mem_addr < 100):
                    raise AssemblyError(f"Memory address {mem_addr} out of bounds (0-99)")
                registers[reg] = memory[mem_addr]

            elif opcode == "STORE":
                if len(args) != 2: raise AssemblyError(f"STORE requires 2 arguments")
                reg = args[0].upper()
                if reg not in registers: raise AssemblyError(f"Invalid register '{args[0]}'")
                value_to_store = registers[reg]
                mem_addr = get_value(args[1], line_num, original_line)
                if not (0 <= mem_addr < 100):
                    raise AssemblyError(f"Memory address {mem_addr} out of bounds (0-99)")
                memory[mem_addr] = value_to_store

            elif opcode == "HCF":
                if len(args) != 0: raise AssemblyError(f"HCF takes no arguments")
                break # Halt and Catch Fire (with pizzazz!) - Stop execution

            else:
                raise AssemblyError(f"Unknown opcode '{opcode}'")

        except AssemblyError as e:
             # Add context to the error message
             raise AssemblyError(f"Line {line_num}: {e} in '{original_line}'") from e
        except IndexError:
             raise AssemblyError(f"Line {line_num}: Incorrect number of arguments for {opcode} in '{original_line}'")
        except Exception as e: # Catch unexpected errors
             raise AssemblyError(f"Line {line_num}: Unexpected error '{e}' during execution of '{original_line}'") from e


        # Move to the next instruction
        ip = next_ip

    # --- 5. Return Final Memory State ---
    return memory

# --- Example Usage ---
program = """
    SET R1 0      // Counter for storing squares (memory address)
    SET R2 1      // Number to square

loop:
    MUL R3 R2 R2  // R3 = R2 * R2
    STORE R3 R1   // Store R3 at address R1 (which starts at 0)
    INC R1        // Increment address for next store
    INC R2        // Increment number to square
    SET R4 20     // Target number of squares
    EQ R1 R4      // Check if R1 (address counter) has reached 20
    JF loop       // If flag is False (R1 != 20), jump back to loop

end:             // Optional label, program stops anyway
    HCF           // Stop program
"""

try:
    final_memory = evaluate(program)
    # Print the first 20 memory locations (where the squares were stored)
    print(f"Final memory state (first 20): {final_memory[:20]}") 
    # Verify the result
    expected = [i*i for i in range(1, 21)]
    print(f"Expected result (first 20): {expected}")
    assert final_memory[:20] == expected
    print("\nProgram executed successfully and result matches expected.")

    # Example of another program (simple addition)
    program_add = """
        SET R1 10
        SET R2 5
        ADD R3 R1 R2 // R3 = 10 + 5 = 15
        STORE R3 50  // Store 15 at address 50
        HCF
    """
    final_memory_add = evaluate(program_add)
    print(f"\nAddition program result (memory[50]): {final_memory_add[50]}")
    assert final_memory_add[50] == 15
    print("Addition program executed successfully.")
    
    # Example demonstrating conditional jump
    program_cond = """
        SET R1 5
        SET R2 10
        LT R1 R2     // Set flag = (5 < 10) -> True
        JF skip_store // Should NOT jump as flag is True
        SET R3 999
        STORE R3 0   // Store 999 at address 0
    skip_store:
        SET R4 111
        STORE R4 1   // Store 111 at address 1
        HCF
    """
    final_memory_cond = evaluate(program_cond)
    print(f"\nConditional program result (memory[0], memory[1]): ({final_memory_cond[0]}, {final_memory_cond[1]})")
    assert final_memory_cond[0] == 999
    assert final_memory_cond[1] == 111
    print("Conditional program executed successfully.")


except AssemblyError as e:
    print(f"Assembly Error: {e}")
except Exception as e:
    print(f"An unexpected Python error occurred: {e}")






answer = evaluate("""
    SET R1 0
    SET R2 1
loop:
    MUL R3 R2 R2
    STORE R3 R1
    INC R1
    INC R2
    SET R3 20
    EQ R1 R3
    JF loop
""")[:10]
expected = [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
assert answer == expected, f'Wrong answer; got {answer} instead of {expected}'

answer = evaluate("""

SET R1 2          // Starting number to check for prime

start_find_primes:

    JMP is_prime // Control will return after executing is_prime with R1 as input and R2 containing the result

ready_prime:
    SET R7 1
    EQ R2 R7        // Check if R2 is 1 (prime)
    JF increment  // If not prime, skip storing and increment the number

    // Store prime number in memory and increment count
    STORE R1 R8   // Store prime number at address pointed by R8
    INC R8        // Increment prime count

    // Check if 100 primes are found
    SET R7 100
    EQ R8 R7
    JF increment  // If not 100 primes found yet, continue finding

    JMP end        // If 100 primes found, end program

increment:
    INC R1         // Increment number to check for prime
    JMP start_find_primes // Check next number

is_prime:
    SET R2 1       // Assume number is prime initially
    SET R3 2       // Start divisor from 2

start_loop:        // Label to start the loop
    // Check if we have exceeded the square root of R1
    MUL R4 R3 R3   // R4 = R3 * R3
    GT R4 R1       // Set flag if R4 > R1
    JT is_prime_end        // If not exceeded, continue; else, end loop

    MOD R6 R1 R3   // R6 = R1 % R3
    SET R7 0
    EQ R7 R6     // Check if R6 is 0
    JT not_prime   // If yes, number is not prime

    INC R3         // Increment divisor
    JMP start_loop // Repeat loop

not_prime:
    SET R2 0       // Set result to 0 (not prime)

is_prime_end:
    JMP ready_prime

end:
""")[:10]
expected = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
assert answer == expected, f'Wrong answer; got {answer} instead of {expected}'
print('All tests passed')
And got the output: Final memory state (first 20): [1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400] Expected result (first 20): [1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400] Program executed successfully and result matches expected. Addition program result (memory[50]): 15 Addition program executed successfully. Conditional program result (memory[0], memory[1]): (999, 111) Conditional program executed successfully. Traceback (most recent call last): File "/usr/src/app/main.py", line 290, in <module> answer = evaluate(""" ^^^^^^^^^^^^ File "/usr/src/app/main.py", line 81, in evaluate raise AssemblyError("Potential infinite loop detected (exceeded instruction limit)") AssemblyError: Potential infinite loop detected (exceeded instruction limit)

Substring Evaluation

Testing if the previous output contains the string All tests passed: False