User: Help me code a text based simulator for intel 4004 microprocessor in python. 
Assistant: Creating a text-based simulator for the Intel 4004 microprocessor in Python is a fun and educational project. The Intel 4004 is a 4-bit CPU, and working with it involves handling registers, a small addressable memory space, and instruction execution. Here, I'll guide you through setting up a basic simulation that supports a few instructions to get you started.

### Step 1: Define the CPU Structure

First, create a basic structure representing the CPU state, including registers and RAM.

```python
class Intel4004:
    def __init__(self):
        # Registers: 16 4-bit registers R0-R15
        self.registers = [0] * 16
        # Program Counter: 12-bit program counter
        self.pc = 0
        # Accumulator: 4-bit accumulator
        self.accumulator = 0
        # Carry flag
        self.carry_flag = 0
        # Memory: 4KB of ROM address space
        self.memory = [0] * 4096

    def load_program(self, program, start_address=0):
        """Load a program into memory starting at the given address."""
        for i, instruction in enumerate(program):
            self.memory[start_address + i] = instruction

    def fetch_instruction(self):
        """Fetch the next instruction from memory."""
        instruction = self.memory[self.pc]
        self.pc += 1
        return instruction

    def decode_execute(self, instruction):
        """Decode and execute the fetched instruction."""
        opcode = instruction >> 4  # Higher 4 bits
        operand = instruction & 0xF  # Lower 4 bits

        # Example of implementing a few basic instructions
        if opcode == 0x0:  # NOP
            pass
        elif opcode == 0x1:  # LDM Load immediate
            self.accumulator = operand
        elif opcode == 0x2:  # ADD
            result = self.accumulator + self.registers[operand] + self.carry_flag
            self.accumulator = result & 0xF
            self.carry_flag = (result >> 4) & 0x1
        elif opcode == 0x3:  # SUB
            result = self.accumulator - self.registers[operand] - self.carry_flag
            if result < 0:
                result += 16
                self.carry_flag = 1
            else:
                self.carry_flag = 0
            self.accumulator = result
        else:
            print(f"Unknown instruction: {hex(instruction)}")

    def run(self, start_address=0):
        """Run the program loaded into memory."""
        self.pc = start_address
        while True:
            instruction = self.fetch_instruction()
            if instruction is None:
                break  # End of program or invalid memory access
            self.decode_execute(instruction)
            self.debug_state()

    def debug_state(self):
        """Display the current state of the CPU for debugging."""
        print(f"PC: {self.pc:03} ACC: {self.accumulator:01X} "
              f"Carry: {self.carry_flag} Registers: {' '.join(f'{v:01X}' for v in self.registers)}")


# Example program and execution
program = [
    0x10,  # LDM 0
    0x21,  # ADD R1 (assuming R1 is 1)
    0x30,  # SUB R0 (assuming R0 is 0)
    0x00   # NOP or some form of halt instruction, end for simplification
]

cpu = Intel4004()
cpu.load_program(program, start_address=0)
cpu.run(start_address=0)
```

### Step 2: Expand Capabilities

The code provided implements a very basic simulator. To create a more complete simulator:

1. **Instruction Set Completeness**: Implement more of the 4004's instruction set, including jumps, logical operations, I/O commands, etc.
   
2. **Input/Output Simulation**: Implement methods for handling input and output ports.

3. **Testing and Debugging**: Run test programs to ensure the accuracy of the simulation, compare against expected results.

4. **Optimization and Cleanup**: Enhance the code for performance and use Python constructs effectively.

This simulator gives a foundation, and enhancing it will solidify your understanding of how the Intel 4004 operates. Happy coding!
User: here is the logic gates code i wrote :
def AND_Gate(a,b): 
    return a and b
def OR_Gate(a,b):
    return a or b
def NOT_Gate(a):
    return not a
def NAND_Gate(a,b):
    return not (a and b)
def NOR_Gate(a,b):
    return not a and not b
def XOR_Gate(a,b):
    return (a or b) and not (a and b)
def XNOR_Gate(a,b):
    return not ((a or b) and not (a and b))
- tell me how to use these to create a 4 bit register (for intel 4004 cpu).
Assistant: To create a 4-bit register using logic gates in Python, you need to use a combination of gates to simulate the behavior of a latch or flip-flop, which is the basic component of a register. The Intel 4004 uses 4-bit registers, and simulating these requires the use of a storage mechanism to hold the value, as well as logic for setting and clearing bits.

Here's how you might go about simulating a 4-bit register using your logic gate functions in Python:

1. **Define the Logic Gates**: These functions you've already created will serve as the basic building blocks.

2. **Create Flip-Flops**: Build a simple SR latch (set-reset) or D flip-flop to hold the bits in the register using logic gates.

3. **Implement a 4-Bit Register**: Use multiple flip-flops to store 4 bits, allowing you to set or reset each independently.

Here's a basic implementation using a D flip-flop, which is a common building block for registers:

```python
# Assume logic gate functions are defined as in your code

class DFlipFlop:
    """Simulate a D Flip-Flop using basic logic gates."""
    def __init__(self):
        self.Q = 0
        self.notQ = 1  # Q' is the complement of Q

    def clock_pulse(self, D):
        """Simulate a clock pulse, setting the state based on D input."""
        self.Q = D
        self.notQ = NOT_Gate(self.Q)

    def output(self):
        return self.Q


class FourBitRegister:
    """Simulate a 4-Bit Register using D Flip-Flops."""
    def __init__(self):
        self.bits = [DFlipFlop() for _ in range(4)]

    def load(self, data):
        """Load a 4-bit data value into the register."""
        for i in range(4):
            bit = (data >> i) & 1  # Extract the i-th bit from data
            self.bits[i].clock_pulse(bit)

    def read(self):
        """Read the current 4-bit value of the register."""
        return sum((ff.output() << i) for i, ff in enumerate(self.bits))


# Example usage
register = FourBitRegister()
register.load(0b1010)  # Load binary 1010 into the register
print(bin(register.read()))  # Should print 0b1010

register.load(0b1101)  # Load binary 1101 into the register
print(bin(register.read()))  # Should print 0b1101
```

### Explanation

1. **Flip-Flop (Basic Storage Element)**:
   - Each `DFlipFlop` simulates a single bit of storage. 
   - It has a method `clock_pulse` that updates its state based on the input `D`.
   - The `output` method returns the current state.

2. **Four-Bit Register**:
   - Composed of four `DFlipFlop` instances, each representing one bit of the register.
   - The `load` method takes a 4-bit data input and loads it into the register by setting each flip-flop.
   - The `read` method returns the combined value of all four bits.

### Note

This implementation models the basic behavior of a register using Python logic gates and simulates the concept of setting and reading bit values. The use of clock pulses and flip-flops here is conceptual rather than electrical, fitting for modeling in software.
User: i want to use the following as the global clock : 
import time

while True:
    time.sleep(1 / speed / 2)
    state = False
    print(f"State : False , Cycle : {cycle}")
    time.sleep(1 / speed / 2)
    state = True
    print(f"State : True , Cycle : {cycle}")
    cycle += 1
- can you modify the code to use this ?
Assistant: