Implement the push and pall opcodes. The push opcode pushes an element to the stack. The pall opcode prints all values on the stack.
Implement the pint opcode. The pint opcode prints the value at the top of the stack.
Implement the pop opcode. The pop opcode removes the top element of the stack.
Implement the swap opcode. The swap opcode swaps the top two elements of the stack.
Implement the add opcode. The add opcode adds the top two elements of the stack.
Implement the nop opcode. The nop opcode doesn’t do anything.