How add new cpu opcodes at source code level

To add new cpu opcodes we need to change these files: simulate.H and simulate.C
So we have to proceed with these steps:

1) modify the file simulate.H
Go at the bottom of this file under the comment "//New Opcodes" and add your new opcode ABC
For example:
//New Opcodes
MDIV , // MDIV R, 10, M : (S>D) -- Calc Modulus and Division putting them into destination Registers
STX , // STX 0xFF , M : (S>D) -- Store immed. value into contents of [MemoryAddress] pointed by Register
+ ABC , // short description