Z O O F W A R E

Today I have started the momentous task of re-writing my Z80 emulator in C. It would have been possible to simply convert much of the C# code to C, but since I have learnt so much since I started writing it almost a year ago, I have decided to completely overhaul it.

Progress has been remarkably quick, with over a hundred of the most used opcodes implemented so far. One problem with the C# version was that as I wanted a built in disassembler and thought it would be cleaner, I had to have an individual method for each opcode which added the opcode’s mnemonic to the debug output. This time around, I have placed the vast majority of the opcode code in the switch statement, with common parts of code outsourced to inline functions. This has made the code a lot cleaner and manageable. To handle disassembly, I have created a Python script to convert a list of all the Z80 opcodes and their mnemonics to a C function which contains a huge switch statement to return the mnemonic. It might not be the fastest method, but it’s adequate for debugging.

This has been my first experience with C, and so far, it’s been a good one, I love the low level sexiness of it all. Would implementing a C standard library for Master System development using SDCC be too ambitious?