Motorola 68000

Introduction

Wanting to start sizecoding on a Motorola 68k platform in this day and age can be tough.

So here is a bit of help to get you started:

The Motorola 68k processor

The Motorola 68k processor is a 16-bit Big-Endian format processor, using 32-bit register and addresses.

This means that instruction sizes on average are either 2 or 4 bytes each, and 6 bytes for longword / 32-bit instructions.

Note: The assigment direction is source,dest instead of dest,source !!!

Registers

• D0..D7 - 8 x 32 bit General Purpose Registers

• A0..A6 - 7 x 32 bit Address Registers

• A7 - 32-bit Stack-Address Register

Instructions timing

The number of cycles for each instruction is different depending of processor model in M68K family.

http://oldwww.nvg.ntnu.no/amiga/MC680x0_Sections/mc68000timing.HTML

Motorola M68K Platforms

• Atari ST - Atari ST Sizecoding information
• Atari Jaguar - Atari Jaguar Sizecoding information
• Commodore Amiga - Commodore Amiga Sizecoding information