Motorola 68000

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Revision as of 04:36, 20 June 2022 by Superogue (talk | contribs) (The Motorola 68k processor)

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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 !!!


  • 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.

Motorola M68K Platforms