Motorola 6800 addressing modes

1 · Tobias V. Langhoff · April 8, 2020, midnight
The MC6800’s addressing modes have a few things to be aware of. This post is part of a series on writing an emulator for the DREAM 6800 computer. Read the DREAM 6800 posts and look at the emulator’s repository. The first step in emulating an M6800 system is to decode some instructions. The MC6800 MPU (CPU) uses 7 addressing modes to select operands, but with some added complications. All opcodes are 1 byte, and the opcode determines both the operation to take, and what operand to do it with; t...