[Coco] Coco3 Memory Map?

Robert Gault robert.gault at worldnet.att.net
Wed Dec 1 08:00:12 EST 2004

David wrote:
> Hi all,
> I'm puzzling my way through TRS-80 Assembly Language Programming (W. Barden
> Jnr.)..
> It's primarilly aimed at the Coco2, although I'm trying to write for the
> Coco3
> All of the examples in the book use edtasm+, and assemble the object to
> start at $3F00 in memory
> In a 128k Coco3, should I be using a different execution address? will $3F00
> conflict with anything in disk basic, or..?
> Does anyone have a memory map of what space I can use for user programs
> whilst keeping the BASIC rom routines available for use?
> Can I end any more sentences with a question mark?
> Regards and thanks!
> David R
> (Australian.. sue me :P )

You can use any address you please depending on your purposes. If you 
want something to run while EDTASM+ is loaded so you can monitor it with 
ZBUG, enter O at the EDTASM prompt and you will be told where free 
memory starts. Your ORG statement can be that or higher as long as you 
don't overlap the ROM code at $8000.

If you want to create a program that LOADMs from Basic, you can have an 
ORG that is almost anywhere in memory between $00 and $8000. If you 
don't care whether you keep the Basic ROMs intact, your program can 
reside anywhere in memory as long as it does not overlap the hardware 
registers, $FF00 and up.

Read the EDTASM+ manual carefully. There are detailed charts explaining 
memory usage.

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