Saving machine code games to DeltaDOS disk?

A place to discuss everything Dragon related that doesn't fall into the other categories.
Post Reply
zephyr
Posts: 1474
Joined: Mon Jul 21, 2008 1:18 am

Saving machine code games to DeltaDOS disk?

Post by zephyr »

Most machine code programs (games) have an EXEC address which is different to the START address. A typical example is: START ADDRESS = $0C00, END ADDRESS = $7000, EXEC ADDRESS = $4000. The DeltaDOS manual states that the SAVEM command only accepts a START and END address (SAVEM"NAME",START,END). How do you save machine code programs (games) like this to DeltaDOS disk?
User avatar
robcfg
Posts: 1529
Joined: Sat Apr 04, 2009 10:16 pm
Location: Stockholm, Sweden
Contact:

Re: Saving machine code games to DeltaDOS disk?

Post by robcfg »

Maybe you could save the machine code with SAVEM "",START,END, and then run it with LOADM"":EXEC $4000.

Not ideal, but it may work.
zephyr
Posts: 1474
Joined: Mon Jul 21, 2008 1:18 am

Re: Saving machine code games to DeltaDOS disk?

Post by zephyr »

I had already thought about that rather obvious method. But then I thought about having to remember/write down all of the the different EXEC addresses for programs on several floppy disks. :lol:
Sarah
Posts: 177
Joined: Wed Apr 13, 2011 3:36 pm
Contact:

Re: Saving machine code games to DeltaDOS disk?

Post by Sarah »

Does the LOADM command update the EXEC vector ($009d:009e)?

If not, then I suppose there isn't much hope for a straightforward solution.

You could artificially make the files execute from their start address, if that would help.
sixxie
Posts: 1346
Joined: Fri Jul 18, 2008 8:36 am
Location: Hertfordshire
Contact:

Re: Saving machine code games to DeltaDOS disk?

Post by sixxie »

The manual says it'll only start things from the beginning of the binary. Goes so far as to recommend putting a JMP in as the first instruction...
zephyr
Posts: 1474
Joined: Mon Jul 21, 2008 1:18 am

Re: Saving machine code games to DeltaDOS disk?

Post by zephyr »

Sarah wrote:Does the LOADM command update the EXEC vector ($009d:009e)?
Yes.
zephyr
Posts: 1474
Joined: Mon Jul 21, 2008 1:18 am

Re: Saving machine code games to DeltaDOS disk?

Post by zephyr »

sixxie wrote:The manual says it'll only start things from the beginning of the binary. Goes so far as to recommend putting a JMP in as the first instruction...
The JMP idea would be an acceptable compromise for most programs. :)
Post Reply