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Re: DOS 3.3 File Manager calls - stomping on Track 0, sector 0



Michael J. Mahon wrote:
schmidtd wrote:

mmphosis wrote:

schmidtd wrote:

Does anyone know how to trap the I/O errors that happen when using this interface? Right now, it dumps me back into BASIC.


Yes.  Look at what "jmp error" is doing in the code.


Oh, right - I get that for the File Manager code.  That's what I get
for changing subjects without changing the subject line.

My problem now is: When I do the Ctrl-D BSAVE, if an error occurs - it
blows all the way back to BASIC, never giving control back to my
assembly.


That's a real functional deficit...

I wonder how many "error exits" there are...it would be handy if
all of them went through a single piece of code.

A glance at the DOS listing looks like good news!

It looks like all DOS errors go to $A6D2, with the error number
in the A register.  Patching a JMP in there should do the job,
or maybe an SEC; RTS, depending on how the normal return works.

(BTW, at least one version of Beneath Apple DOS has the ERROR entry
point listed erroneously as $A6D5.)

-michael

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