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dosemu2 / fdpp

FreeDOS plus-plus, 64bit DOS
GNU General Public License v3.0
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FCB (int 21h func 29h): should keep parsing name even if drive letter invalid #200

Closed tkchia closed 2 years ago

tkchia commented 2 years ago

On both MS-DOS 2.11 and MS-DOS 5.0, the "parse filename to FCB" syscall (int 0x21, function 0x29), when it encounters an invalid drive letter, will still continue parsing the file name, and return with al = 0xff and ds:si pointing after the parsed file name.

E.g. given an input like z:foo.bar,baz — assuming z is not a valid drive letter — the syscall will return al = 0xff and ds:si pointing at the comma.

FreeDOS++ should probably do likewise. I have already submitted a proposed patch to the upstream FreeDOS kernel project, at https://github.com/FDOS/kernel/pull/82 .

(Edit: I also submitted another patch upstream at https://github.com/FDOS/kernel/pull/83 which fixes a problem in my earlier patch.)

Thank you!

stsp commented 2 years ago

Andrew, do I remember correctly that we already did that?

andrewbird commented 2 years ago

Your memory must be better than mine, I have no recollection of this topic. Perhaps I should write a test to see what the other DOSes do.

stsp commented 2 years ago

But I suppose @tkchia already has such test?

andrewbird commented 2 years ago

Yes I guess that's true.

tkchia commented 2 years ago

Hello @stsp, hello @andrewbird,

I am currently working on such a test, in a separate tkchia/makefcb branch in my libi86 project.

See e.g. commit https://github.com/tkchia/libi86/commit/46dbd514d26e3ea124eac9dce3452b93a68a8596 : this commit adds a new _makefcb (...) function to libi86, and also adds a test case for it.

(The parts of the test that check for the correct behaviour are currently disabled with #if 0, since otherwise the test currently fails, at least on my system...)

Thank you!

tkchia commented 2 years ago

Hello @stsp, hello @andrewbird,

The test code for this particular behaviour for int 0x21, ah = 0x29, is now in my libi86 master branch — though the test is disabled for now. Let me know if you would like me to enable the test. Thank you!

stsp commented 2 years ago

Ping. Andrew, have you looked at a test?

stsp commented 2 years ago

@tkchia maybe you can just check fdpp yourself and submit a patch if needed?

tkchia commented 2 years ago

Hello @stsp,

@tkchia maybe you can just check fdpp yourself and submit a patch if needed?

Hmm... let me look into doing that. Thank you!