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Index > DOS > Bug in the DOS interface "MODES.INC"?

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MCD



Joined: 21 Aug 2004
Posts: 604
Location: Germany
MCD
May it be that there is a bug in the DOS interface for Fasm? It is just a tiny thing, but I guess that this might cause troubles someday.

I mean, the IDT and GDT defined in "MODES.INC" should be aligned on a 8byte boundary, because the LGDT and LIDT instructions need GDTR and IDTR values aligned on QWORD.

This caused problems with another self coded PM program by me, but it doesn't seem to cause any harm to Fasm DOS.

Perhaps I'm wrong, I'm not sure.

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Post 23 Dec 2004, 15:49
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Matrix



Joined: 04 Sep 2004
Posts: 1171
Location: Overflow
Matrix
hmm,
it never hurts to align these kind of stuff ...
you can prefer aligning your core functions too, it can speed up things a bit.
Post 24 Dec 2004, 00:04
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MCD



Joined: 21 Aug 2004
Posts: 604
Location: Germany
MCD
I meant to remembered that somewhere in the Intel documentation you can read that descriptor tables should be aligned on 8 byte boundary. I don't guess that this would affect Fasms speed, rather it's safety?
Post 25 Dec 2004, 18:40
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