Bad LEA instruction crashes DOSBox \ VOGONS

Bad LEA instruction crashes DOSBox

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First post, by peterferrie

Posted on 2010-12-09, 22:59

peterferrie Offline

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CASE_W(0x8d)
...
*rmrw=(Bit16u)(*EATable[rm])();

If rm contains an illegal value (for whatever reason), then DOSBox crashes.
The illegal EA entries should probably be set to call int6 or exit or something, not contain null.

Reply 1 of 4, by wd

Posted on 2010-12-09, 23:37

wd Offline

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What uses that?

Reply 2 of 4, by h-a-l-9000

Posted on 2010-12-09, 23:41

h-a-l-9000 Offline

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Would you like DOSBox to crash when the user inputs an illegal command? 😀

1+1=10

Reply 3 of 4, by peterferrie

Posted on 2010-12-10, 03:00

peterferrie Offline

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The emulated code should not be able to crash DOSBox. :-)
It's not used intentionally as far as I know (though someone might use it for anti-debug), but a bad copy of Lychnis demonstrated the behaviour.

Reply 4 of 4, by wd

Posted on 2010-12-10, 09:50

wd Offline

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The emulated code should not be able to crash DOSBox. 😀

Harekiet's comments in the code suggest otherwise.

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