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SvarDOS / edrdos

Enhanced DR-DOS kernel and command interpreter ported to JWasm and OpenWatcom C
http://svardos.org/
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Early kernel relocation of SvarDOS flavours is difficult to trace #107

Open ecm-pushbx opened 3 months ago

ecm-pushbx commented 3 months ago

The copywords function is used twice and the data that it copies seems to include itself in both cases. This is a problem when lDebug is used to trace/proceed, either with tp or p on the rep movsw or a p on the call copywords, as they will cause the copy to copy the int3 breakpoint to the destination rather than the original data.

My programs do a lot of relocation but I have seldom had problems like this yet. Fortunately with the debugger support enabled we can skip past the early relocation / depacking by running an lDebug g command.

boeckmann commented 3 months ago

The double copy is not actually needed on the uncompressed freedos load protocol. could be optimized by a single move. maybe I revisit this at a later time...

ecm-pushbx commented 3 months ago

You'll have to move backwards to directly move from 00600h to 00700h. And you need a small relocator stub to execute outside the kernel data.