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86Box setup (Users)

posted by ecm Homepage E-mail, Düsseldorf, Germany, 04.02.2024, 22:01

> For completeness: FDISK also hangs in LBA mode when running under the EDR
> kernel.
>
> I will try to debug the INT 13 call FDISK does with ldebug, by setting a
> breakpoint to C800:145B.
If it is ROM you will not be able to set a breakpoint. However, you can set a breakpoint in a RAM handler such as the DOS's int 13h handler then step into the ROM.

FD Debug and lDebug do allow to trace ROMs somewhat but you can't use int3 style breakpoints in a ROM. If you trace an interrupt instruction with Trace Mode zero (do not trace into the handler) then rather than write a breakpoint, the debugger will set the Trace Flag as for an ordinary instruction then run the int. This will usually cause a Trace Interrupt one instruction too late, as the iret of the handler will act like an iret done by the debugger. This bit is done here: https://hg.pushbx.org/ecm/ldebug/file/156a4890666e/source/run.asm#l3911

lDebug does allow to trace repeatedly into the silent buffer until a user-specified condition is true, though. This can be used as a poor woman's replacement for commands like GT, GNT, or P (on a loop/call) that would require a breakpoint. Just TP cccccc WHILE csip != F000_1234+3 SILENT 1 will do for a very simple example. More complicated things are possible, eg the PR (Proceed Until Return) command replacement I described in https://pushbx.org/ecm/dokuwiki/blog/pushbx/2023/0...g_and_access_variables_recent_changes_to_ldebug

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l

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