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bochs debugger trace over
Posted: Mon Mar 01, 2004 11:24 pm
by firas981
In high level programming languages IDEs , usually there are two common debug commands :
1)trace into
2)trace over .
"trace over" is used to skip the getting into procedure code...
in bochs debugger we have "s" to simulate "trace into" , is there a way to simualte "trace over" , so jumping over "jmp" or "call" instructions
thanks
Re:bochs debugger trace over
Posted: Mon Mar 01, 2004 11:28 pm
by Candy
firas981 wrote:
In high level programming languages IDEs , usually there are two common debug commands :
1)trace into
2)trace over .
"trace over" is used to skip the getting into procedure code...
in bochs debugger we have "s" to simulate "trace into" , is there a way to simualte "trace over" , so jumping over "jmp" or "call" instructions
Set a breakpoint after the jmp/call (check for the size to the right of it, the bytes are listed) and continue. Note, known issue, doesn't always break. If you want to be sure, set a number of extra breakpoints at byte intervals after that too.
Re:bochs debugger trace over
Posted: Tue Mar 02, 2004 1:56 pm
by firas981
well , if i didn't mis understand you , yuo say that when returning from call or jmp to some breakpoint then the bochs debugger may not stop at this breakpoint.
yes , this what actually happened with me , although i followed your advice about putting several breakpoints .
is there a solution ?
thanks
Re:bochs debugger trace over
Posted: Wed Mar 03, 2004 3:18 am
by Candy
firas981 wrote:
yes , this what actually happened with me , although i followed your advice about putting several breakpoints .
Not that I know of. It's a bug in bochs debugger, and I've run into some others (only 9 or 10 breakpoints?).
Report it on the bochs bug DB and mark it as high as you can, then expect to not hear anything for half a year.
Or mail it to Christophe Bothamy at
[email protected] (not public email addy, remove all the spam and smpa words), who is a bochs developer.
Re:bochs debugger trace over
Posted: Wed Mar 03, 2004 11:56 am
by Candy
As an aside, bochs has more bugs
In debugging, when you look at a backward short jump (byte EB) it's followed by a signed byte. It's decoded unsigned by the decoder, but executed signed. All backward jumps look weird in disassemblies