[hatari-devel] b help question (HBL $0)

Nicolas Pomarède npomarede at corp.free.fr
Wed Jun 1 00:05:38 CEST 2011


Le 31/05/2011 23:26, Eero Tamminen a écrit :
> Hi,
>
> On keskiviikko 01 kesäkuu 2011, Laurent Sallafranque wrote:
>> When I enter b help in the debug console, I get all the help for
>> breakpoint.
>>
>> I can read the following :
>>
>> ...
>>    Valid Hatari variable names (and their current values) are:
>>     - AesOpcode ($ffff), by default FFFF
>>     - BiosOpcode ($ffff), by default FFFF
>>     - FrameCycles ($44)
>>     - GemdosOpcode ($ffff), by default FFFF
>>     - HBL ($0)
>>     - LineAOpcode ($ffff), by default FFFF
>>     - LineCycles ($44), is always divisable by 4
>> ...
>>
>>
>> Is it really $0 for HBL ?
>> I think not.
>
> It's the value of the Hatari internal "nHBL" variable.
>
> If you've entered the debugger by pressing Altgr+Pause shortcut key,
> that's processed only in Video_InterruptHandler_VBL():
> ---
>          /* Start VBL, HBL and Timer B interrupts (this must be done after
> resetting
>           * video cycle counter setting default freq values in
> Video_ClearOnVBL) */
>          Video_StartInterrupts(PendingCyclesOver);
>
>          /* Act on shortcut keys */
>          ShortCut_ActKey();
> ---
>
> If you check HBL at some other point, e.g. after entering debugger due
> to some breakpoint, HBL has different values.

That's true ; framecycle is $44, so yes, this means the shifter is on hbl 0.

Nicolas



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