Re: [hatari-devel] Bcc target address in debugger

[Christian Zietz <czietz@xxxxxxx>]

Eero Tamminen schrieb:
> Hi,
>
> On 29.8.2021 23.39, Miro Kropáček wrote:
> > I've been playing with Hatari's debugger for the past few days and I don't
> > get one thing. Why does it always show $0000000 as the target address? Like
> > this:
> >
> > CPU=$1889a, VBL=972, FrameCycles=565296, HBL=276, LineCycles=48, DSP=N/A
> > 0001889A 66fa                     BNE.B #$fa == $00000000 (T)
> >
> > There wasn't a single case where I'd see something else. The T/F indicator
> > works, the jump itself works, I just don't understand that that zero is
> > supposed to mean. Latest Hatari, nothing strange, just stepping the code.
>
> I think either Toni or Nicolas need to answer this...

Well.... It seems that the UAE disassembler uses 0xFFFFFFFF as a special
value to indicate whether a source or destination address is valid:
https://github.com/tonioni/WinUAE/blob/1e81c84ed109b945dce6bdbba10eda9da3e35d64/disasm.cpp#L1743
Hatari, however, for reasons unknown to me, initializes these variables
to 0 instead:
https://git.tuxfamily.org/hatari/hatari.git/tree/src/cpu/disasm.c#n1754
Unfortunately, when printing the target address, it checks for the
special value to decide which address to use and ends up using deaddr2
instead of seaddr2:
https://git.tuxfamily.org/hatari/hatari.git/tree/src/cpu/disasm.c#n2190

Regards
Christian
--
Christian Zietz  -  CHZ-Soft  -  czietz@xxxxxxx
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