Re: [hatari-devel] Sokoban VGA (Falcon)

[Thomas Huth <th.huth@xxxxxx>]

Am Mon, 07 Oct 2013 00:35:32 +0200
schrieb Laurent Sallafranque <laurent.sallafranque@xxxxxxx>:

> Hi,
> 
> I've given a quick look at Sokoban (Falcon), and I get the following
> error:

Is that game freely available for download somewhere?

> Exception 2 (e12bcc) at e12bce -> e00fb6!

That's an bus error... can you determine where it comes from (e.g. by
putting a breakpoint with gdb and do a backtrace when it triggers?).

> The executed code before the error is a linea #7 (Bit block transfer)
> And the program stops on the TAS instruction.
> 
> I suspect the TAS instruction not to return to the correct PC
> address, but I haven't digged more for now (maybe there's a patch of
> this instruction in winuae, or in the old cpu).

I hardly believe that TAS itself is wrong (although the code for the
cycle-exact 68000 mode seems to be dodgy, but that does not matter here
since you run in 68030 mode instead).
The code you've added below seems to try to start the blitter. So I
think the problem could be related to the blitter instead.
Could you do a "info blitter" in the debugger when you reach the TAS
instruction?

> The last instructions before the crash
> 
> 
> $06aac6 : a007                                 linea 
> #7                        ; Bit block transfer
[...]
> $e12bcc : 4ad5                                 tas       (a5)
> Debugger: *CPU breakpoint*
>  >
>  > r
>    D0 0000007E   D1 00000004   D2 00000000   D3 FFFF0000
>    D4 00000001   D5 00000000   D6 00000000   D7 000080C0
>    A0 002DEA41   A1 00FF9841   A2 00000002   A3 00000002
>    A4 00000000   A5 00FF8A3C   A6 00083E02   A7 00087768

A5 = 0xff8a3c is the blitter control register ... TAS is obviously used
to test whether it is already running and to start it if it was not
running yet.

 Thomas