[hatari-devel] Perhaps this evocate something to you...

[Nicolas Pomarède]

Le 19/01/2011 23:55, Laurent Sallafranque a écrit :
>  > What do you means by "it bugs" ? Crash ? Bomb ? Bad visual result ?
>
> At 16 Mhz, it freezes at the following instructions after the 1rst
> screen is rendered :
>
> 00030020 082e 0000 0002 BTST.B #$0000,(A6, $0002) == $ffffa202
> 00030026 67f8 BEQ.B #$fffffffffffffff8 == $00030020 (T)

You mean these 2 instructions are looping forever ?
It would mean ISR receive reg is always empty, so I think you would need 
to see the corresponding DSP code being executed to see what it's 
supposed to send back, the 68030 code alone won't help.


> Whereas at 32 Mhz, the animation continues to play correctly.
>
> It looks like a DSP synchro.
>
> This is a kind of tridi screen with letter morphing from W to A to T to
> E ...
>
> WATERSHIP.
>
> Regards
>
> Laurent
>
>
>
> Le 19/01/2011 23:50, Nicolas Pomarède a écrit :
>> Le 19/01/2011 23:37, Laurent Sallafranque a écrit :
>>> A good candidate for testing 16Mhz vs 32 Mhz is Watership.
>>>
>>> It loads quickly and bugs immediately at 16 Mhz (but runs at 32Mhz).
>>>
>>> I've taken 2 CPU traces : one at 16 Mzh and one at 32 Mhz and I've made
>>> a diff of the 2 traces.
>>>
>>> Here is the result :
>>>
>>> The 2 programs are running the first 3196 instructions the same way.
>>> Here are the latest instructions ran by both tests :
>>>
>>> ...
>>> 0002E226 4298 CLR.L (A0)+
>>> 0002E228 51c9 fffc DBF .W D1,#$fffc == $0002E226 (F)
>>> 0002E226 4298 CLR.L (A0)+
>>> 0002E228 51c9 fffc DBF .W D1,#$fffc == $0002E226 (F)
>>> 0002E226 4298 CLR.L (A0)+
>>> 0002E228 51c9 fffc DBF .W D1,#$fffc == $0002E226 (F)
>>> 0002E226 4298 CLR.L (A0)+
>>>
>>> At line 3197, the 32 Mhz test continues to run the same 2 instructions
>>> as above.
>>>
>>> But the 16 Mhz test does :
>>>
>>> 00E03C50 52b9 0000 04ba ADD.L #$00000001,$000004ba
>>> 00E03C56 e7f9 0000 11ba ROLW.W $000011ba
>>> 00E03C5C 6a48 BPL.B #$00000048 == $00E03CA6 (F)
>>> 00E03C5E 48e7 fffe MOVEM.L D0-D7/A0-A6,-(A7)
>>> 00E03C62 614a BSR.B #$0000004a == $00E03CAE
>>> 00E03CAE 48e7 c080 MOVEM.L D0-D1/A0,-(A7)
>>> 00E03CB2 2038 11bc MOVE.L $000011bc,D0
>>> 00E03CB6 677a BEQ.B #$0000007a == $00E03D32 (T)
>>> 00E03D32 4cdf 0103 MOVEM.L (A7)+,D0-D1/A0
>>> 00E03D36 4e75 RTS.L
>>> 00E03C64 0838 0001 0484 BTST.B #$0001,$00000484
>>> 00E03C6A 672a BEQ.B #$0000002a == $00E03C96 (F)
>>> 00E03C6C 4a38 11b1 TST.B $000011b1
>>> 00E03C70 6724 BEQ.B #$00000024 == $00E03C96 (T)
>>> 00E03C96 3f38 0442 MOVE.W $00000442,-(A7)
>>> 00E03C9A 2078 0400 MOVEA.L $00000400,A0
>>> ...
>>>
>>>
>>> At line 4653, the 32 Mhz test does :
>>>
>>> 0002E228 51c9 fffc DBF .W D1,#$fffc == $0002E226 (F)
>>> 00E03C50 52b9 0000 04ba ADD.L #$00000001,$000004ba
>>> 00E03C56 e7f9 0000 11ba ROLW.W $000011ba
>>> 00E03C5C 6a48 BPL.B #$00000048 == $00E03CA6 (T)
>>> 00E03CA6 11fc 00df fa11 MOVE.B #$df,$fffffa11
>>> 00E03CAC 4e73 RTE.L
>>> 0002E226 4298 CLR.L (A0)+
>>> 0002E228 51c9 fffc DBF .W D1,#$fffc == $0002E226 (F)
>>> 0002E226 4298 CLR.L (A0)+
>>> 0002E228 51c9 fffc DBF .W D1,#$fffc == $0002E226 (F)
>>> 0002E226 4298 CLR.L (A0)+
>>> 0002E228 51c9 fffc DBF .W D1,#$fffc == $0002E226 (F)
>>>
>>>
>>> Both tests are jumping to address $E03C50, but not after the same amount
>>> of instructions.
>>>
>>
>> Well, the tests are not exactly jumping, they are interrupted by an
>> MFP interrupt, which points in the ROM to e03c50.
>>
>> $4BA is "Raw 200Hz timer", so this is just an interrupt that counts
>> 200 Hz pulses.
>>
>>> The test after the first 3 instructions after the "interrupt" is TRUE
>>> for the 32 Mzh test, but is false for the 16 Mhz test.
>>>
>>> The 32 Mhz test continues to CLR / DBF whereas the 16 Mhz test goes into
>>> completely different code.
>>
>> At one point, it's normal 32 and 16 Mhz don't return at the same
>> place, because the 32 Mhz version is running twice more instructions
>> per cycle, so when it's interrupted by the 200 Hz timer, it processed
>> more instruction than when it ran at 16 Mhz.
>>
>> What do you means by "it bugs" ? Crash ? Bomb ? Bad visual result ?
>>
>>
>> Nicolas
>>
>>
>