Fun and games with the 68000!

h0ffman · 27 February 2011, 17:14

So, basically, I've been making this music disk. Most of the dev has been done in my WinUAE A1200 setup. Simple basic setup, 2 meg chip, 8 meg fast, 68020, the kinda platform you'd expect to have at home

Worried I had overloaded each frame with the scope, scroller, etc. etc. I start testing it on an A600 setup today and it's been.. very testing.

First I finally replaced the loader, thinking that was causing an issue (needed to be done anyhow so no bother there).

With loader replaced, I test again, crash... after hours of digging I finally find the CrunchMania source has a BLE.L in it!! Simply remove the .L and everything gets a little further...

The next issue is a weird one. There is a comparison I do from one module to the next which is...

cmpm.l (a0)+,(a2)+
bne.b ML_NoMatch

Finally found the issue. In some instanced this hits an odd address in A0. Now on the 68020 or 68010, not a problem, goes straight through it without any questions. But the 68000 takes expection to this.

Just thought I'd share

now time for another test.

kriz · 27 February 2011, 22:55

Keep on the work man

phx · 28 February 2011, 15:44

Quote:

Originally Posted by h0ffman

With loader replaced, I test again, crash... after hours of digging I finally find the CrunchMania source has a BLE.L in it!! Simply remove the .L and everything gets a little further...

Tell the assembler to generate 68000 output. Then it should either warn about such instructions or convert it into BLE.W.

Quote:

Finally found the issue. In some instanced this hits an odd address in A0. Now on the 68020 or 68010, not a problem, goes straight through it without any questions. But the 68000 takes expection to this.

Yes, the 68020+ can handle unaligned accesses but with a speed penalty. The 68010 though, should behave like the 68000. In any case unaligned accesses should be avoided.

h0ffman · 28 February 2011, 16:53

Oh god yeah! Managed to crash my scope multiple times today by looking at my look up table on odd addresses..

I love amiga programming!

StingRay · 28 February 2011, 16:54

Quote:

Originally Posted by h0ffman

Oh god yeah! Managed to crash my scope multiple times today by looking at my look up table on odd addresses..

CNOP 0,2 is your friend.

27 February 2011, 17:14	#1
h0ffman Registered User Join Date: Aug 2008 Location: Salisbury Posts: 744	Fun and games with the 68000! So, basically, I've been making this music disk. Most of the dev has been done in my WinUAE A1200 setup. Simple basic setup, 2 meg chip, 8 meg fast, 68020, the kinda platform you'd expect to have at home Worried I had overloaded each frame with the scope, scroller, etc. etc. I start testing it on an A600 setup today and it's been.. very testing. First I finally replaced the loader, thinking that was causing an issue (needed to be done anyhow so no bother there). With loader replaced, I test again, crash... after hours of digging I finally find the CrunchMania source has a BLE.L in it!! Simply remove the .L and everything gets a little further... The next issue is a weird one. There is a comparison I do from one module to the next which is... cmpm.l (a0)+,(a2)+ bne.b ML_NoMatch Finally found the issue. In some instanced this hits an odd address in A0. Now on the 68020 or 68010, not a problem, goes straight through it without any questions. But the 68000 takes expection to this. Just thought I'd share now time for another test.

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27 February 2011, 22:55	#2
kriz Junior Member Join Date: Sep 2001 Location: No(R)Way Age: 41 Posts: 3,185	Keep on the work man

28 February 2011, 16:53	#4
h0ffman Registered User Join Date: Aug 2008 Location: Salisbury Posts: 744	Oh god yeah! Managed to crash my scope multiple times today by looking at my look up table on odd addresses.. I love amiga programming!

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