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Author Topic: What does guru number 8000 0020 mean?  (Read 2816 times)

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Offline gazspTopic starter

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What does guru number 8000 0020 mean?
« on: February 13, 2007, 10:19:29 AM »
Any ideas anyone? Also, is there a guide to the Guru numbers on the net anywhere?

Thanks,
Gaz.
 

Offline Chain

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too lazy to use shift key properly...
 

Offline Piru

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Re: What does guru number 8000 0020 mean?
« Reply #2 on: February 13, 2007, 10:49:37 AM »
"trap #0" instruction executed.
 

Offline gazspTopic starter

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Re: What does guru number 8000 0020 mean?
« Reply #3 on: February 13, 2007, 01:21:11 PM »
What does it mean though? :-)
 

Offline gazspTopic starter

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Re: What does guru number 8000 0020 mean?
« Reply #4 on: February 13, 2007, 05:46:34 PM »
Let me put it another way.

This means that TRAP #0 has been executed by the processor, right? So why would this instruction occur in a game for example?

I'm trying to run a game on an 040 but I just get this guru every time it starts.

Thanks,
Gaz.
 

Offline motorollin

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Re: What does guru number 8000 0020 mean?
« Reply #5 on: February 13, 2007, 06:26:18 PM »
What game is it?

--
moto
Code: [Select]
10  IT\'S THE FINAL COUNTDOWN
20  FOR C = 1 TO 2
30     DA-NA-NAAAA-NAAAA DA-NA-NA-NA-NAAAA
40     DA-NA-NAAAA-NAAAA DA-NA-NA-NA-NA-NA-NAAAAA
50  NEXT C
60  NA-NA-NAAAA
70  NA-NA NA-NA-NA-NA-NAAAA NAAA-NAAAAAAAAAAA
80  GOTO 10
 

Offline Wol

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Re: What does guru number 8000 0020 mean?
« Reply #6 on: February 13, 2007, 06:29:27 PM »
@gazsp


Perhaps the 040 has found an Instruction it does not understand,
it does not have the full instruction set of 020 and 030's
or even plain old 68000.

It's possible the game has bee written for a lesser processer.

Make sure you have the latest 040.library installed on
you system, also try cyberpatcher or oxypathcer.


Wol.
Only after the last tree has been cut down,
Only after the last river has been poisoned,
Only after the last fish has been caught,
Only then will you find that money cannot be eaten.

--- Cree Indian prophecy ---
 

Offline Piru

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Re: What does guru number 8000 0020 mean?
« Reply #7 on: February 14, 2007, 05:26:07 AM »
@gazsp
Quote
This means that TRAP #0 has been executed by the processor, right?

Correct.
Quote
So why would this instruction occur in a game for example?

Typically old (A500 era) games would use this to get into supervisor mode. There's some nice exec/Supervisor call for that, but I guess the coders didn't know about it back then.

Quote
I'm trying to run a game on an 040 but I just get this guru every time it starts.

Most likely the game in question pokes vector table without knowlege about the vector base register (VBR). Basically it pokes the vector to wrong address and thus trap #0 will not give supervisor, but rather crash.

Enforcing the VBR back to address 0 might help (or booting without startup-sequence).

However, if the game is using trap #0 tricks, then it might also fail on anything higher than 68000 in general (abusing stackframes etc). In these cases the only way to run it is to use WHDLoad.
 

Offline Piru

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Re: What does guru number 8000 0020 mean?
« Reply #8 on: February 14, 2007, 05:28:15 AM »
@Wol
Quote
Perhaps the 040 has found an Instruction it does not understand

Trap #0 works just fine on 040.

Quote
Make sure you have the latest 040.library installed on you system, also try cyberpatcher or oxypathcer.

Actually it likely works better without 040 library (that is without setpatch).