Re: [hatari-devel] 68030 MMU work

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Thanks for the hint. Obviously the root pointer register is not configured at the time you do the PTEST. For PTESTR vs. PTESTW: This was just a wrong debugging message. It actually worked the right way. I'll correct this.

Another problem i found: The invalid bit is not set in the status register ... i'll correct that one too.
The last problem: your instruction specifies searching the translation tables with function code 7. Normally function code 7 would cause a transparent translation. In normal operation, the translation tables are never searched using function code 7. Unfortunately there is no description in the datasheet on how this special case is handled. So i guess it just searches the tables ... even when FC is 7.

I've appended the patch to this message.

Attachment: mmu030_patch18.diff
Description: Binary data


Am 05.10.2012 um 09:30 schrieb Uwe Seimet:

> Hi,
> 
> it appears to me as if the PMMU opcodes are not yet correctly decoded.
> When executing this:
> 
>        lea $e00000,a0
>        ptestr #7,([8,a0]),#7,a0
> 
> Hatari reports
> 
> PTESTW 07,00E00000,#7,A1 PC=00411EDA
> CPU Root Pointer: 0000000000000000
> Fatal error: Root pointer is invalid descriptor!
> PTEST: 00E00000, fc = 7, level = 7, return descriptor to register A0
> PTEST status: 0000, B = 0, L = 0, S = 0, W = 0, I = 0, M = 0, T = 0, N = 0
> M68000 Bus Error writing at address $0.
> 
> ptestw and ptestr seem to be confused here?
> 
> Take care
> 
> Uwe
> 
> 



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