Re: [hatari-devel] FPU disassembly fault

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 09/11/2014 19:48, Douglas Little a écrit :
> I noticed a fault in disassembly today.
>
>
> Here's the assembly input code I was testing:
>
> *fmove.lfp7,d0*
> fsub.ld0,fp7
>
> And here is what is actually disassembling (and executing!). Note the
> fmove operand order...
>
>
> *$0354a6 : f200 6380                            fmove.l   d0,fp7*
> $0354aa : f200 43a8                            fsub.l    d0,fp7
>
>
> At first I thought it was the assembler, but the opcode encoding is
> correct, and disassembly is incorrect. It does seem to execute the
> correct instruction though.

Hi

With "--disasm uae" option, I get  this :

FPP.L #$6380,D0		which is not very useful

With next winuae cpu core, I get this :

f200 6380                FMOVE.L FP0,D0
f200 43a8                FSUB.L D0,FP7

So, as the "uae" disasembler use the same routine as the opcode 
decoding, it's normal that you get the same correct result.

But are you sure of your exemple ? you wrote "fp7,d0", but it seems it's 
fp0 if you give 6380.

I think this is an error with the external disassembler "--disasm ext", 
I will look into it, but it's harmless wrt emulation.

Nicolas