Re: Likely opcode execution bug

Hi,

22.08.2021 18:19, Volker Ruppert:
>> mov dword ptr cs:[si+3], 0x0104d041
>
> Please verify the behavior of this instruction with the latest Bochs
> version 2.7.

Done. With 2.7 it behaves the same as with 2.6.11.

I just thought it might have to do with the fact that the code is being 
executed in F000:xxxx area, and the above "mov" instruction also 
operates on address from that range. Of course this is set up as 
writable shadow ROM memory, otherwise the code in question would not 
work at all. But still maybe some underlying implementation of memory 
operation is unhappy about such setup and behaves incorrectly.

Here is a memory fragment showing the appearance of 1 normal and 
following 3 additional bogus copies of this dword, with "dots" 
representing unchanged bytes:

F90B0: .. .. .. .. .. .. .. .. .. 41 D0 04 01 .. 41 D0
F90C0: 04 01 .. 41 D0 04 01 .. 41 D0 04 01 .. .. .. ..


Thank you,

Regards,
Nikolai

>
> --
> Thanks,
> Volker
>