Re: [patch][rfa] SID --trace-semantics output

[Dave Brolley <brolley@redhat.com>]

Frank Ch. Eigler wrote:

>brolley wrote:
>
>  
>
>>A client of ours, for whom we're developing a SID port, requested
>>that SID's semantic trace show the actual value stored, accounting
>>for read-only fields and other side effects, rather than showing the
>>value which was attempted to be stored. [...]
>>    
>>
>
>Especially for bits outside the CPU, this has the potential to
>mislead, in that the disassembly trace would not represent the actions
>of the CPU.
>
but it would represent the actual result of the operation, which is what 
they want. Makes sense to me too, FWIW.

>>I eventually came up with the notion that the write/set methods of
>>SID's busses, control registers, memory access methods and hardware
>>write handers could return the actual value written. [...]
>>    
>>
>
>I am quite unfond of this approach.  It is a messy and limited way of
>providing just one more level of tracing.  Have you considered instead
>of all this the addition of tracing flags in the various devices that
>thusly mutilate their data?  That way, when they detect an incoming
>write (from whatever source), they can print the final afterimage.
>With carefully arranged tracing code in cgen_cpu, the additional
>messages from those peripherals could appear properly intermingled.
>  
>
This idea sounds reasonable and more in line with the SID architecture. 
I should have asked before I leaped :-)

Thanks,
Dave