Re: [Qemu-devel] [patch] target-alpha: squashed fpu qualifiers patch

[Richard Henderson]

On 12/24/2009 07:18 AM, Aurelien Jarno wrote:
> My main concern about this patch is that I don't really understand why
> the current fp exceptions, the current rounding mode or flush_to_zero
> mode are stored in FP_STATUS. I think it would be better to have
> dedicated variable(s) in the cpu state structure, as it is done in other
> emulated architectures.

The internal format for these features is quite different (in terms of 
bit ordering) than the native Alpha format.  If I were to be forcing the 
bits back into the Alpha format after each operation, that would be far 
more shifting and masking than only doing the conversion to Alpha format 
when the FPCR register is read or written.  At present I'm only saving a 
value and ORing it back in

However, if you're convinced I should keep things in Alpha format all 
the time, I can rearrange the patch along those lines.


r~