[Qemu-devel] Re: 452efb didn't show up in the list

[Artyom Tarasenko]

2010/4/2 Blue Swirl <address@hidden>:
> On 4/1/10, Artyom Tarasenko <address@hidden> wrote:
>> 2010/4/1 Blue Swirl <address@hidden>:
>>  > Which list?
>>
>>  This mailing list?
>>
>>
>>  > On 4/1/10, Artyom Tarasenko <address@hidden> wrote:
>>  >> and looks wrong or incomplete to me:
>>  >>
>>  >>  >According to Sun4M System Architecture Manual chapter 5.3.2, a limit
>>  >>  >of 0 will not generate interrupts.
>>  >>
>>  >>  This is indeed correct, but the chapter 5.3.2 also explains why:
>>  >>
>>  >>  "Setting the limit register to  0  allows the counter to free run. 
>> Since the
>>  >>  timer always resets to a value of 500 nS after reaching maximum count,
>>  >>  there is no match and no interrupts are generated."
>>  >>
>>  >>  The part about 500 nS (0x00000200 in the counter register) and
>>  >>  no match seems to be not addressed.
>>  >
>>  > The 500ns offset part could be addressed by making the timer period
>>  > shorter by 1 tick. I doubt such a change would have any visible
>>  > difference with QEMU, except that tick count of 0 should never appear
>>  > in the counter but it may now.
>>
>>
>> as well as all the other values between 0 and 0x200. But it's less
>>  important I guess.
>>
>>
>>  > For the no match part, t->reached should not be set if t->limit == 0.
>
> I think this patch would do what is expected.

Looks good and passes my tests, thanks.

Redefining LIMIT_TO_PERIODS is a really nice solution.


-- 
Regards,
Artyom Tarasenko

solaris/sparc32 under qemu blog: http://tyom.blogspot.com/