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[Qemu-devel] Re: 452efb didn't show up in the list
From: |
Artyom Tarasenko |
Subject: |
[Qemu-devel] Re: 452efb didn't show up in the list |
Date: |
Fri, 2 Apr 2010 22:32:26 +0200 |
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/