Re: [Qemu-devel] Re: [PATCH v3 2/7] wdt_ib700: Don't use SoftFloat int64 type

[Blue Swirl]

On Sun, Dec 19, 2010 at 2:28 PM, Andreas Färber <address@hidden> wrote:
> Am 19.12.2010 um 15:16 schrieb Richard W.M. Jones:
>
>> On Sun, Dec 19, 2010 at 01:51:22PM +0100, Andreas Färber wrote:
>>>
>>> Am 18.12.2010 um 17:47 schrieb Richard W.M. Jones:
>>>
>>>> On Sat, Dec 18, 2010 at 05:25:26PM +0100, Andreas Färber wrote:
>>>>>
>>>>> softfloat.h's int64 type has least-width semantics,
>>>>> but this doesn't seem intended here, so use plain int64_t.
>>>>>
>>>>> v3:
>>>>> * Split off.
>>>>>
>>>>> Cc: Richard W.M. Jones <address@hidden>
>>>>> Signed-off-by: Andreas Färber <address@hidden>
>>>>> ---
>>>>> hw/wdt_ib700.c |    2 +-
>>>>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>>>>
>>>>> diff --git a/hw/wdt_ib700.c b/hw/wdt_ib700.c
>>>>> index b6235eb..1248464 100644
>>>>> --- a/hw/wdt_ib700.c
>>>>> +++ b/hw/wdt_ib700.c
>>>>> @@ -53,7 +53,7 @@ static void ib700_write_enable_reg(void *vp,
>>>>> uint32_t addr, uint32_t data)
>>>>>     30, 28, 26, 24, 22, 20, 18, 16,
>>>>>     14, 12, 10,  8,  6,  4,  2,  0
>>>>>  };
>>>>> -    int64 timeout;
>>>>> +    int64_t timeout;
>>>>>
>>>>>  ib700_debug("addr = %x, data = %x\n", addr, data);
>>>>
>>>> The use of int64(_t) was just so that the timeout calculation in the
>>>> next two lines would not overflow:
>>>>
>>>> timeout = (int64_t) time_map[data & 0xF] * get_ticks_per_sec();
>>>> qemu_mod_timer(s->timer, qemu_get_clock (vm_clock) + timeout);
>>>>
>>>> and from you say it does seem like it was a mistake to use int64
>>>> instead of int64_t.
>>>
>>> int64_t should be the right choice then.
>>>
>>>> ACK.
>>>>
>>>> In more general terms, am I doing the timeout correctly in this code?
>>>
>>> Being unfamiliar with both the timer code and this device, hard to
>>> say for me.
>>> You're taking the lower nibble of uint32_t data and indexing
>>> time_map[] with it, which contains 16 elements, so okay, upcast it
>>> to 64-bit and multiply it to ticks. Assuming that vm_clock works in
>>> ticks, adding the calculated timeout for the next expiry technically
>>> looks good. Except for the extra space. ;)
>>>
>>> Care to provide a formal Reviewed-by or Acked-by? I'd respin it for
>>> Blue with updated description.
>>
>> Is it enough just to write this:
>>
>> Reviewed-by: Richard W.M. Jones <address@hidden>
>> Acked-by: Richard W.M. Jones <address@hidden>
>>
>> or do you want me to send the updated patch with this added?
>
> Thanks, that's sufficient! I think of Acked-by as a superset of Reviewed-by
> so I'll go with the former.

No, Acked-by tag does not mean much but Reviewed-by carries a lot of weight:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/SubmittingPatches;h=689e2371095cc5dfea9927120009341f369159aa;hb=HEAD#l423