Hi,

2011/9/10 Måns Rullgård <[email protected]>:
> "Ronald S. Bultje" <[email protected]> writes:
>> 2011/9/10 Måns Rullgård <[email protected]>:
>>> Luca Barbato <[email protected]> writes:
>>>
>>>> On 8/26/11 3:33 AM, Måns Rullgård wrote:
>>>>> "Ronald S. Bultje"<[email protected]>  writes:
>>>>>
>>>>>> From: "Ronald S. Bultje"<[email protected]>
>>>>>>
>>>>>>  From 52.503s (~40fps) to 27.973sec (~80fps) decoding of 480p sintel
>>>>>> trailer, i.e. a ~2x speedup overall, on a Nexus S.
>>>>>
>>>>> [...]
>>>>>
>>>>>> --- a/libavcodec/arm/asm.S
>>>>>> +++ b/libavcodec/arm/asm.S
>>>>>> @@ -97,6 +97,12 @@ T       add             \rn, \rn, \rm
>>>>>>   T       ldr             \rt, [\rn]
>>>>>>   .endm
>>>>>>
>>>>>> +.macro  ldr_dpren       rt,  rn,  rm:vararg
>>>>>> +A       ldr             \rt, [\rn, -\rm]
>>>>>> +T       sub             \rt, \rn, \rm
>>>>>> +T       ldr             \rt, [\rt]
>>>>>> +.endm
>>>>>> +
>>>>>>   .macro  ldr_post        rt,  rn,  rm:vararg
>>>>>>   A       ldr             \rt, [\rn], \rm
>>>>>>   T       ldr             \rt, [\rn]
>>>>>> @@ -133,6 +139,12 @@ T       ldrh            \rt, [\rn]
>>>>>>   T       add             \rn, \rn, \rm
>>>>>>   .endm
>>>>>>
>>>>>> +.macro  ldrb_post       rt,  rn,  rm
>>>>>> +A       ldrb            \rt, [\rn], \rm
>>>>>> +T       ldrb            \rt, [\rn]
>>>>>> +T       add             \rn, \rn, \rm
>>>>>> +.endm
>>>>>
>>>>> Those macro names are very badly chosen.
>>>>
>>>> ldrb_post seems in line with ldr_post. ldr_dpren named as ldr_dpre
>>>> seems equivalent to the other macros using sub. Which names you have
>>>> in mind?
>>>
>>> I'm still trying to figure what "dpren" is supposed to denote.
>>
>> d is used for negative, pre is increment index before access. The dpre
>> macro, however, still changes the argument, as if there were an
>> exclamation mark (ldr r0, [r1, r2]!), whereas I want to use them
>> without changing the pointer, so a "no change to pointer" is what the
>> n stands for.
>>
>> d pre n = dpren. Other naming suggestions are welcome.
>
> Names should indicate what things do, not what they do not do.

That's not a suggestion. If dpre is used for negative pre with change
to ptr, isn't dpren useful for negative pre without change to ptr?
.
Ronald
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