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SubjectRe: [tip:core/types] bitops: Add sign_extend8(), 16 and 64 functions
On 02/04/2015 11:17 PM, Ingo Molnar wrote:
>>>
>>> Even for the 8bit ones? Since we have the *H and *L register
>>> we have more 8 bit regs than we have 16/32 bit regs and it
>>> might just be worth it.
>>
>> Fewer, actually. gcc doesn't really use the H registers much,
>
> Is that true for other compilers as well?
>

Probably. It wrecks havoc on register allocation, and it doesn't buy
that much, especially on 64 bits where all the registers can be used for
8-bit operations.

-hpa



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