Messages in this thread | | | Subject | Re: [tip:x86/asm] x86, bitops: Change bitops to be native operand size | From | Joe Perches <> | Date | Sun, 10 Nov 2013 18:22:50 -0800 |
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On Sun, 2013-11-10 at 18:06 -0800, H. Peter Anvin wrote: > On 11/10/2013 02:44 PM, Joe Perches wrote: > > On Sun, 2013-11-10 at 14:10 -0800, H. Peter Anvin wrote: > >> Yes, on the generic it is int. > >> The problem is in part that some architectures have bitop > >> instructions with specific behavior. > > I think that all bitop indices should be changed > > to unsigned (int or long, probably long) for all > > arches. > > Is there any impediment to that? > It is at the very best misleading. On x86 bit indicies will be signed > no matter what the data type says,
?
> and having an unsigned data type > being interpreted as signed seems like really dangerous. > On the other hand, for the generic implementation unsigned long makes sense. > We might need a bitindex_t or something like that for it to be clean.
Is there really any reason to introduce bitindex_t?
Perhaps the current x86 bitops asm code is being conflated with the ideal implementation?
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