Re: [Qemu-devel] [PATCH v2] bitops.h: Add field32() and field64() functions to extract bitfields

[Peter Maydell]

On 27 June 2012 14:15, Avi Kivity <address@hidden> wrote:
> I suggest adding the analogous functions for writing.  I believe the
> common naming is extract/deposit.
>
> static inline uint64_t deposit64(uint64_t *pvalue, unsigned start,
>                                 unsigned length, uint64_t fieldval)
> {
>    uint64_t mask = (((uint64_t)1 << length) - 1) << start;
>    *pvalue = (*pvalue & ~mask) | ((fieldval << start) & mask);
> }
>
> Useful for setting a bit to a specific value.

Do you have a use case in mind for this one?

-- PMM