Re: [Qemu-devel] [PATCH v4] bitops.h: Add functions to extract and deposit bitfields

[Lluís Vilanova]

Peter Maydell writes:
[...] 
> +/**
> + * extract32:
> + * @value: the value to extract the bit field from
> + * @start: the lowest bit in the bit field (numbered from 0)
> + * @length: the length of the bit field
> + *
> + * Extract from the 32 bit input @value the bit field specified by the
> + * @start and @length parameters, and return it. The bit field must
> + * lie entirely within the 32 bit word. It is valid to request that
> + * all 32 bits are returned (ie @length 32 and @start 0).
> + *
> + * Returns: the value of the bit field extracted from the input value.
> + */
> +static inline uint32_t extract32(uint32_t value, int start, int length)
> +{
> +    assert(start >= 0 && length > 0 && length <= 32 - start);
> +    return (value >> start) & (~0U >> (32 - length));
> +}
[...]

Wouldn't it be better to use "unsigned int" instead on all the "start" and
"length" arguments?


Lluis

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