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Re: [PATCH v3 03/18] Add string-maskoff.h generic header
On 10/01/2018 21:24, Paul Eggert wrote:
> On 01/10/2018 04:47 AM, Adhemerval Zanella wrote:
>> +/* Create a mask with high bit of each byte being 1, and the low 7 bits
>> + being all the opposite of the input mask. It is used to mask off
>> + undesirable bits from an aligned read from an unaligned pointer,
>> + and also taking care to avoid match possible bytes meant to be
>> + matched. For instance, on a 64 bits machine with a pointer alignment
>> + of 3 the function returns 0x7f7f7f0000000000 (input meant to
>> + be 0xffffff0000000000) for BE and 0x00000000007f7f7f for LE (input
>> + meant to be 0x0000000000ffffff). */
>> +static inline op_t
>> +highbit_mask (op_t m)
>> +{
>> + return m & ~repeat_bytes (0x80);
>> +}
>
> The first line of the comment does not match the implementation, which would have to be something like "return (m ^ repeat_bytes (0x7f)) | repeat_bytes (0x80);" to match the comment. Also, I suggest replacing "~repeat_bytes (0x80)" with "repeat_bytes (0x7f)" as the latter is a bit simpler.
Thanks, I will change it locally.