Wouldn't this fail (logic error) if s - y is less than -128 or greater than 127? Because sometimes the needed copmlement is not in the i8 range. So then the indexing would confuse it with another complement value that is inisde the i8 range. If so, it could be fixed by a simple bounds check on x and a continue if it is out of bounds.

devagya, please use spoiler flag next time.

It can be, but plenty of compilers will optimize a divide-by-two into a shift anyway. (Specifically any divide-by-power-of-two can be turned into a single shift)

Yes, bit operating is faster

Same :D

Given that the task is very specific I'd say it is, as it is performant and the code is readable.

If you had to, for example, generate neighbors up to a variable distance n received as a parameter of the function, that would be a different story.

return the count

Do I have to return a table as the example shows?

The usual wording in math problems like this would be "non-negative". The description could either make an exception for 0, or just change "positive" to "non-negative" and give a clear example.

0 is neither positive or negative, so...

0 just can't be positive in standard math, so it has to be reworded somehow instead.

NASM Translation

Wonder if this is really a best practice, although it completely satisfies the task... Well done.