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I need the definition of a function $s(v,p,w) = i$ where $v$ is an integer that can be expressed as binary or decimal, $p$ is the position of a bit in $v$, and $w$ is an amount of bit from 1 to $n$. The function return $i$, another integer that corresponds to the $w$'s bits at position $p$ in $v$.

Examples with $v = $ 0b1011 = 11

For $p = 0$ and $w = 1$, $f(11, 0, 1) = 1$

$f(11, p=1, w=1) = 1$

$f(11, p=0, w=2) = 3 = $ 0b11

$f(11, p=1, w=2) = 1 = $ 0b01

etc. (sorry for abusive notations).

this post partially answer by returning a given bit, but I also need the bit-width ads parameter.

Welgriv
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  • (v>>(p+w)) is the number after the range that you want. Then (v>>(p+w))<<(p+w) is that padded with zeros on the right. You can subtract v - (v>>(p+w))<<(p+w) to remove the first chunk from the left that is not needed. Finally, remove the chunk from the right (v - (v>>(p+w))<<(p+w))>>p. – plop Aug 23 '22 at 14:03

1 Answers1

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Just looking at your link, I think you can adapt the answer that way:

$$f(b,k,w)=\left\lfloor\frac{b}{2^k}\right\rfloor-2^w\left\lfloor\frac{b}{2^{k+w}}\right\rfloor$$

rambi
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