Insertion
5.1 Insertion: You are given two 32-bit numbers, N and M, and two bit positions, i and j. Write a method to insert M into N such that M starts at bit j and ends at bit i. You can assume that the bits j through i have enough space to fit all of M. That is, if M = 10011, you can assume that there are at least 5 bits between j and i. You would not, for example, have j = 3 and i = 2, because M could not fully fit between bit 3 and bit 2.
EXAMPLE
Input: N 10000000000, M = 10011 i 2, j 6
Output: 10001001100
Brain storm:
- Manipulate vulnerable and preserved values
109 8 7 6 5 4 3 2 1 0
1 0 0 0 0 0 0 0 0 0 0 <-- N
1 1 1 1 0 0 0 0 0 1 1 mask <-- preserve outside using i and j
1 0 0 0 0 0 0 0 0 0 0 preserved <-- N & mask
1 0 0 1 1 0 0 <-- M + i nonpreserved states (i)
1 0 0 0 1 0 0 1 1 0 0 <-- (N & mask) & M + i = result
#include <iostream>
#include <string>