Question

I have two 32 bit integers HI & LO, and I need to right shift bits in them, so that last last bit of HI becomes most significant bit of LO. In other words, shifting operation should work, as if two bits is a single 64bit unit. Language C/C++
Thanks !

Answer 1

This code below right-shifts 1-bit as you described.

It works by masking off all except the lowest bit in hi, and shifting it all the way left (Most Significant Bit), and joining that with lo shifted right one-bit.

Then, it simply shifts hi to the right one bit.

{
    lo = ((hi & 0x00000001)<<31) | (lo >> 1);
    hi = hi >> 1;
}