no of bit - variable

''what is k doing here? or in the other loop''

May be i should explain the background. The user can enter number of input and output in the range of 2 to 64 maximum. So the total number of input will be divided to 8 bits block by block. This is the function of k(8 loop maximum).

''this assignment has different widths ?''

The out_reg has 8 bits. however the number of bits assign to out_reg is depends on the formula.

for example

total number of input is 12 bits.

so, out_reg[0] has 8 bit(MSB)

then the remaining of 4 bits will be the LSB of out_reg[1](out_reg[1] has 8 bits too_