How does bitshift work?

bitshift(56,-1)

gives answer 28 in matlab

My understanding of this working is as follows:

the function converts 56 to binary value ie 0101 0110 and does right shift since its -1

so 0010 1011 -> 2b (hexa)

so the answer should be "2b" right?

How does this function work?

[Scott MacKenzie]

In your example, k = -1, so the shift is to the right, not the left.

[Kaavya N]

thanks

[Stephen23]

"the function converts 56 to binary value ie 0101 0110"

You appear to have mixed up decimal and hexadecimal:

B = '01010110'; % your binary string
D = pow2(numel(B)-1:-1:0)*sscanf(B,'%1d') % decimal

D = 86

D = bin2dec(B) % decimal

D = 86

H = dec2hex(D) % hexadecimal

H = '56'

H = sprintf('%x',D) % hexadecimal

H = '56'

[Kaavya N]

Thank you

Answer 1

[Walter Roberson]

dec2bin(56,8)

ans = '00111000'

In other words, your difficulty is that 0101 0110 is not the correct representation for 56.

[Kaavya N]

So, 56 in binary is 00111000

May I know the conversion logic behind this

[Walter Roberson]

Consider for a moment that 56 decimal can be divided by 2 to get 28, and then divided by 2 again to get 14, and then divided by 2 again to get 7, but that cannot be divided by 2. That is three divisions, so the binary representation must end in three 0's.

[Scott MacKenzie]

It's also worth noting that with each division-by-two the remainder (0 or 1) becomes part of the binary result. The first remainder is the bit on the right (the least-significant bit). Each successive remainder is appended on the left. The following figure might help. It shows the conversion from decimal 26 to the binary equivalent, 11010.