how to combine 8-bit binary to form a 16-bit binary

The code so far is below, the inputs are two ip address, ip1 = '192.168.0.31', ip2 = '192.168.0.30', upd = 10

the task is to do a ipv4 upd pseudo header checksum, with the input values in decimal and output in binary number

the basic idea as an example:

given an ip address = '192.168.30.'

192 = 1100 0000

168 = 1010 1000

0 = 0000 0000

31 = 0001 1111

the two 8-bit binary should be combined to form a 16-bit value:

192 and 168 = 1100 0000 1010 1000

0 and 31 = 0000 0000 0001 1111

https://www.securitynik.com/2015/08/calculating-udp-checksum-with-taste-of.html link to the task i wanted to do in matlab

function [hd] = in(ip1,ip2,udp) % input values in decimals

source = str2double(strplit(ip1, '.'));
dest = str2double(strplit(ip2, '.'));

protocol = 17;       % udp protocol set to 17

hd1 = de2bi((source),8 , 'left-msb');       % converting from decimal to binary
hd2 = de2bi((dest),8, 'left-msb');

end

Answer 1

[Walter Roberson]

de2bi(source(1:2:end)*256 + source(2:2:end), 16, 'left-msb')

[Earl Gozum]

thank you, for the help

Answer 2

[Steven Lord]

Take a look at the typecast and swapbytes functions.

format hex
x = uint8([192 168])

x = 1×2

c0 a8

y = typecast(x, 'uint16')

y = uint16
   a8c0

z = swapbytes(y)

z = uint16
   c0a8

format longg
results = [uint16(x); y 0; z 0]

results = 3×2

192 168 43200 0 49320 0