language agnostic - Join bits using bitwise operations. Is this even possible? -

what asking if possible join bits in 2 different numbers.

a pseudo-code example:

bytes=array(0x04, 0x3f);  //place bitwise black magic here  print 0x043f; 

another example:

bytes=array(0xff, 0xffff);  //place bitwise black magic here  print 0xffffff; 

yet example:

bytes=array(0x34f3, 0x54fd);  //place bitwise black magic here  print 0x34f354fd; 

i want restrict only , bitwise operators (>>, <<, |, ^, ~ , &).

this should work @ least in php , javascript.

is possible in way?

if i'm not being clear, please ask doubts in comment.

if understand question correctly,
should answer in php:

    $temp = $your_first_value << strlen(dechex($the_length_of_the_second_value_in_hex))     $result = $temp | $your_second_value     print dechex($result) 

update: instead of + use | operator