If you want get the values for each input, you should sweep the values in your testbench, perhaps from 0 to 255. Here is a link that does this on Eda Playground:
http://www.edaplayground.com/x/2bx
Output:
in=00000000, out = sin(in) = 10000000
in=00000001, out = sin(in) = 10000011
in=00000010, out = sin(in) = 10000110
in=00000011, out = sin(in) = 10001001
in=00000100, out = sin(in) = 10001100
in=00000101, out = sin(in) = 10001111
...