VB6 Recover values of an RGB color

R Sunday as integer
G Sunday as integer
Sunday B as integer

Sub TrouveRGB (Coul As Long)
R = & & HFF And Coul
G = (& & HFF00 And Coul) \ 256
B = (& HFF0000 And Coul) \ 65536
End Sub

What is this can you explain?