An interesting problem.
In B1 enter a valid 4-character hex value:
0000
thru
FFFF
In C1 enter:
=HEX2BIN(LEFT(B1,1),4) & HEX2BIN(MID(B1,2,1),4) & HEX2BIN(MID(B1,3,1),4) &
HEX2BIN(MID(B1,4,1),4)
In D1 enter:
=BIN2DEC(LEFT(C1,6))
In E1 enter:
=BIN2DEC(RIGHT(C1,9))+512*MID(C1,7,1)
I have assumed that bit #0 is the MSB. E & D are your decimal parts. Some
typical values in B thru E are:
0008 0000000000001000 0 8
0E46 0000111001000110 3 582
DEAD 1101111010101101 55 685