2002 = (a14 a13 ... a1 a0); a15 = 0... 符号ビット

2002   = (a14 x 2^14) + (a13 x 2^13) + ... + (a1 x 2^1) + (a0 x 2^0)
2002 - a0 = 2 x ( (a14 x 2^13) + (a13 x 2^12) + ... + (a1 x 2^0) )

>a0 = 0

1001   = (a14 x 2^13) + (a13 x 2^12) + ... + (a1 x 2^0)
1001 - a1 = 2 x ( (a14 x 2^12) + (a13 x 2^11) + ... + (a2 x 2^0) )

>a1 = 1

...

2002 = (0000 0111 1101 0010)

-2002 = ~2002 + 1

-2002 = (1111 1000 0010 1101) + (0000 0000 0000 0001)
-2002 = (1111 1000 0010 1110)