Difference between signed and unsigned 16bit BCDs?

Question

How do you tell the difference? For example, say you have 0110 0101 1001 0011. The unsigned BCD is 6593, but what is the signed value?

score 1 · Accepted Answer · edited Sep 03 '11 at 13:45

1

Usually, you tell the difference by explicitly storing the sign.

Radix complement (en.wikipedia.org/wiki/Method_of_complements)

edited Sep 03 '11 at 13:45

trusktr

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answered Nov 11 '10 at 00:37

dan04

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well it's wierd because in my Assembly class `0110 000 000 000` is supposedly 6000 unsigned (obviously) but -4000 signed. How is that -4000 signed? – trusktr Nov 11 '10 at 00:39
aha, that is indeed what is going on here. You shoulda posted an answer! – trusktr Nov 11 '10 at 01:01

score 0 · Answer 2 · answered Nov 11 '10 at 00:59

in normal binary system, signed numbers uses the MSB (most significant bit) to determine the sign of the number, the rest of the number is the actual value.

Unlike that in Packed BCD, the 4 LSb (least significant bits) represent the sign, and the rest (to the left) of the number represents the actual value.

Difference between signed and unsigned 16bit BCDs?

2 Answers2