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I know how to compare unsigned binary numbers.

But can you help me compare any signed binary numbers?

Above is my simulation but I don't know how to integrate those signed bits in my circuit correctly. In that setup, my output also reads my signed bit as one of the input not as a polarity.

  • \$\begingroup\$ Signed values use msb as the polarity. Do you know resolution of lsb in each case? I use lower case for bits as in lsb= least significant \$\endgroup\$ – Sunnyskyguy EE75 Nov 4 '17 at 13:41
  • \$\begingroup\$ I am on that part. What I don't know is the connections to the logic gates before connecting it to the magnitude comparator. Can you help me with that? \$\endgroup\$ – Gendrygaming Nov 4 '17 at 13:55
  • \$\begingroup\$ Your title says signed magnitude. So these are not twos complement? (Just want to be absolutely sure.) \$\endgroup\$ – jonk Nov 4 '17 at 19:29
  • \$\begingroup\$ Note that jonk's question is quite germane. Are you really willing to deal with the implications of having plus and minus zero? \$\endgroup\$ – WhatRoughBeast Nov 4 '17 at 22:25
  • \$\begingroup\$ Yes! I am comparing positive and negative values depending on the value of my signed bit. \$\endgroup\$ – Gendrygaming Nov 23 '17 at 12:55

There are many ways to represent signed binary. Each has advantages for different useage.

  • 1's complement, ( simple but has a +/-0)
  • 2's complement, (invert and add 1, better for carry operations)
  • offset binary, (biased so it is monotonic in binary and decimal then zero=10000...)

Once you decide which source representation then you can convert to the standard notiation required for the SN7485N in straight binary or BCD as you wish.

Which source representation did you mean?

  • \$\begingroup\$ I am comparing positive and negative values depending on the value of my signed bit. So I think 2's compliment is more applicable \$\endgroup\$ – Gendrygaming Nov 23 '17 at 12:56

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