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Thread: Minus zero degrees

  1. #11
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    In sign-magnitude number representation, or for that matter in ones' complement notation, minus zero does, in fact, exist.

    Plenty of computers used those systems as well. Heck, you even had minus zero on decimal machines, like the 1620.

  2. #12

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    There is a Chinese brand of consumer products called Vbestlife. I think they tried to be better than me.

  3. #13
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    In two's complement, every binary representation is utilized. What happens to the -0 in your systems? I guess they're so popular for a reason.

  4. #14
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    Well yes, they were popular in their day. DEC PDP-1, CDC 6600, 1604; IBM 7090, Univac 1100 series, IBM 1620 and 1401 to name a (very) few. I believe that the Burroughs 5000 and subsequent stack machines were sign-magnitude.

    The trick in the CDC hardware (designed by that nobody, Seymour Cray) is that the adder used is really a subtractor, so you complement the minuend before operating to add. This leads to the issue of getting a minus zero as the result of addition very rare. The benefits are a symmetrical number representation (there are just as many negative numbers as positive); logical complementation is exactly the same as arithmetic negation, leading to some interesting properties (such as doing multidigit BCD addition and subtraction with one operation).

    Sign-magnitude representations, are of course, naturally this way, as is human written representation (i.e. we don't write negative numbers as their tens' complement).

    Oh--and IEEE 754 floating point is sign-magnitude.

    Really, you need to broaden your horizons...
    Last edited by Chuck(G); December 28th, 2018 at 11:40 AM.

  5. #15

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    Quote Originally Posted by Agent Orange View Post
    I sure drank a lot of Kirin and Asahi in my younger days while stationed in Japan. Always thought it to be pretty good. Disgusting is pretty harsh.
    Our ship was homeported in Yokosuka and I spent a couple years around Japan. Sapporo was my Japanese beer of choice.

    A comment: don't go out drinking with a Japanese sailor and try to find a common language by lots of cold sake in water glasses while laughing and mumbling incoherently. Your head may suffer a bit the next day

  6. #16
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    Quote Originally Posted by Chuck(G) View Post
    Sign-magnitude representations, are of course, naturally this way, as is human written representation (i.e. we don't write negative numbers as their tens' complement).

    Oh--and IEEE 754 floating point is sign-magnitude.
    Sign-magnitude was still covered in Comp Org when I went through the CS program at $university. I don't remember if we had to implement anything using it.

  7. #17
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    Never did any packed BCD arithmetic? That's S-M--and that extends to the present day.

  8. #18

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    When I first saw that "minus zero degrees" site, my first thought was this song - https://www.youtube.com/watch?v=ruvnKqeBv54
    The song is from 1983, the same era as IBM 51xx!

  9. #19
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    Many years ago, when deciding on a domain name, I wanted something like google, googleplex, infinity, inifintysquared, minuszero, roundsquare, etc., but they were all taken.

    Minus zero degrees was the next best thing.

    (I see that sphericalcube.net is available.)

  10. #20

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    Quote Originally Posted by modem7 View Post
    Many years ago, when deciding on a domain name, I wanted something like google, googleplex, infinity, inifintysquared, minuszero, roundsquare, etc., but they were all taken.
    Maybe if you knew how to spell googol and googolplex properly, those domains wouldn't have been taken.

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