"The Ghost In The Machine" wrote in
message ...
| In sci.math, odin
|
| wrote
| on Fri, 9 Sep 2005 16:47:10 -0700
| :
| Dirk Van de moortel wrote:
| By the way, zero is usually taken to be both positive and
| negative.
|
| Hahahahahahahahahahahahahahahahahahahahahahahahaha hahahahahahahaha!
| And you expect to teach OTHERS?!
|
| The IEEE Floating-Point Arithmetic Standard (IEEE 754) defines zero
| representions as positive zero and negative zero. Just about every
CPU on
| the planet uses this standard. If zero is not positive or negative,
then
| what do you figure it is?
|
|
| Personally, I think a modified Law of Trichotomy might apply:
| a real is either positive, zero, or negative. Therefore,
| zero is neither one or the other. Terms such as "nonnegative"
| or "nonpositive" are occasionally used in proof descriptions,
| if one needs to be able to allow or select 0 from a set of reals
| during a proof.
|
| However, there were problems with +0 and -0 in some processors,
| using one's complement arithmetic. Modern processors all use
| two's complement for integers, and there's only one representation
| for 0 therein.

Awww....1000 0000 0000 0000 0000 0000 0000 0000 isn't -0 anymore?

It's not an overflow, I'd double it for that.
1000 0000 0000 0000 0000 0000 0000 0000 * 10 =
1 0000 0000 0000 0000 0000 0000 0000 0000

It's not the highest integer, I can add one to it.
1000 0000 0000 0000 0000 0000 0000 0001

1111 1111 1111 1111 1111 1111 1111 1111 is -1,
I can add one to that and get zero:
1111 1111 1111 1111 1111 1111 1111 1111 +
0000 0000 0000 0000 0000 0000 0000 0001 =
1 0000 0000 0000 0000 0000 0000 0000 0000

So just what is
1000 0000 0000 0000 0000 0000 0000 0000
in modern processors with only one representation for 0?

Androcles