[HaBo]

bad_alloc · 17.07.10, 11:25

Zitat:

The myth that any given programming language is machine independent is easily exploded by computing the sum of powers of 2.

If the result loops with period = 1 with sign +, you are on a sign-magnitude machine.
If the result loops with period = 1 at -1, you are on a twos-complement machine.
If the result loops with period > 1, including the beginning, you are on a ones-complement machine.
If the result loops with period > 1, not including the beginning, your machine isn't binary -- the pattern should tell you the base.
If you run out of memory, you are on a string or Bignum system.
If arithmetic overflow is a fatal error, some fascist pig with a read-only mind is trying to enforce machine independence. But the very ability to trap overflow is machine dependent.

By this strategy, consider the universe, or, more precisely, algebra: let X = the sum of many powers of two = ...111111
now add X to itself; X + X = ...111110
thus, 2X = X - 1 so X = -1
therefore algebra is run on a machine (the universe) which is twos-complement.

Bonuspunkte für den der weiß woher das kommt, ohne Google zu benutzen!

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