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  1.  Home
  2. RPG400-L
  3. December 2009

Re: Date formats (was Frank Doherty will be back on Tuesday (all being well))

It was way before the z80 or 4004. At that time you had to chack explicitly, because the hardware had the "carry" but it did not cause an interupt.

That is the reason why in languages like C or Fortran you could add two positive numbers and get a negative result, no warning.

Dennis Lovelady wrote:

Old computers didn't even detect the overflow, so in the old time there
was no overhead.


Really? What computer was that? Even in the z80 (think TRS-80) (and I
think on the 4004, two generations before the 8080) there was a Carry Flag.
And of course, the 360 that preceded it (and probably most other computers
before that) also detected carry or overflow or whatever you want to call
it.

But the point is moot. This is bad practice. As far as I know, the
practice was (thankfully) contained to the IBM Midrange computers (excluding
AIX), and has always been a performance issue.

Dennis Lovelady
http://www.linkedin.com/in/dennislovelady
--
You can't have everything. Where would you put it?



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