a=b(mod c)

[alex]

I knew from my scool, that

1=1(mod 5)

6=1(mod 5)

-1=4(mod 5)

-3=2(mod 5)

and result MUST BE POSITIV !



Why in newlisp

(% -3 5) => -3

and

(mod -2 5) => -2

??

[alex]

I am sorry - NOT NEGATIVE !

[Lutz]

There are various ways to look at this, see http://en.wikipedia.org/wiki/Remainder">http://en.wikipedia.org/wiki/Remainder



newLISP behaves like 'C' or Pascal in this case. '%' and 'mod' in newLISP work like the underlying 'C' library routines: '%=' and 'fmod()'



Lutz

[William James]

This will always give a non-negative result.

Code Select Expand

(define (%% m n , result)
  (set 'result (% m n))
  (+ result (if (< result 0) n 0)))

[alex]

Or

Code Select Expand

(define (%% a b) (% (+ (% a b) b) b)):-)

[William James]

Very nice, but when running on a 6502 processor clocked at 1.79MHz that extra % will cost you.

[HPW]

running on a 6502 processor clocked at 1.7

Do you have newLISP running on such a system?

[William James]

I haven't used my Atari 800XL in ages, but I use my Commodore 64 monitor to watch television; its chroma and luminance inputs accept S-video via a customized cable.

[HPW]

I have also an old C64 standing around in my workplace.



But your post gave the impression, that you run newLISP on a aged hardware. Was this impression wrong?

[William James]

I was only joking.  (If you have a working C64 monitor, try running S-video from a DVD player to its chroma and luminance inputs; the picture is very clear.)