Subj : Re: C64 BASIC - what's faster INT() or %? Plus benefits of DEF FN A()
To   : All
From : Holger
Date : Thu Apr 19 2018 13:21:31

Am 17.04.2018 um 04:46 schrieb John H. Guillory:
>   SB> For clarification, which is faster?
>   SB> 10 X=INT(64*RND(0)+1)
>   SB> or
>   SB> 10 X%=64*RND(0)+1
>
> Just guessing, I'd say the second one, or 10 X%=64*RND(0)+1
> because in the first, your converting 64*RNND(0)+1 to an integer, then
> converting back to a single precision decimal point value.
>
Effectively, calculations always happen in floating point, and INT()
returns a FP value in the floating point accu. Conversion will take
place on assignment to the destination variable. The INT() operation is
similar to the truncation operation to fit the FP accu value into X%.
In fact, the major difference is that the first line has to copy 5 bytes
into a variable space and the second will copy 2 bytes.

There isn't even an advantage in space requirement for the variable;
both need 7 bytes, i.e. 2 bytes for the name (like A1 or B2% or C3$) and
5 for the value; an integer variable just wastes 3 bytes for the value.
It is different for integer vs. float arrays; in this case a % value is
indeed packed into 2 bytes.

-hl

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