Re: Euler Project Problems.

Gwenhwyfaer <[email protected]> Sat, 10 May 2008 21:35:03 +0100
Newsgroups gmane.comp.lang.forth.colorforth
Message-ID <[email protected]>
On 10/05/2008, Albert van der Horst <[email protected]> wrote:
> On Fri, May 09, 2008 at 04:38:47PM -0600, Ray St. Marie wrote:
>  > I've spent a day trying to figure out how I will implement larger then
>  > 32 bit ( 27 really) numbers in colorforth for Project Euler Problem 3.
>  >
>  > Find the Greatest Prime Factor of 600851475143.

> There is a division operator that spans 2 registers, effectively
>  doing the SM/REM action of ISO Forth in one instruction.
>  That is 64 by 32 bit division.
>  It is called IDIV

Unfortunately, it only returns 32-bit (31-bit, if signed) results -
which means that determining whether 3 is a factor of the above number
will necessitate a true double-precision division (64/32 returning
64).

Regards
Gwenhwyfaer