Re: floating point

----- Original Message -----
From: "Dr. Roger Dube" <rogerdube_at_dathq.com>
To: <sftalk_at_forth.com>
Sent: Thursday, April 20, 2006 5:20 AM
Subject: [sftalk] floating point

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> As part of a large program, we include fpmath.f since we need floating
> point
> math. We use FVariable to declare space for a floating point variable,
> and
> then f! and f@ to write to and retrieve from that fvariable. For
> checking,
> we can use f. or f>s . to see what is there. Fdepth before and after
> running basic words reveal nothing left behind.
>
>
>
> The first time we write to the variable, all works fine. The SECOND
> time,
> it fails.
>

Don't you forget to initialize the FPSTACK at the beginning
of any message loop ?

    :NONAME ( -- res ) \ GlWindowProc
        [DEFINED] NUMERICS [IF] #NS FSTACK [THEN]
        MSG SwitchMsgLoop ; 4 CB: GlWindowProc

Do you use the software stack (it's more easy) ?

>
>
> Is there something we need to declare to set aside space? How do we
> use it,
> and how much space should be used for typical FP math functions?

    [#NS is the number of floating point items in the stack.]
    [32 CONSTANT #NS]

>
>
>
> What is the difference between "32 FSTACK" and /NDP? Should both be
> used, or
> one, and what is the reason for a specific choice?

    [FSTACK allocates n elements to the numeric stack for the current
task.
    The stack is also initialized to empty.]

    [/NDP initializes the NDP. It sets the Control Register to the
    value saved in the floating point options registry settings.]

>
>
>
> Is there a debug tool that someone could suggest to help us through
> this?
>

Perhaps have a look at FPDEBUG.

Hoping to help you,
Charles

>
>
> Thanks!
>
>
>
> -- Roger
> --------------------------------------------
> Dr. Roger Dube
> President and Chief Science Officer
> Digital Authentication Technologies, Inc.
> 561.392.7404 (office)
> 561.892.2474 (eFax)
> RogerDube_at_datHQ.com
>
> http://www.datHQ.com
>
> 1900 Glades Road Suite 441
> Boca Raton, FL 33431
>
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Received on Thu Apr 20 2006 - 01:45:58 PDT