Re: [colorforth] XcolorForth crashes on read or write to frame buffer.

[Mark Slicker <maslicke@xxxxxxxxxxx>]

'frame' returns a byte address,  !  writes to a word address. You need
to divide by 4 if you wish to use  @  or  !  . Also you may
want to define a word '2!' two write two bytes to a byte address.

macro
: 2! [a!] $28966 3, [drop] ; forth

The frame buffer is 16-bits per pixel in a 5:6:5 format.

On Fri, 31 Oct 2003, Samuel A. Falvo II wrote:

> I'm trying to plot some points to the display, and unfortunately, any
> write to the frame buffer segfaults the executable.  It also appears
> that reading from the framebuffer also causes a crash.
>
> Here is my code (in punctuated form):
>
> : px over ! 4 + ;
> : r $FF0000 px ;
> : g $FF00 px ;
> : b $FF px ;
> : rgb [ frame ] r g b ; rgb
>
> (Note: [ XYZ ] indicates that XYZ is yellow.)
>
> Any ideas as to why this is happening?
>
> Thanks for the help.
>
> --
> Samuel A. Falvo II
>
>
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