Re: Setting a pixel on the screen

or word and double word. sorry.

On Wed, May 28, 2008 at 7:09 AM, Ray St. Marie <[email protected]> wrote:
> Ya, gosh, how many programs do I use this! Several! It's funny cuz
> i've never not done it. It's Byte addressing, Please notice that you
> are just setting things up with the 2 leftshifts so that the
> definitions for ! and @ which include the definition   a,  ( defined
> as 2* 2* ) which will return you back to word addressing. I suppose
> this is for Chuck and for ease of use.
>
> Your guess is better then mine. :-)
>
> On Wed, May 28, 2008 at 7:01 AM, Jason Kemp <[email protected]> wrote:
>> ...And that's not right because ! stores a double word and I only want a
>> word (16 bit colour).
>>
>> Block 34 (icons) has !w which stores a 16 bit word to a byte address.
>>  That's what I need instead of 2/ 2/ !
>>
>> Also, on http://www.colorforth.com/forth.html it is stated "Data are
>> addressed as 32-bit words, not bytes."  I'm not fully clear on how this
>> works so I need to look harder.
>>
>> Jason Kemp said the following on 28/05/2008 11:27:
>>>
>>> Hi Ray,
>>>
>>> Thanks for all the encouragement.  I cracked it on Friday and was
>>> intending to reply, but I'm trying not to touch the computer over the
>>> weekends now and Monday was a bank holiday too!
>>>
>>> : pixel show black screen ffff 400 400 1024 * + 2* 1e80000 + 2/ 2/ !
>>> keyboard ;
>>>
>>> It needs a 2/ 2/ because ! multiplies the address it is given by 4.  This
>>> must be something to do with addressing doublewords as opposed to bytes--I'm
>>> sure it's something quite obvious to most but it's taking me a long time to
>>> build up a picture of what's going on here.  Are addresses in colorforth
>>> stored as the count of doublewords rather than a true address?
>>>
>>> Jason
>>>
>>>
>>>
>>>
>>> Ray St. Marie said the following on 27/05/2008 20:23:
>>>>
>>>> rethinking my previous post to this question...
>>>> Hi Jason,
>>>> Ray here
>>>>
>>>> On Tue, May 20, 2008 at 4:41 PM, Jason Kemp <[email protected]>
>>>> wrote:
>>>>
>>>>>
>>>>> Good evening all,
>>>>>
>>>>> I have been attempting to set a pixel on the screen to white.  Please
>>>>> show
>>>>> me what I am doing wrong:
>>>>>
>>>>> : ohno show black screen ffff 400 400 1024 * + 2* 1e80000 + ! keyboard
>>>>> ;>
>>>>> Only the ffff and the 1e80000 are in hex.  The screen is 1024x768,
>>>>> 16-bit,
>>>>> VESA 117h.
>>>>>
>>>>> Thanks,
>>>>> Jason
>>>>>
>>>>>
>>>>
>>>> Jason, have you tried the word color after ffff, to set the color, as
>>>> in...
>>>>
>>>> : ohno show black screen ffff COLOR 400 400 1024 * + 2* 1e80000 + !
>>>> keyboard ;
>>>>
>>>> I happened to be looking in an old source and reading the word SWITCH.
>>>> In the top of the word we see an example of writeing to AGP before
>>>> switching to keyboard.
>>>>
>>>> Karig has a nice look at it :
>>>>
>>>> http://www.karig.net/os/cf/g.htm
>>>>
>>>> Halfway down the page. All of the rest of that page are examples of
>>>> 'emit'ing pixels to the page.
>>>>
>>>> Good luck with this, Jason. Please keep me in the loop, your
>>>> experiments, as I'd like to try them out as well. :-)
>>>>
>>>> All the best,
>>>> Ray
>>>>
>>>>
>>>
>>>
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>>>
>>
>>
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>
>
>
> --
> Raymond St. Marie ii,
> colorforthray.info
>



-- 
Raymond St. Marie ii,
colorforthray.info