$F85F NXTCOL {Increments Lo-res Color by 3}

After looking over parts of the $F800-FFFF ROM over the years, I'm always brushing this entry point to the side, thinking that it was useless. I'm reminded yet again that it is still there. Okay, now I gotta ask... Is there any practical reason why
someone would want to increase the Lo-res color value by 3? I do see that by incrementing by 3's does give an alternate method to cycling through all 16 colors. But if people really wanted to do that, it wouldn't be hard for someone to write their own
simple routine, and those few bytes in ROM could be use for something more useful. I searched through the entire monitor ROM ($F800-FFFF) and BASIC ROM ($D000-F7FF) to see if it was called or even referenced by anything, and it is not. It appears to be
dead code, as there is nothing in either ROM's I could find that actually uses it. I guess it's just there in case anyone wanted to use it?

Color cycles: 0,3,6,9,C,F,2,5,8,B,E,1,4,7,A,D... (loops back to 0)

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

$F85F NXTCOL {Increments Lo-res Color by 3}

After looking over parts of the $F800-FFFF ROM over the years, I'm always brushing this entry point to the side, thinking that it was useless. I'm reminded yet again that it is still there. Okay, now I gotta ask... Is there any practical reason why

someone would want to increase the Lo-res color value by 3? I do see that by incrementing by 3's does give an alternate method to cycling through all 16 colors. But if people really wanted to do that, it wouldn't be hard for someone to write their own
simple routine, and those few bytes in ROM could be use for something more useful. I searched through the entire monitor ROM ($F800-FFFF) and BASIC ROM ($D000-F7FF) to see if it was called or even referenced by anything, and it is not. It appears to be
dead code, as there is nothing in either ROM's I could find that actually uses it. I guess it's just there in case anyone wanted to use it?

Color cycles: 0,3,6,9,C,F,2,5,8,B,E,1,4,7,A,D... (loops back to 0)

Best guess is Apple used it for demos. Rapidly changing, seemingly random colors would make a good visual effect to portray computer graphics on computers for sale in a store. Although, unknown to customers, Lo-res is somewhat limited in its resolution.

Rob

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Saturday, March 13, 2021 at 3:09:31 PM UTC-6, I am Rob wrote:

$F85F NXTCOL {Increments Lo-res Color by 3}

After looking over parts of the $F800-FFFF ROM over the years, I'm always brushing this entry point to the side, thinking that it was useless. I'm reminded yet again that it is still there. Okay, now I gotta ask... Is there any practical reason why

someone would want to increase the Lo-res color value by 3? I do see that by incrementing by 3's does give an alternate method to cycling through all 16 colors. But if people really wanted to do that, it wouldn't be hard for someone to write their own
simple routine, and those few bytes in ROM could be use for something more useful. I searched through the entire monitor ROM ($F800-FFFF) and BASIC ROM ($D000-F7FF) to see if it was called or even referenced by anything, and it is not. It appears to be
dead code, as there is nothing in either ROM's I could find that actually uses it. I guess it's just there in case anyone wanted to use it?

Color cycles: 0,3,6,9,C,F,2,5,8,B,E,1,4,7,A,D... (loops back to 0)

Best guess is Apple used it for demos. Rapidly changing, seemingly random colors would make a good visual effect to portray computer graphics on computers for sale in a store. Although, unknown to customers, Lo-res is somewhat limited in its resolution.

Rob

I was kind of thinking the same thing, for the seemingly random color effect, back when flashing random colors were all the rage (lol).

I just now happened to stumble across this: https://en.wikipedia.org/wiki/Apple_II_graphics > 3.2 Low-Resolution (Lo-Res) graphics
Quote: "Low-resolution colors 0 (black), 3 (purple), 6 (medium blue), 9 (orange), 12 (light green) and 15 (white) were also available in high-resolution mode."

There could be some potential use for someone wanting to draw a palate of the Hi-res colors on the Lo-res screen. I can imagine someone making a Hi-res color drawing program that uses Lo-res to show the Hi-res colors, allowing them to choose one. That
is if they don't care what order they're shown, since Hi-res colors are 1 (green), 2 (purple), 5 (orange), 6 (blue). Hmm. Now I'm starting to think maybe it was for seemingly random color effects. Oh well... moving on... unless anyone else has other
ideas for this.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

It makes me think of the Printshop "printing" graphics, with the coloured rectangles that cycled.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)