Re: A83: inversing the screen

To: assembly-83@lists.ticalc.org
Subject: Re: A83: inversing the screen
From: Harper Maddox <gte172i@prism.gatech.edu>
Date: Sun, 18 Feb 2001 15:45:38 -0500
In-Reply-To: <f2.79a72c9.27c17690@aol.com>
Reply-To: assembly-83@lists.ticalc.org


heh. my bad. :)
thats what i get for not cutting and pasting.
i didnt know that ld a,(hl) / cpl was faster than ld a,255 / xor (hl)

-harper

At 02:03 PM 2/18/01 -0500, you wrote:
>A bit faster and smaller, and actually increments hl :P
>
>invertScreen:
>  ld hl,plotsscreen
>  ld bc,3
>invertLoop:
>  ld a,(hl)
>  cpl
>  ld (hl),a
>  inc hl
>  djnz invertLoop
>  dec c
>  jr nz,invertLoop
>  ret
>
>In a message dated 2/18/01 2:01:30 PM Eastern Standard Time,
>gte172i@prism.gatech.edu writes:
>
>
>>invertScreen:
>>  ld hl,plotsscreen
>>  ld bc,767
>>invertLoop:
>>  ld a,255
>>  xor (hl)
>>  ld (hl),a
>>  dec c
>>  jr nz,invertLoop
>>  djnz invertLoop
>>  ret
>
>
>
>
>----
>Jonah Cohen
><ComAsYuAre@aol.com>
>http://jonah.ticalc.org

References:

Re: A83: inversing the screen

From: ComAsYuAre@aol.com