LZ: RE: a simple routine

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LZ: RE: a simple routine

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From: 	chris porter <Erols Technical Support>[SMTP:cbporter@erols.com]
Sent: 	Thursday, July 04, 1996 9:13 PM
To: 	list-zshell@defiant.rbk.sollentuna.se
Subject: 	LZ: a simple routine


can someone show me a simple routine for ploting a pixel on the screen, i
have read zteach.asm's and all, but none of them tell me exactly what
(FIND_PIXEL) does, does it put a one in a if there is a pixel on and a 0 if
it is off? anyway, all i need is a routine that plots one pixel it doesnt
matter where (as long as it is on the screen ;)  ) it would be greatly
appreciated thanx.
chris porter
cbporter@erols.com






these are routines that plot a pixel, delete a pixel and test a pixel...


Make sure u set grafix mode before u use these
--------
PutPixel
parameters:
*B=x coordinate
*C=y coordinate
**destroys DE!


	ROM_CALL(FIND_PIXEL)
	ld	de,$FC00
	add	hl,de
	or	(hl)
	ld	(hl),a
	ret


--------
DelPixel
parameters:
*B=x coordinate
*C=y coordinate
**destroys DE!


	ROM_CALL(FIND_PIXEL)
	ld	de,$FC00
	add	hl,de
	xor	255
	and	(hl)
	ld	(hl),a
	ret


--------
GetPixel
parameters:
*B=x coordinate
*C=y coordinate
returns:
      *if A=0 =>pixel is off
      *if A>0 =>pixel is on
**destroys DE!


	ROM_CALL(FIND_PIXEL)
	ld	de,$FC00
	and	(hl)
	ret




hope this is helpfull...


-Keith Batten
-99kbatten@kamsc.k12.mi.us