LZ: Help on lines!

To: "'list-zshell@lists.ticalc.org'" <list-zshell@lists.ticalc.org>
Subject: LZ: Help on lines!
From: Kevin Retzke <kretzke@enteract.com>
Date: Thu, 12 Dec 1996 22:08:16 -0600
Reply-To: list-zshell@lists.ticalc.org

I need help on how to draw a diagonal line.  I got line.asm, which is a version of Bresenham's algorithm, and since I didn't want to figure out how to do his algorithm in assembler, I pasted the routine in my program.  It draws a line, but for some reason when I tell it to draw a line from $3201(de) to $3F64(hl), it draws it up into tho top of the screen, then jumps down to the bottom and goes up to about 24(decimal).  The X is right, however.  Here's an illustration:
(very crude):
----------------------------------------------------------------------
         ___/                             . ($3F64)
  __ /
/
($3201)
                                       ($1864)
                                    ___/
                           ____/
                    ___/
_________  /_____________________________

Does anybody know what's going on, or what I'm doing wrong?  Is there a better way to do it than this?
Thanks in advance.

Kevin Retzke
kretzke@enteract.com