🚀 go-pugleaf

In article <9401172357.tn73003@aol.com>, <shdwsoftwr@aol.com> wrote:
> 
> Actually I think that the graphing screen is more like 127 by 63 pixels. That
> is from 1 to 127 and 1 to 63. Correct me if I am wrong on this but just try
> setting your xMin to 1 and your xMax to 126 and setting your yMin to 1 and
> your yMax to 62 and see what the coordinates of your cursor are on any given
> point. Then change your xMax to 127 and yMax to 63 and look at the cursor
> coordinates.
> 

All you need to do to find the number of pixels on the TI-85 screen is
count them (easier if the screen is set dark)!  The screen is 21 characters
wide; characters are 6 pixels wide, and there are 2 extra pixels at the
right so

  screen width = 21*6 + 2 = 128

The screen is 8 characters high, and characters are 8 pixels high so

  screen height = 8*8 = 64

These, being powers of 2, are very normal computer screen dimensions. 
Total pixels on the screen: 8192 (2^13).

>
> This would make for a total of 8001 pixels. This number seems quite odd too
> me but I guess it isn't so odd cosidering the TI-85 seems to be able to
> address odd numbered addresses in memory. Something unheard of in the
> Macintosh world.
> 

Which Macintosh world was that?  All Macs can access odd byte addresses. 
The very first models had troubles accessing word or longword data from odd
byte addresses but all Macs sold today can do that too.  The TI-85 uses the
Z80 chip, which has mostly byte-length registers, so it HAS to be able to
access odd addresses-- otherwise half the bytes in memory would be wasted!

  -Greg Ferrar (gregt@math.ohio-state.edu)