Re: Laser 128 - questions...

[Ed Eastman <noone@nowhere.net>]

Michael J. Mahon wrote:
> So it is interlaced, with the odd half of screen 1 followed by the 
odd  half of screen 2 in the first field, followed by the even half of 
screen 1 and the even half of screen 2?

Interlaced no, squished to fit, yes.  Perhaps my interpretation of 
interlaced is different than yours.  I believe you are suggesting that 
the mode shuffles the lines together like a deck of cards or stacks them 
side by side for a right/left merging.  It does not.  It stacks page one 
and page two of either HGR or DHGR screens like two bricks, one on top 
of the other.  Each graphic is squished so it all fits in the normal 
display area and effectively gives you twice the verticle resolution for 
any A2 standard video mode.  (I'm uncertain which video modes it does 
NOT work in.  I am not sure it works HR and DHR.)

40 column Text mode, page 1 or 2: 40h x 24v as text
$400-7ff or $800-bff

80 column Text mode: 80h x 24v as text
$400-7ff (main ram) & $400-7ff (aux Ram)

(lores) Gr mode, page 1 or 2: 40h x 48v x 16c
$400-7ff or $800-bff

(lores) DGR mode: 80h x 48v x 16c
$400-7ff (main ram) & $400-7ff (aux Ram)

HGR mode, page 0 1 2 or 3: 280h x 192v x 5c
$0-1fff, $2000-3fff, $4000-5fff, $6000-7fff

DHR mode 1 or 2: 560h x 192v x 16c
$2000-3fff (main ram) & $2000-3fff (aux ram)
$4000-5fff (main ram) & $4000-5fff (aux ram)

Laser128 only:
QGR mode, single page consisting of page 1 and page 2 of normal mode: 
280h x 384v or 560h x 384v
Memory is page 1 _and_ page 2 of given mode, page one in the upper half 
of the screen, page two on the lower half.

Thankx,
Ed