Show Row 12 Hack in Assembly

[Primordial Ooze]

The Atari 2600 has a 12 row display, even though the 12th row is actually hidden.

 

hidden (actually row 1)
row 1( row 2)
row 2 (row 3)
row 3 (row 4)
row 4 (row 5)
row 5 (row 6)
row 6 (row 7)
row 7 (row 
row 8 (row 9)
row 9 (row 10)
row 10 (row 11)
row 11 (row 12)

 

However in batari basic, it was possible to show that row with the penalty that you couldn't scroll the screen or else end up crashing the atari 2600 by adding this code during initiation and before your kernel:

 

pfscroll upup: pfscroll upup

 

What I would like to know is what would be the equivalent to that hack in 6207 assembler? Any help in this matter would be greatly appreciated.

 

Sincerely,

 

Ooze Orbs

Edited October 3, 2010 by Primordial Ooze

[Omegamatrix]

You are confusing the limitation of some batari basic kernel with what the 2600 is actually doing.

 

There are no set number of rows. There are only a certain amount of visible scanlines (about 200 in a modern NTSC homebrew). So you could make lots of rows. Maybe one for each scanline if you wish.

[tokumaru]

In assembly you can do whatever you want for each scanline, you don't have to "unlock" anything. You can divide the screen into as many "rows" as you want, as long as that's less than the vertical resolution (i.e. you can't have 250 rows if the whole screen has only 192 scanlines).

 

Another factor to consider when splitting up your screen is the amount of RAM necessary to keep the state of the rows in case you plan on changing them dynamically during the game (if you don't you could just read the data from ROM, of course).