About DLIs. values

[José Pereira]

Hex. Decimal Instruction

0 0 Leave 1 blank display line

10 16 Leave 2 blank display lines

20 32 Leave 3 blank display lines

30 48 Leave 4 blank display lines

40 64 Leave 5 blank display lines

50 80 Leave 6 blank display lines

60 96 Leave 7 blank display lines

70 112 Leave 8 blank display lines

2 2 Display as GRAPHICS 0 text mode

3 3 Display as special text mode

4 4 Display as 4-color text mode

5 5 Display as large 4-color text mode

6 6 Display as GRAPHICS 1 text mode

7 7 Display as GRAPHICS 2 text mode

8 8 Display as GRAPHICS 3 4-color graphic mode

9 9 Display as GRAPHICS 4 2-color graphic mode

A 10 Display as GRAPHICS 5 4-color graphic mode

B 11 Display as GRAPHICS 6 2-color graphic mode

C 12 Display as special 160x20, 2-color graphic mode

D 13 Display as GRAPHICS 7 4-color graphic mode

E 14 Display as special 160x40, 4-color graphic mode

F 15 Display as GRAPHICS 8, 1 1/2 color graphic mode

1 1 Jump to location specified by next two bytes

41 65 Jump to location specified by next two bytes and

wait for vertical blank

 

 

 

What is that value 3 that says 'SPECIAL TEXT MODE'?

Edited August 17, 2011 by José Pereira

[+Stephen]

I believe that is the 10-line true descender mode. See this ANTIC article.

[+Cafeman]

I recently discovered this mode - Antic 3 - and its descenders ability. Note the lower case g and y for an example of the descenders part of a letter.

[Alphasys]

Yep, Mode 3 is the descender mode.

 

It is 10 scanlines high, but still uses the 8x8 char matrix. The lower case letters are setup so that the "descender" is actually the top byte of the char.

 

If the lower case "g" is setup as:

..XXXX..
........
........
..XXXXX.
.XX..XX.
.XX..XX.
..XXXXX.
.....XX.

It will actually display in mode 3 as:

........
........
........
..XXXXX.
.XX..XX.
.XX..XX.
..XXXXX.
.....XX.
..XXXX..
........

I'm not 100% sure about this, but I think only the lower case letters are affected in this way, but I could be mistaken. I'll have to investigate this in more depth, but maybe one here can already answer this.

[Rybags]

Top 2 bytes are used acutally.

 

It affects any character with bits 5-6 = 11

[Synthpopalooza]

Top 2 bytes are used acutally.

 

It affects any character with bits 5-6 = 11

 

If you do use this mode ... keep in mind that lowercase ascenders (that is, t, l, b, d, h, k) should be defined in a different range than the other lowercase characters ... stay away from atascii 0-32 and atascii>96 ... this will let your lowercase font look more unified. Lowercase letters in ANTIC 3 forbid the use of the top two rows of the char grid. Using this method you have your ascenders reaching to the top of the grid while your descenders lke g j q p etc. will reach to the bottom.

 

ctrl chars will look strange in this mode too because of the reordering of the lowercase descenders.

 

 

 

 

 

[phaeron]

Vertical reflect (CHACTL bit 2) also doesn't work properly with IR mode 3. It inverts A0-A2 of the font fetch address instead of the row counter, so the descenders don't flip.