I got this...
after hitting return a blank screen, and after hitting return again I'm back at the prompt.

amadeus777999 wrote on 2025-02-28, 20:39:

I got this...
after hitting return a blank screen, and after hitting return again I'm back at the prompt.

thanks a lot! very helpful

ok, the small exe what do is print "hello this is is a test of 9x16 font" then wait for a enter, and should be print "hello this is is a test of 8x16 font"

if not, is not changing to 8x16 640x400

Testing on this hardware:

First, I get this:

After ENTER - empty black screen, without even the blinking cursor.

Ok thank guys then the code is not working in real hardware

thats good to know then i dont need to keep losing time with this line of the code

Im still thinking if is possible to disable 9bit for 80x25

I got both texts, but they look the same to me, it didn't seem to have switched, the monitor reports 70Hz for both.
Tested on an nVidia Vanta LT in MS-DOS 6.22.

Kalle wrote on 2025-03-01, 20:55:

I got both texts, but they look the same to me, it didn't seem to have switched, the monitor reports 70Hz for both.
Tested on an nVidia Vanta LT in MS-DOS 6.22.

thanks definitive test for me, since i have a riva 128 in my DOS computer

thanks a lot!!!

You're welcome. Out of interest I also took a deeper look at it and experimented with it. What you see in the screenshots is what you want, right?

From what I understood, this is what you have to do:
- Reset the sequencer, changing the clocking mode reg to a character width of 8 (3C4h to 1, 3C5h to (3C5h or 1))
- Set the char width of 8 in the pixel panning reg of the attribute controller (read 3DAh to prepare it, then write 13h, 0h and 20h to 3C0h)
- Set the misc output reg to the 25MHz pixel clock (3C2h to (3CCh and 0F3h))

Kalle wrote on 2025-03-02, 11:22:

You're welcome. Out of interest I also took a deeper look at it and experimented with it. What you see in the screenshots is wha […]
Show full quote

You're welcome. Out of interest I also took a deeper look at it and experimented with it. What you see in the screenshots is what you want, right?

From what I understood, this is what you have to do:
- Reset the sequencer, changing the clocking mode reg to a character width of 8 (3C4h to 1, 3C5h to (3C5h or 1))
- Set the char width of 8 in the pixel pannel reg of the attribute controller (read 3DAh to prepare it, then write 13h, 0h and 20h to 3C0h)
- Set the misc output reg to the 25MHz pixel clock (3C2h to (3CCh and 0F3h))

Oh man yes this is what i want, but since i did not jave right now my computer i did not have chance to do some trial and error

You made what i was looking for! did you do in asm?

thanks a lot for test, interest and help

Kalle wrote on 2025-03-02, 11:22:

You're welcome. Out of interest I also took a deeper look at it and experimented with it. What you see in the screenshots is wha […]
Show full quote

You're welcome. Out of interest I also took a deeper look at it and experimented with it. What you see in the screenshots is what you want, right?

From what I understood, this is what you have to do:
- Reset the sequencer, changing the clocking mode reg to a character width of 8 (3C4h to 1, 3C5h to (3C5h or 1))
- Set the char width of 8 in the pixel pannel reg of the attribute controller (read 3DAh to prepare it, then write 13h, 0h and 20h to 3C0h)
- Set the misc output reg to the 25MHz pixel clock (3C2h to (3CCh and 0F3h))

i made a second test following your advice, will be possible can you check? thanks a lot

Yes, it switches fine on my computer now 😀

Kalle wrote on 2025-03-02, 14:24:

Yes, it switches fine on my computer now 😀

Thanks a lot man, your advice was great, i did not need much more to correct asm code

Im happy to find all nice people like one in this forum

Im making a small game for DOS in text mode, and i was thinking to avoid the horrible 9x16 black line effect