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That's cool, I tested that game I'm making (well is that game engine I posted somewhere in this forum), and the EGA mode is working again at 60 hz on the VGA, like on an original EGA.

That vertical lines are a thing of the monitor, not the card (or at least a combination of the card + monitor). I also have an oak VGA, and you can remove that lines only if the monitor has two settings called "phase" and "clock". This is how the first code posted by juj looks on my monitor +...

The first code was working ok for me, I wanted this to be more compatible, so I think it is ok to have the letterbox mode. The "square pixels" mode works better, I just have to be careful not to use any bright color as color 0 on VGA (or EGA). I'll try this new code later.

It looks like any 320x200@60hz mode on VGA has to be "letter-boxed". This is an image from github, in which they show the correct output for jazz jackrabbit (320x199@60):

It looks great anyway, even if it is not possible without the bands. Also this is great for square pixels in 4:3 monitors.

I just tested the code juj posted, on a real vga + a modern pc monitor, and it is 60hz, but there are still black bands at the top and bottom of the screen, the bottom one is larger. If I set the square pixels, the image is centered, and the top/bottom bars contain overscan (color 0). Both vga...

I had trouble understanding the "back porch" thing, and I did not get the 60 hz mode, I'm going to test this code :biggrin:

That's what I needed :), I want this for a game I'm making, and tweaking the vga registers to get custom modes can be difficult.

Yes, I want this to work on a plain VGA.

Is it possible to get the VGA card to output a full screen 320x200 at 60 hz? (Instead of the default 70hz). I could get 320x240 60hz with black bars at the top and bottom, but it does not look very good. Why do I want 60hz?. Because it is more compatible with emulators, and monitors, and it...

Code is here: source. it was done in c by jsmolina, then I wanted to convert it to assembly, just for fun, and to use little ram. It can be done better, or faster... But speed is not a problem, the program is always stuck waiting for a key press. If I add a wait_vsync function before drawing...

Thanks a lot!. I got errors compiling in TASM, there is probably a different syntaxis for this in every assembler. EDIT: in TASM it works like this: mov CS:[save_DS],ds. Thanks again, it seems to work as intended now, and I managed to reduce the .com size (and ram usage) to 1.5K, that's awesome :).

I converted the program to assembly, it was fun, until I tried to execute programs, (that was not fun). Finally I got it working, but then I realized the exec function (21 4B) does not run .bat files, so I found "function "2E", which is supposed to run everything. It does run any bat, com or...

Just in case someone tries to use inline assembly, the "offset" command won't always work, you have to do this: unsigned char filename = {"myfile.bin"}; unsigned char *name = &filename[0]; //Now use "name" in assembly asm mov dx,name //ASCIIZ filename to open

Thanks a lot! it is working very well, for the moment I'll use inline assembly, then, I'll move everything to asm to reduce size even more I'm going to read tiny 32x16 ascii images (this flanders was the first test), I don't know why the read file is not working in inline assembly asm mov...

Oh sorry this is for 8088/86.

Thanks. This is for a little menu to load programs (with nice ascii graphics in cga), it just needs to be small in ram (that's why I wanted to create a .com file with tiny memory model), It does not matter if it is slow

Thanks. I discovered you can change the used segment in asm by just storing 0xB800 to ds. But i'd love to use the far pointer solution, if it works, because c compiler will do it better than me in asm.

HI, I want to create a small .com program using the tiny memory model, but I don't know how to access video ram (in text mode) to draw some ascii "images". I'm writting stuff to vram using pointers like this: unsigned char *TILE_MAP = (unsigned char *)0xB8000000L; // this points to VRAM Then...

Thanks! I wish I had my old pc, an IBM PS/2 with MCGA 😞.