flure

Wow, I'm glad I posted here Xuel, when you talk about a display kernel, you think about some code that executes outside DLI and VBI ? With that, I don't see how I could synchronize my code so that the colour changes happen at the end of each line, so that the raster bar displays correctly ?

Hello, This is my very first post on this forum. I started programming the Atari 800 XL about 10 days ago, using WUDSN by Jac! (and it's great!). For a beginning, I would like to make raster bars in mode $C. So I built a display list with only $C mode lines, with a DLI on each one. My DLI currently just changes the colour so that it should draw 16 pixels wide bars. I use VCOUNT for that. I also set up a VBI to move the bar vertically. But I have a few problems : I read here that VCOUNT holds the line number divided by two, and that it can go only from 0 to 155 on PAL, including the 24 blank lines at the start of the display list. This is exactly the point I don't understand correctly. Does that mean that I can use it only from 24 to 155, and thus that I am limited to 131 mode lines in my display list ? De Re Atari states that I could use 192 lines total, I guess it is for NTSC ? Well, I'm a bit lost, and currently my program doesn't do what I expect it to... Included below is my source code, so you can see exactly what my problem is. Any help or pointers would be greatly appreciated, thanks ! PS : sorry for not introducing myself better, I promise I will do it later in a dedicated post. Thanks again for any help. rasters.asm