User defined fonts in VGA BIOS won't persist after performing shell command: CLS (Clear screen)
I've attached an example program with assembly code.
Run example program. Type CLS.
In original DOS the fonts persists.
It does not in DOSBOX (which is either a feature or a bug) :) Imho, a bug.
(It looks like you're doing a mode change or something - I dont think CLS in original DOS is doing a mode change - it probably only clears the screenbuffer and moves the cursor position, if i am not mistaken).
Userfont executable COM file
Userfont assembly file
You should try check if accumulator low bits (AL) have the same video mode before as after CLS if you're calling interrupt 10h.
we do indeed do a modeset in our CLS.
(which is in the dosbox case beneficial as we don't have a mode.com to reset the screen.)
Nonetheless I consider it a bug as well.
Thanks for reporting it