here is a part of my code, this should draw a pixel on the mouse position:
mov ax,3h ;set interruption to getting the mouse pos
int 33h ;after the interruption: cx=x, dx=y
mov ah, 0Ch ;draw a pixel
;the x and y should already be in the registers cx and dx after the last interruption
mov al, 5 ;set color (to some kind of purple)
int 10h ;the drawing should happen here, but for some reason nothing is drawn
btw, im using video mode int 10h/ah=0h/al=12h, which has a 640x480 resolution and 16 colors.
You are geting the mouse cursor position correctly, it should work. I wrote a sample program
plsHelp Program Format=COM
MOV AX,0012h
INT 10h ; Set graphic videomode 640*480.
Repeat:
MOV AX,0003h
INT 33h ; Get mouse position and button status.
TEST BX,2 ; Mouse right-button pressed?
JNZ End
MOV AX,0C05h
INT 10h ; Draw a pixel at CX*DX.
JMP Repeat
End:RET ; Terminate program.
EndProgram
When assembled by euroasm.exe plsHelp.asm and run as plsHelp.com in DosBox on my Windows, moving the mouse leaves a magenta track as expected. Perhaps something is wrong with your environment.