A couple of years ago I learned enough assembler to convert a MS-DOS Lemmings Music Player to Mortal Kombat 1.

The timing uses BIOS Wait int 15h ah=86h, which only seems to work properly with DOSBox.

Can you point me to a resource for converting int 15h ah=86h to a ISR? I seem to recall that a ISR has more accurate timing but I haven't studied in a long time so I forgot most of what I learned.

EDIT: Swapped TSR to ISR.