Online HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens
INT 1C - System Timer Tick (User Routine)
- called by INT 8, approximately 18.206 times per second
(unless the program modifies the 8253 PIT
- this is a user routine which the BIOS defaults to a simple IRET
- this interrupt vector can be used for TSR popup utilities,
animated graphics updates and event polling
- since many TSR's don't maintain the integrity of the interrupt
call chain, relying on this for TSR popup isn't recommended
[helppc.bosbyte.nl] user timer routine