INT 70 - Real Time Clock Interrupt (XT 286,AT,PS/2)

- called 1024 times per second for periodic and alarm functions

- decrements a DWORD counter by 976µ sec (1/1024)

- when DWORD reaches zero, bit 7 of designated wait flag is set

- if alarm was enabled by ~INT 1A,6~, ~INT 4A~ is called when

counter reaches zero to activate alarm handler

- not available in model 30 PS/2

- see ~INT 15,83~ ~INT 15,86~