INT 15,89 - Switch Processor to Protected Mode

AH = 89h

BH = IRQ8 interrupt vector offset

BL = IRQ0 interrupt vector offset

CX = offset into protected mode CS to jump

ES:SI = pointer to Global Descriptor Table (~GDT~)

on return:

CF = 0 if successful

= 1 if error

- switches 286 and 386 machines into protected mode to take

advantage of advanced feature and extended memory

- Global descriptor table must be setup before interrupt

- normal BIOS functions are not available after the switch