Int 10 Fn 0580  - Video - Pcjr, Tandy 1000 - Get Crt/cpu Page Registers    [V]

   AX = 0580h

Return: BH = CRT page register
   BL = CPU page register

Notes: the CPU page determines which 16K block of the first 128K of physical
     memory will be mapped at B800h by the hardware
   the CRT page determines the start address of the memory used by the
     video controller

See Also: AH=05h"SET CRT/CPU"