INT 10,5 - Select Active Display Page

AH = 05

AL = new page number, see ~VIDEO PAGES~

for PCjr only:

AL = 80h to read CRT/CPU page registers

81h to set CPU page register

BL = CPU page register

82h to set CRT page register

BH = CRT page register

83h to set CPU and page registers

BH = CRT page register

BL = CPU page register

on return: (PCjr only)

BH = CRT page register

BL = CPU page register