INT 10 - EGA Register Interface Library - WRITE ONE REGISTER
AH = F1h
DX = group index (see AH=F0h)
if single register:
BL = value to write
otherwise
BL = register number
BH = value to write
Return: BL = data
Note:   the RIL is provided by EGA.SYS, the Microsoft Mouse driver, the OS/2
compatibility box, and others
SeeAlso: AH=F0h,AH=F3h

See also: 107F05

10F1 - EGA Register Interface Library - WRITE ONE REGISTER