Category: DOS-based task switchers/multitaskers
INT 11 - BACK&FORTH (before v1.62) API
AX = FFFEh
CX = FFFEh
BX = function
00h installation check
Return: AX = installation state
0001h BNFHIGH and BNFLOW both loaded
0003h only BNFHIGH loaded
else neither loaded
Return: DX:AX -> ???
05h ??? switches current PSP segment and stack if BNFLOW has not
yet announced itself installed
Return: AX = ???
SeeAlso: INT 12/AX=FFFEh
Index: installation check;BACK&FORTH