Get Extended Processor Exception Handler Vector (Real Mode)

Returns the address of the client's protected mode handler for the specified real mode exception.

Call With

AX = 0211H
BL = exception number (00H-1FH)

Returns

if function successful
Carry flag = clear
CX:(E)DX = selector:offset of exception handler

if function unsuccessful
Carry flag = set
AX = error code

8021H invalid value (BL not in range 00H-1FH)

Notes

CX:(E)DX does not specify a real-mode segment:offset. The reason is that this function allows a client to get the address of the exception handler which will receive control in protected mode when the specified exception occurs in real mode (i.e. the host will provide an implied mode switch for the purposes of servicing the exception, then return to real mode after the handler exits).
Real mode exceptions are sent to the primary client of the virtual machine.