Int 21 Fn 4B80  - Dr Dos V3.41 - Run Already-loaded Kernel File            [O]

   AX = 4B80h
   DS:DX -> ASCIZ name of program to EXEC
   ES = segment of PSP for kernel file

Return: only if call failed

Note:  DR DOS uses this call after an AX=4B01h to load the kernel file into
     memory and patching the program's parent-PSP field to point at itself

See Also: AH=4Bh"EXEC"