If FEATURE_XMS_SWAP is undefined, the Parent Process Interrupt 22h handler is not set

[ecm-pushbx]

The PPI should be set to point to FreeCOM's own handler when the FreeCOM PSP's PPR (Process Parent Process) is set to self-owned. Refer to dosemu2/fdpp#97 (comment) which refers to

freecom/shell/init.c

Line 191 in b0e5984

pspTermAddr = terminateFreeCOMHook;

and

freecom/shell/cswap.asm

Line 216 in 8153543

;; central PSP:0xa hook <-> may be called in every circumstance