INT 21 P - Phar Lap 386/DOS-Extender - RESET DOS EXTENDER DATA STRUCTURES
AX = 2501h
SS = application's original SS or DS (FlashTek X-32VM)
Return: CF clear if successful
CF set on error
caller is operating on X-32 stack (FlashTek X-32VM)
Notes:  Phar Lap uses INT 21/AH=25h as the entry point for all 386/DOS-Extender
system calls.  Only available when directly using 386/DOS-Extender or
a compatible DOS extender, or when using a product that was created
using 386-DOS/Extender or a compatible
this function is also supported by FlashTek X-32VM

See also: 2130

212501 - Phar Lap 386/DOS-Extender - RESET DOS EXTENDER DATA STRUCTURES