OS_Use, fetch information about process card usage

RST 20H, DEFW $EE06

IN:

     BHL = pointer to stacked process environment
     IX = static process id (handle)
     C = dynamic process id

     A0 = 1, if card slot 0 used
     A1 = 1, if card      1
     A2 = 1,              2
     A3 = 1,              3

Internal operating system usage.
 

     -

OS_Poll, poll for an application
DC_Pol, poll for card usage
OS_Ent, enter an application
DC_Ent, enter new application
DC_Nam, name current application
OS_Exit, exit an application
DC_Bye, exiting current application
OS_Bye, exit application
OS_Stk, stack current process (application)