Addressing and residence mode of EFS program user exit routines

DFSORT supplies the following features to allow residence above or below 16MB virtual and use of either 24-bit or 31-bit addressing:

f (bit 0 of EFS program exit routine address)

0: Enter the EFS program exit routine with 24-bit addressing in effect.
1: Enter the EFS program exit routine with 31-bit addressing in effect.

The EFS program user exit routine can return to DFSORT with either 24-bit or 31-bit addressing in effect. The return address that DFSORT placed in register 14 must be used.

Except for the EFS program context area address (which DFSORT sends to the EFS program user exit routine unchanged), DFSORT handles the EFS program exit routine parameter list addresses (that is, the pointer to the EFS program exit routine parameter list and the addresses in the parameter list) as follows:

If the EFS program exit routine is entered with 24-bit addressing in effect, DFSORT can pass clean (zeros in the first 8 bits) 24-bit addresses or 31-bit addresses to the EFS program exit routine. The EFS program exit routine must return clean 24-bit addresses if the EFS program exit routine returns to DFSORT with 31-bit addressing in effect.
If the EFS program exit routine is entered with 31-bit addressing in effect, DFSORT can pass clean 24-bit addresses or 31-bit addresses to the EFS program exit routine. The EFS program exit routine must return 31-bit addresses or clean 24-bit addresses.