User Exits › Exit Routine Programming Considerations › TPCSRMXT Exit › Register Usage at Entry:

Register Usage at Entry:

Common Parameter List

R1

This register contains the address of the parameter list, in the following format:

+0

Contains the TPCSRMXT parameter list.

+4

Contains the TPCSRMXT communication word. The content of this word is set by the exit during its initialization call and is passed unchanged for all subsequent calls.

+8

Contains the full-word of flags used to pass status information to the exit.

+C

Contains the global communication word.

R13

Contains the address of the standard save area.

R14

Contains the return address for CA MIM.

R15

Contains the entry point address for the routine.

All other registers are undefined.

TPCSRMXT Exit-specific Parameter List

+0

Contains the address of the list of devices for this allocation in the following format:

+0

Contains the number of entries in the list.

+4

Contains the UCB address of the first device.

+8

Contains the UCB address of the second device.

+C

Contains the UCB address of the third device...and so on.

+4

Contains the address of the Step I/O Table (SIOT) for this allocation.

+8

Contains the address of the area where the routine can build a revised device list in the following format:

+0

Contains the number of entries in the list.

+4

Contains the UCB address of the first device.

+8

Contains the UCB address of the second device.

+C

Contains the UCB address of the third device... and so on.

The revised list must be a subset of the original list.