When VTAM® passes control to a performance monitor exit, register contents are as follows:

Register 0:

Entry code:

X'04'

Invoke processing

X'10'

Exit activation

X'18'

Exit replacement

X'20'

Exit deactivation

Register 1:

Address of the performance monitor exit parameter list described at Performance monitor exit routine parameter list

Register 13:

Address of a standard 72-byte save area

Register 14:

Return address

Register 15:

Address of the performance monitor exit's entry point