To build GITs, HCD or IPL calls all UIMs at initialization time. For each generic device type that a UIM defines, it must build generic information parameters (GIP) and call the GIT build routine. A GIT is built for each generic device type. The UIM must build GITs before building the UIT.

A UIM invokes the GIT build routine, in 31-bit addressing mode, by using a BALR instruction. Use the standard register save area conventions. The address of the GIT build routine is in the field UCAGITP in the UCA.

GIT Build Routine Input Parameters

A UIM provides the input to the GIT build routine in the generic information parameters (GIP). The GIP resides in the UIM and is mapped by CBDZGIP.

Registers on Entry to the GIT Build Routine

Register 0

Undefined

Register 1

Pointer to a two-word parameter list

• Word 1 - Address of the UCA
• Word 2 - Address of the GIP

Register 2-12

Undefined

Register 13

Address of an 18-word save area

Register 14

Return address

Register 15

The GIT build routine entry point address

Registers on Exit from the GIT Build Routine

Register 0-14

Restored

Register 15

Return code

Return Codes

RC 0

No errors detected, GIT built

RC 8

Error detected, no GIT built, message written