Program-to-Program Interface › Access PPI Facilities from Other Programs › Specify Sender and Receiver IDs › Make the Call

Make the Call

When making the PPI call, the following conventions must be followed:

• Register 1 must point to a full word in storage that points to the RPB. The end of parmlist bit (bit 0) of the full word can, but need not, be set.
• Register 13 must point to a standard 18-word save area.
• Register 14 must contain the return address in the calling program. This is normally done using the BALR instruction.
• Register 15 must contain the entry point of CNMNETM (or CNMNETV).
• The program must be in primary addressing mode, not secondary, AR, or HOME mode. It must be in TCB mode. SRB mode callers and cross-memory callers are not supported.

In an XA or ESA environment, all addresses in these registers and in the pointer to the RPB must be valid for the AMODE of the calling program. There is no requirement to be in 31 bit mode.

Note: If a LOAD macro was used to obtain the address of CNMNETM (CNMNETV), the top bit of the returned address can be set. It is acceptable to use BALR, BASR, or BASSM to call it.

Most high-level languages follow the conventions automatically.

Upon return, registers are restored. Register 15 is set to 0. It does not contain a return code. The return code is in the RPB.