This general macro returns control to the last program held by the entry
control block (ECB) that issued an ENTRC.
Format
- label
- A symbolic name can be assigned to the macro statement.
Entry Requirements
R9 must contain the address of the ECB being processed.
Return Conditions
Control is never returned to the program that issues the BACKC
macro.
Programming Considerations
- This macro can be executed on any I-stream.
- The ECB reference register (R9) must contain the address of the ECB being
processed before issuing this macro.
- The program that issued the last ENTRC macro will regain control in the
addressing mode in which it was operating prior to issuing the ENTRC
macro. The operational program registers R0-R7 have the same
value they had when the BACKC macro was issued. The condition code and
the contents of registers R14 and R15 are unpredictable.
- Following use of this macro, control can be transferred to the current
program for processing of another message. Accordingly, it may be
necessary to save and reset temporary counters and switches to allow for
proper execution of this program.
- An ENTDC macro must not be issued between the execution of an ENTRC macro
and a BACKC macro. If this sequence occurs, control is transferred to
the system error routine.
- Users of the ALASC macro should note the programming considerations in the
ALASC specifications relative to the BACKC macro.
- In addition to the normal macro trace information the macro trace for this
macro contains the name of the macro being returned to.
- BACKC cannot be called from an ISO-C segment (coded with BEGIN
TPFISOC=YES).
Examples
None.