This general macro transfers control to the specified operational
program. The entering program stops.
Format
- label
- A symbolic name can be assigned to the macro statement.
- prog
- The name of the program that is to be entered. This method
generates a VCON resolved at link edit time into a Program Attribute Table
(PAT) displacement. This is the preferred method for specifying the
program name.
- PROGRAM
- The name of the program can alternately be provided via the PROGRAM
parameter. This method generates constant data which will be used at
execution time to determine the PAT displacement. This method has a
longer path length than the one described above.
- prog
- The name of the program that is to be entered.
- (Rx)
- A register (R0-R7) that contains the address of the program
name.
Entry Requirements
R9 must contain the address of the ECB being processed.
Return Conditions
Control is never returned to a program which issues the ENTNC 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 using this macro.
- This macro may be used by control program OPZERO type code when activating
ECB programs. The CP segment entering the ENTNC must be running in the
SVM and have the SVA of the ECB in R9.
- Using the PROGRAM parameter sacrifices some performance. Its use
should be monitored.
- This macro is used when a return is not expected to the current
program. The ENTRC macro should be used when a return is
anticipated.
- A program which issues the ENTNC macro is released from the ECB.
The program level that is made available is used for the specified
program.
- The specified program must have been allocated by the system allocator
(see to TPF System Installation Support
Reference).
- The specified program receives control in its allocated addressing
mode. The operational program registers R0-R7 have the same
value they had when the ENTNC macro was issued. The condition code and
the contents of the scratch registers R14 and R15 are unpredictable.
- Users of the ALASC macro should note the programming considerations in the
ALASC specifications relative to the ENTNC macro.
- In addition to the normal macro trace information the macro trace for this
macro contains the name of the macro being returned to.
- ENTNC cannot be called from an ISO-C segment (coded with BEGIN
TPFISOC=YES).
Examples
None.