(SYSLIB) Programming Reference Manual - Public Support Login ...

Words 27–39
May also be used for source output, that is, with SOR.
Words 29–38
Contain the relocatable element table item.
14.1.4. Reusable Processor Construction
PREPRM, PREPRO, PREPF$, and POSTPR$
Initial program load operations are expensive relative to swapping. A mechanism is
provided that allows a program to make itself reusable, thereby avoiding the need to
reload itself. This applies to programs called by processor call statements but not by
@XQT. If the processor in question makes use of the standard processor interface
routines (PREPRO, PREPRM, POSTPR$, ROR, SOR, SIR$), implementing reusability is
not a major task. The following describes the appropriate steps.
1. Register the processor name with INFOR CLIST (ER CLIST$), either ASCII or
Fieldata. Use a type 0 list, because an unknown control statement terminates CLIST
mode. See the Exec ER Programming Reference Manual.
2. Become self-initializing or self-reinitializing. This means that any data areas that are
expected to contain particular values at the beginning of the program must be
initialized by a particular instruction sequence. Do not rely on static data initialization.
Do this by explicitly setting all initialized variables to their initial value or by reloading
the main segment. The former method is recommended unless the number of
variables is excessive.
3. Check for potential reusability as indicated in PARTBL by SIR$ (S4 of PARTBL+13;
see Figure 14–1); then call REPRO$ or REPRM$ to read the next INFOR, if any;
reinitialize or terminate depending on which return is given by REPRO$/REPRM$.
This is done with the following steps:
a. If S4 of PARTBL+13 > 0, call POSTPR$, then quit.
b. Zero INFOR$ (see Section 12), then call REPRO$ or REPRM$, setting A0 as
desired.
c. If absolute-eof return, call POSTPR$, then quit.
d. If wrong CLIST value, take action as defined for the particular processor in
question.
e. If error return, treat same as error return from PREPRO or PREPRM.
f. If normal return, reinitialize the processor (and SIR$, if used, by storing 0 in
SIRP2$); begin new processing operation (compilation, assembly, and so on).
7833 1733–004 14–7