Example of an assembler main calling an assembler subroutine

Following is a simple assembler main routine that calls the DISPARM subroutine shown in DSPARM subroutine example.

*COMPILATION UNIT: LEASMSB
* =====================================================================

*
*        A simple main assembler routine brings up Language
*        Environment, calls a subroutine, and returns with
*        a return code of 0.
*
* =====================================================================
SUBXMP   CEEENTRY PPA=XMPPPA,AUTO=WORKSIZE
         USING WORKAREA,R13
*
* --------------------------------------------------------------------
*
* Invoke CEEMOUT to issue the greeting message
*
         CALL  CEEMOUT,(HELLOMSG,DEST,FBCODE),VL,MF=(E,CALLMOUT)
*
* No plist to DISPARM, so zero R1. Then call it.
*
         SR    R01,R01
         CALL  DISPARM
*
* Invoke CEEMOUT to issue the farewell message
*
         CALL  CEEMOUT,(BYEMSG,DEST,FBCODE),VL,MF=(E,CALLMOUT)
*
* Terminate Language Environment and return to the caller
*
         CEETERM  RC=0
* ====================================================================
*              CONSTANTS
* ====================================================================
*
HELLOMSG DC    Y(HELLOEND-HELLOSTR)
HELLOSTR DC    C'Hello from the sub example.'
HELLOEND EQU   *
*
BYEMSG   DC    Y(BYEEND-BYESTART)
BYESTART DC    C'Terminating the sub example.'
BYEEND   EQU   *
*
DEST     DC    F'2'               Destination is the LE message file
*
XMPPPA   CEEPPA  ,                Constants describing the code block
* ====================================================================
*        The Workarea and DSA
* ====================================================================
WORKAREA DSECT
         ORG   *+CEEDSASZ         Leave space for the DSA fixed part
CALLMOUT CALL  ,(,,),VL,MF=L      3-argument parameter list
*
FBCODE   DS    3F                 Space for a 12-byte feedback code
*
*
         DS    0D
WORKSIZE EQU   *-WORKAREA
         CEEDSA  ,                Mapping of the dynamic save area
         CEECAA  ,                Mapping of the common anchor area
*
R01      EQU   1
R13      EQU   13
         END   SUBXMP             Nominate SUBXMP as the entry point