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Structured Macro Extensions

z390 has extended the HLASM macro syntax to add support for structured macro code. This is sometimes referred to as Structured Programming Extensions or SPE.

Warning

z390 structured macro extensions are not supported by IBM HLASM. You need to translate the macros from structured to standard first.

Instructions

Alternate selection of code blocks

  • AIF (expression) - execute the following block of code if expression is true
  • AELSEIF (expression) - end prior block and execute following block if expression is true
  • AELSE - end prior block and execute following block if prior AIF and AELSEIF false
  • AEND - end last block for AIF at current level of nesting

Repeat execution of code block

  • AWHILE (expression) - repeat following code block while expression is true (test at beginning)
  • AEXIT AWHILE - exit to end of inner most AWHILE (for exceptions within nested AIF)
  • AEND - end block of code for AWHILE at current level of nesting
  • AUNTIL (expression) - repeat following code block until expression is true (test at end)
  • AEXIT AUNTIL - exit to end of inner most AUNTIL (for exceptions within nested AIF)
  • AEND - end block of code for AUNTIL at current level of nesting

Perform code block

  • ACALL name - call the named code block and return to next instruction
  • AENTRY name - define start of performed block of code (skip over if entered sequentially)
  • AEXIT AENTRY - exit from AENTRY block of code (for exceptions within nested AIF)
  • AEND - end the current performed code block and exit to next statement after APM

Perform selection of code blocks based on index from 0 to 255

  • ACASE (expression) - execute selected block based on value of index expression
  • AWHEN values - define end of previous block and start of code block for index values
    • values can be decimal (0-255), character C'?', or hex X'??'
    • one or more values may be specified separated by commas
    • a range of values may be specified as (value1,value2)
    • for example AWHEN (C'0',C'9') defines EBCDIC digits 240-249
  • AEXIT ACASE - exit to end of current ACASE (for exceptions within nested AIF)
  • AELSE - define optional code block if no AWHEN block defined for current index

  • AEND - end code block for ACASE

  • Additional extension to indent label field by preceding with colon (:)

Translating to standard

The following items are included for general use:

  • zstrmac - script to convert macro to standard HLASM format
  • bldzstrmacs - script to translate all the SPM's in z390\mac directory to HLASM compatible format
  • rt\test\ZSTRMAC2.ZSM - structured translator which can be translated to standard HLASM compatible code using itself.
  • rt\test\ZSTRMAC1.MLC - bootstrap structured translator which is HLASM compatible.
  • linklib\zstrmac.txt - the generated HLASM compatible translator.

Regression tests

You can execute the regression tests by using the script runzstrmactests.

The following regression test programs are included:

  • rt\test\ZSTRMAC1.MLC - bootstrap version of translator written in standard HLASM.
  • rt\test\ZSTRMAC2.ZSM - structured version of the translator which uses all the structures.
  • rt\test\TESTSPE1.ZSM - test program for ZSTRMAC1 with all the basic structures.
  • rt\test\TESTSPE2.ZSM - test program for ZSTRMAC2 with all the basic structures in lower case
  • rt\test\TESTSPE3.ZSM - test of all 256 ACASE values using all forms of AWHEN operands
  • rt\test\TESTSPE4.ZSM - test error messages
  • rt\test\TESTSPM1.MLC - test program for structured programming macros

Demo

The following demo programs using the macro extensions are include:

  • demo\DEMOM8Q1.MLC - solve 8 queens chess problem suing recursive structured macro

Utilities

The following z390 utility programs using the macro extensions are included:

  • linklib\RTGENDIR.MLC - read file system directory and create list of file names
  • linklib\RTGENCMP.MLC - read merged list of files from 2 directories and generate compare commands
  • linklib\RTGENDIF.MLC - read difference files and generate erase commands for identical files

The following system macros use the macro extensions:

  • EQUREGS.MAC - generate EQU symbols if not already generated for GPR and FPR registers
  • ZCLOSE.MAC - close files (called from CLOSE and other user macros in concatenated directories)
  • ZOPEN.MAC - open files (called from OPEN and other user macros in concatenated directories)
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