It's in our code, mostly introduced, I believe,  by a life-long
assembler coder who meant it to signal that this value is zero at
assembly but will be filled at execution time by, for example, the
address of a module after a LOAD macro. He also used it for the length
value in an EXecute instruction.  I think in both cases he was trying to
signal future programmers reading the code that they shouldn't assume
that if the value is zero at assembly, it will be zero at execution
time.  He hoped that using *-* would make the experienced programmers
think and the inexperienced ones ask about it.  We did.

On 2020-04-29 5:00 p.m., Mark Boonie wrote:
I've probably been writing assembler for too long to be asking this question 
now, but what is the purpose of coding '*-*' in some assembler expressions?  
I've seen it in parameter lists (usually as an adcon), operands of executed 
instruction (e.g., MVC 0(*-*,5),0(6)), etc.  As far as I can tell it 
effectively operates the same as '0', so it must mean something to the coder 
and/or the reader (but not to this reader).  Any insights?

- mb


Gary Weinhold
Senior Application Architect
DATAKINETICS | Data Performance & Optimization
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Email: [email protected]
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