Does conditional COPY still look for member? 
Author Message
 Does conditional COPY still look for member?

We have an assembler module which does a conditional COPY (via AIF/AGO/ANOP
logic).  When attempting to assemble the module with the SET symbols set
such that the COPY instruction is not executed, we get a message that the
member specified on the COPY instruction is not found, to wit:

   IEV060  *** ERROR ***  COPY CODE NOT FOUND  --  SASCRAB

The message in itself is correct; the member does not exist on the system
on which the assembly is running.

A further interesting fact is the position of the message within the listing;
although the COPY instruction appears near the end of the module, the error
message appears much closer to the top of the listing.

Final relevant fact: we are running Assembler (H) V2

Speculation: doesn't the assembler do lookahead? And if so, could it be
looking for (via BLDL?) or actually reading in, any member specified on a
COPY instruction whether or not the instruction is actually "executed"?
Is this surprising?  Perhaps not, since the sequence symbol being branched
to might lie within the COPYed code.

Well, sitting here typing this in, I think I've answered my own question,
but perhaps it'll spark some interesting dialog.

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Tue, 19 Oct 1993 03:12:52 GMT  
 Does conditional COPY still look for member?
This is an interesting point.  The COPY operation is applied during
pass 1 of an assembly, and simply redirects the input to a SYSLIB member.
Thus, there is no such thing as a "conditional COPY".  A consequence
of this is that a COPY is _not_allowed_ to be generated by MACRO.  If a MACRO
generates a COPY the error "IEV001 ... OPCODE NOT ALLOWED TO BE GENERATED"
results.

(To generate a COPY you have to "trick" the assembler by defining a SETC
symbol to be 'COPY' and using it in the opcode field.  If you just put
a COPY inside a MACRO definition the text of the copied member will be
placed _inside_ the definition.)



Tue, 19 Oct 1993 06:01:52 GMT  
 Does conditional COPY still look for member?

Quote:
>(To generate a COPY you have to "trick" the assembler by defining a SETC
>symbol to be 'COPY' and using it in the opcode field.  If you just put
>a COPY inside a MACRO definition the text of the copied member will be
>placed _inside_ the definition.)

In fact, I have used COPY to actually insert PORTIONS of conditional code
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Tue, 19 Oct 1993 13:03:20 GMT  
 
 [ 3 post ] 

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