Page 106 - DCAP507_SYSTEM_SOFTWARE

System Software

Notes 7.2.1 Concatenation of Macro Parameter

 Most Macro Processor permits parameters to be concatenated with other character strings.
 A program comprises a set of series of variables:
XA1, XA2, XA3,…

XB1, XB2, XB3,…
 If similar processing is to be performed on each series of variables, the programmer
might want to fit in this processing into a macro instruction.

 The parameter to such a macro instruction could specify the series of variables to be
functioned on (A, B, C …).

 The macro processor builds the symbols by concatenating X, (A, B, …), and (1,2,3,…) in the
macro expansion.
 Let such parameter is named &ID, the macro body may comprise a statement: LDA X&ID1,
in which &ID is concatenated after the string "X" and before the string "1".

 LDA XA1 (&ID=A)
 LDA XB1 (&ID=B)

 Ambiguity problem: E.g., X&ID1 may mean "X" + &ID + "1""X" + &ID1. This problem
appears since the end of the parameter is not marked.

Macro Definition

Macro Invocation Statements

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