IDF address expressions

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IDF Address Expressions are made up of terms separated by plus or minus signs. A term can consist of a program symbol, a hex constant (X'5'), a decimal constant (f'4'), a character constant that is one character in length (c'A'), or an implicit numeric constant (247).

Program symbols are of the form "(module.csect) symbol". If supported by the active LSM, they may also be of the form "(module.csect) STMT#nnnnn". The csect in "(module.csect)" is only needed if the symbol occurs in multiple CSECTs. The module. in "(module.csect)" is only needed if the symbol is not in the currently qualified module. To select the module to be the currently qualified module, use the SET QUALIFY command.

Terms may be followed with a register designator. A register designator consists of the string R0 through R15 or AR0 through AR15, enclosed in parentheses. Using AR0 through AR15 directs the DUMP, SET ALET, and EXTRACT LOCATION commands to use the ALET in the specified AR.

Terms and register designators may be followed by indirection operators (%, :>, ?, =>, ->, &, +>). If an indirection operator follows a term, IDF uses the contents of the word pointed to by the expression evaluated thus far. Similarly, if an indirection operator follows a register designator, IDF is being told how to interpret the contents of the register. The word or register is treated as:
  • A 24-bit address if the % or :> operators are used.
  • A 31-bit address if the ? or => operators are used.
  • A 64-bit address if the & or +> operators are used.
  • The appropriate size (24-bit, 31-bit, or 64-bit) depending on the AMODE of the PSW if the -> operator is used.