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PL/1 Locator Variable Hexadecimal Conversion Function

IP.com Disclosure Number: IPCOM000078219D
Original Publication Date: 1972-Dec-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Wehrly, DS: AUTHOR

Abstract

The function described herein provides a facility for accessing at execution time, a printable hexadecimal value representation of PL/1 locator variables (pointer and offsets).

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PL/1 Locator Variable Hexadecimal Conversion Function

The function described herein provides a facility for accessing at execution time, a printable hexadecimal value representation of PL/1 locator variables (pointer and offsets).

Machine dependent or implementation defined facilities are, with much justification, excluded from higher level languages, although there are numerous exceptions (e.g., IBM Fortran IV 'X' data format; IBM PL/1 UNSPEC built-in function and pseudo variable).

Because the state of the compiler art is not yet to the point where the programmer can debug free from knowledge of machine code and data and without the assistance of a storage dump, it is at best awkward to deny him access to an entire class of data elements upon whose values his programs are predicated. PL/1 locator variables are excluded from examination thru I/O (although the internal bit string can be transmitted, this requires fitting and conversion).

This facility 'HEXPTR' provides a built-in like function thru a PL/1 function procedure block. By use of storage overlays (DEFINED and BASED variables) locator variables are segmented into their 4-bit, half-hex digit components (locator variables being stored as aligned full words).

These elements are used as subscripts into an array dimensioned (Phi:15) with elements Phi-F (hexadecimal notation). The resulting character string hex- data representation is returned to the calling module. The returned value is directly associable wi...