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Table Structure for Assembly Language Programs

IP.com Disclosure Number: IPCOM000081724D
Original Publication Date: 1974-Jul-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Rosenthal, SE: AUTHOR [+2]

Abstract

There is described herein a technique for defining data fields in units smaller than that addressed directly by the central processor unit. Such fields can be referenced easily in a uniform and efficient manner. As data descriptions are modified, only the reassembly of the program is required.

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Table Structure for Assembly Language Programs

There is described herein a technique for defining data fields in units smaller than that addressed directly by the central processor unit. Such fields can be referenced easily in a uniform and efficient manner. As data descriptions are modified, only the reassembly of the program is required.

It is well known that data fields can be specified in an assembly language program in units that are not directly addressable by the CPU, e.g., bits, bytes, etc. However, it is the programmer who has to generate the proper code sequence that isolates the desired field. Thus, in many computer systems, if a particular bit of a word is to be tested, the full word containing the bit has to be loaded into the accumulator and undesired bits have to be removed therefrom, by shifting or masking before the bit of interest can be tested. Frequently, the same or similar sequences of code may be required in various parts of the program.

Macros can be used to ease the burden on the programmer and to produce uniform and efficient code. However, changes to the data definition usually require changes to the macros or at least the macro call.

The solution to the above-stated problem, as described herein, is to define the data in a manner that may be used by the macros and which need not be changed as the data definition changes.

In the implementation of the foregoing solution, related data are defined in table structures. The data to be manipulated in units smaller than that addressable by the CPU is included in such table structure. The table definitions then are processed by the generation program particularly designed therefor, rather then in the normal assembly process. The table description to be processed by the generation program includes a table description record to identify the table name and, optionally, the table based address and descriptive title. These elements are followed by one or...