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Input/Output Processor that Implements Compact HEX to EBCDIC Coversion Algorithm

IP.com Disclosure Number: IPCOM000106497D
Original Publication Date: 1993-Nov-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Lipps, DR: AUTHOR

Abstract

A method used by an I/O Processor (IOP) which converts a one-byte hex number into a 3-byte EBCDIC string to be displayed to the user in a system message is disclosed. The IOP does the conversion to save system processor overhead.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Input/Output Processor that Implements Compact HEX to EBCDIC Coversion Algorithm

      A method used by an I/O Processor (IOP) which converts a
one-byte hex number into a 3-byte EBCDIC string to be displayed to
the user in a system message is disclosed.  The IOP does the
conversion to save system processor overhead.

      An efficient method needs to be determined to convert a 1-byte
hex number (e.g., X'01', X'51', or X'66') to a 3-character EBCDIC
string with leading zero blanking ('  1',' 81','102') for display to
a system user in a message.  The EBCDIC representation of the desired
results are (X'4040F1',X'40F8F1',X'F1F0F2') respectively, which is
the decimal value of the 1-byte hex number in a "ready to display"
format.

      A solution is the algorithm (Described using PL/x language
syntax) shown below, implemented in an IOP to reduce system processor
overhead.

      The byte is represented as an unsigned integer and a
combination of modulo 10 arithmetic, subtraction and addition are
used to convert the digits one at a time to EBCDIC while checking for
termination so leading zero blanking is also accomplished.  Since the
arithmetic is done using unsigned integers and the results are 1 byte
characters, it is important to use redefinition to eliminate extra
type conversions that are not necessary.