Bit Manipulation
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Assembler Bit Processing Bit Manipulation |
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| The SimoTime Home Page |
Introduction
This is an example of how a COBOL program calls an Assembler routine to do bit-level manipulation. The three basic functions provided are as follows.
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| The Three Basic Functions provided by the Bit Manipulation Routine |
This example uses an approach of converting the bit information in a single byte to or from an eight-byte field of COBOL accessible zeroes and ones. This example contains one JCL member to execute the two programs. The main COBOL program (CBLBITC1.CBL) is used to demonstrate and test the bit manipulation functions. The bit manipulation functions are in a separate, callable Assembler program (ASM4BITS.MLC). The COBOL program was written and tested using the VS COBOL II dialect. Also, the COBOL program will work with COBOL for MVS and COBOL/370. A JCL member is provided to run the job as an MVS batch job on an IBM Mainframe System or a Windows System with Micro Focus Enterprise Developer.
In the world of programming there are many ways to solve a problem. This suite of programs is provided as a "COBOL calling Assembler" programming example of one of the possible solutions to the problem of determining and changing the bits within a byte. This example may serve as a tutorial for new programmers and as a reference for experienced programmers. Additional information (including a COBOL routine that does bit manipulation) is provided in the Downloads and Links to Similar Pages section of this document.
Note: Refer to the Download and Links to Similar Pages section of this document for links to additional documents that discuss this topic.
We have made a significant effort to ensure the documents and software technologies are correct and accurate. We reserve the right to make changes without notice at any time. The function delivered in this version is based upon the enhancement requests from a specific group of users. The intent is to provide changes as the need arises and in a timeframe that is dependent upon the availability of resources.
Copyright © 1987-2025
SimoTime Technologies and Services
All Rights Reserved
EXPAND the bits of a one-byte field into bytes of an eight-byte field
For each bit that is ON (1) in the BTS-PASS-BITS field the corresponding byte in the BTS-PASS-BYTES field is set to a value of one. For each bit that is OFF (0) in the BTS-PASS-BITS field the corresponding byte in the BTS-PASS-BYTES field is set to a value of zero.
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| Expand Function of the Bit manipulation Routine |
COMPRESS the bytes of an eight-byte field into bits of a one-byte field
For each byte that is a one in the BTS-PASS-BYTES field the corresponding bit in the BTS-PASS-BITS field is set to ON (1). For each byte that is zero in the BTS-PASS-BYTES field the corresponding bit in the BTS-PASS-BITS field is set to OFF (0).
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| Compress Function of the Bit manipulation Routine |
Call Interface
The callable interface requires a data structure to be defined. A copy file (PASSBITS.cpy) is provided with the following source code.
*****************************************************************
* PASSBITS is a COBOL Copy File *
* Data Structure or Pass Area used for calling SIMOBITS. *
* Copyright (C) 1987-2019 SimoTime Technologies *
* All Rights Reserved *
*****************************************************************
* Provided by SimoTime Technologies *
* Our e-mail address is: helpdesk@simotime.com *
* Also, visit our Web Site at http://www.simotime.com *
*****************************************************************
*
* When BTS-PASS-REQUEST is 'EXPAND ' do analysis of
* BTS-PASS-BITS (a 1-btye field of 8-bits)
* and based on the bit settings a corresponding value of
* 0 or 1 is set in the BTS-PASS-BYTES (an 8-byte field
* of zeroes and ones).
*
* When BTS-PASS-REQUEST is 'COMPRESS' do analysis of
* BTS-PASS-BYTES (an 8-byte field of zeroes and ones)
* and based on a value of 0 or 1 the corresponding
* bit in BTS-PASS-BITS (a 1-byte field of 8-bits) is
* switched ON or OFF.
*
01 BTS-PASS-AREA.
05 BTS-PASS-REQUEST PIC X(8).
05 BTS-PASS-RESULT PIC S9(9) COMP.
05 BTS-PASS-RECORD.
10 BTS-PASS-BITS PIC X.
10 BTS-PASS-BYTES.
15 BTS-PASS-BYTE-01 PIC X.
15 BTS-PASS-BYTE-02 PIC X.
15 BTS-PASS-BYTE-03 PIC X.
15 BTS-PASS-BYTE-04 PIC X.
15 BTS-PASS-BYTE-05 PIC X.
15 BTS-PASS-BYTE-06 PIC X.
15 BTS-PASS-BYTE-07 PIC X.
15 BTS-PASS-BYTE-08 PIC X.
*
*** PASSBITS - End-of-Copy File - - - - - - - - - - - PASSBITS *
*****************************************************************
*
The following will translate an eight character field of 0's and 1's to a one byte field with the bits set to match to 0's and 1's of the eight character field. Please note: the content of the BTS-PASS-REQUEST field must be upper case and contain 'COMPRESS'
*****************************************************************
* The coding required to do the call to the Byte-Bit Routine *
* (translate an 8-byte field to a 1-byte field). *
*****************************************************************
MOVE '11111111' to BTS-PASS-BYTES
MOVE 'COMPRESS' to BTS-PASS-REQUEST
CALL 'ASM4BITS' using BTS-PASS-AREA
In the preceding example the contents of BTS-PASS-BITS will be X'FF' or high-value upon return from the call to ASM4BITS.
The following will set the individual bytes of an eight character field to 0's or 1's based on the bit settings of a one byte field. Please note: the content of the BTS-PASS-REQUEST field must be upper case and contain 'EXPAND' followed by two spaces
*****************************************************************
* The coding required to do the call to the Byte-Bit Routine *
* (translate a 1-byte field to an 8-byte field). *
*****************************************************************
MOVE X'55' to BTS-PASS-BITS
MOVE 'EXPAND ' to BTS-PASS-REQUEST
CALL 'ASM4BITS' using BTS-PASS-AREA
In the preceding example the contents of BTS-PASS-BYTES will be '01010101' upon return from the call to ASM4BITS.
The JCL Member
The following is the mainframe JCL member (ASMBITJ1.jcl) that is required to run as a job on the mainframe or as a Mainframe Express project on the PC.
//ASMBITJ1 JOB SIMOTIME,ACCOUNT,CLASS=1,MSGCLASS=0,NOTIFY=CSIP1 //* ******************************************************************* //* ASMBITJ1.JCL - a JCL Member for Batch Job Processing * //* This JCL Member is provided by SimoTime Technologies * //* (C) Copyright 1987-2019 All Rights Reserved * //* Web Site URL: http://www.simotime.com * //* e-mail: helpdesk@simotime.com * //* ******************************************************************* //* //* Text - COBOL calls ASSEMBLER for Bit and Byte manipulation //* Author - SimoTime Technologies //* Date - January 01, 1989 //* //* This set of programs illustrate the use a COBOL program that calls //* an Assembler routine to do bit manipulation. //* This suite of programs will convert between a one-byte //* (consisting of eight-bits) field and an eight-byte field //* consisting of ZEROES and ONES. //* //* The DD statement for SYSOUT is required by this example. The //* COBOL program may be compiled using the SYSOUT directive and //* without the DD statement for SYSOUT an RTS173 or RTS227 may occur. //* //* This set of programs will run on a mainframe under MVS or on //* a Personal Computer running Windows and Mainframe Express by //* Micro Focus. //* //* ************ //* * CBLBITJ1 * //* ********jcl* //* * //* * //* ************ ************ //* * ASMBITC1 *-----* DISPLAY * //* ********cbl* ************ //* * * //* * * ************ //* * *-CALL--* ASM4BITS * //* * ********cbl* //* * //* ************ //* * EOJ * //* ************ //* //* ******************************************************************* //* Step 1 of 1, This is a single step job. //* //ASMBITS1 EXEC PGM=ASMBITC1 //STEPLIB DD DSN=SIMOTIME.DEMO.LOADLIB1,DISP=SHR //SYSOUT DD SYSOUT=* //*
COBOL Mainline Program
This program (ASMBITC1.cbl) was written to test the callable Assembler program (ASM4BITS.mlc) that does the conversion between a 1-byte field of 8-bits and a field of 8-bytes.
IDENTIFICATION DIVISION.
PROGRAM-ID. ASMBITC1.
AUTHOR. SIMOTIME TECHNOLOGIES.
*****************************************************************
* Copyright (C) 1987-2022 SimoTime Technologies. *
* *
* All rights reserved. Unpublished, all rights reserved under *
* copyright law and international treaty. Use of a copyright *
* notice is precautionary only and does not imply publication *
* or disclosure. *
* *
* Permission to use, copy, modify and distribute this software *
* for any non-commercial purpose and without fee is hereby *
* granted, provided the SimoTime copyright notice appear on all *
* copies of the software. The SimoTime name or Logo may not be *
* used in any advertising or publicity pertaining to the use *
* of the software without the written permission of SimoTime *
* Technologies. *
* *
* Permission to use, copy, modify and distribute this software *
* for any commercial purpose requires a fee to be paid to *
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* license will be granted for use within an enterprise, *
* provided the SimoTime copyright notice appear on all copies *
* of the software. The SimoTime name or Logo may not be used *
* in any advertising or publicity pertaining to the use of the *
* software without the written permission of SimoTime *
* Technologies. *
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*****************************************************************
* This program is provided by SimoTime Technologies *
* Our e-mail address is: helpdesk@simotime.com *
* Also, visit our Web Site at http://www.simotime.com *
*****************************************************************
*
*****************************************************************
* Source Member: ASMBITC1.CBL
* Copy Files: PASSBITS.CPY
* Calls to: ASM4BITS
*****************************************************************
*
* ASMBITC1 - Call ASM4BITS to convert between bits and bytes.
*
* CALLING PROTOCOL
* ----------------
* Use standard procedure to RUN or ANIMATE.
*
* DESCRIPTION
* -----------
* This program will call a COBOL routine to access a
* routine to convert between bits and bytes..
*
* ************
* * CBLBITJ1 *
* ********jcl*
* *
* *
* ************ ************
* * ASMBITC1 *-----* CONSOLE *
* ********cbl* ******dsply*
* *
* *
* ************
* * ASM4BITS *
* ********cbl*
*
* This program calls ASM4BITS to perform two functions:
*
* EXPAND - translate the bits of a one-byte field to bytes
* in an eight-byte field.
* COMPRESS - translate the bytes of an eight-byte field into
* bits in a one-byte field.
*
*****************************************************************
* The EXPAND function will do the following:
*
* Input: BTS-PASS-BITS, a one byte field (8-bits)
* OUTPUT: BTS-PASS-BYTES, an eight byte field
*
* For each bit that is on in the BTS-PASS-BITS field set the
* corresponding byte in the BTS-PASS-BYTES field to a value
* of one.
*
* For each bit that is off in the BTS-PASS-BITS field set the
* corresponding byte in the BTS-PASS-
* BYTES field to a value of zero.
*
* Example: if BTS-PASS-BITS = x'55'
* then BTS-PASS-BYTES will be '01010101'
*
*****************************************************************
* The COMPRESS function will do the following:
*
* Input: BTS-PASS-BYTES, an eight byte field
* Output: BTS-PASS-BITS, a one byte field (8-bits)
*
* For each byte that is a one in the BTS-PASS-BYTES field the
* corresponding bit in the BTS-PASS-BITS field is set to ON (1)
*
* For each byte that is zero in the BTS-PASS-BYTES field the
* corresponding bit in the BTS-PASS-BITS field is set to OFF (0).
*
* Example: if BTS-PASS-BYTES = '01010101'
* then BTS-PASS-BITS set to x'55'
*
*****************************************************************
*
* MAINTENANCE
* -----------
* 1989/02/27 Simmons, Created program.
* 1997/03/17 Simmons, Updated for call to ASM4BITS.
*
*****************************************************************
*
ENVIRONMENT DIVISION.
DATA DIVISION.
WORKING-STORAGE SECTION.
*****************************************************************
* Data-structure for Title and Copyright...
* ------------------------------------------------------------
01 SIM-TITLE.
05 T1 pic X(11) value '* ASMBITC1 '.
05 T2 pic X(34) value 'Convert between Bits and Bytes '.
05 T3 pic X(10) value ' v22.06.01'.
05 T4 pic X(24) value ' http://www.simotime.com'.
01 SIM-COPYRIGHT.
05 C1 pic X(11) value '* ASMBITC1 '.
05 C2 pic X(20) value 'Copyright 1987-2022 '.
05 C3 pic X(28) value ' SimoTime Technologies '.
05 C4 pic X(20) value ' All Rights Reserved'.
01 SIM-THANKS-01.
05 C1 pic X(11) value '* ASMBITC1 '.
05 C2 pic X(32) value 'Thank you for using this program'.
05 C3 pic X(32) value ' provided from SimoTime Technolo'.
05 C4 pic X(04) value 'gies'.
01 SIM-THANKS-02.
05 C1 pic X(11) value '* ASMBITC1 '.
05 C2 pic X(32) value 'Please send all inquires or sugg'.
05 C3 pic X(32) value 'estions to the helpdesk@simotime'.
05 C4 pic X(04) value '.com'.
COPY PASSBITS.
*****************************************************************
* BTS-PASS-REQUEST values when calling ASM4BITS.
* ------------------------------------------------------------
01 REQUEST-4-EXPAND pic X(8) value 'EXPAND '.
01 REQUEST-4-COMPRESS pic X(8) value 'COMPRESS'.
*****************************************************************
* Buffer used for posting messages to the console.
* ------------------------------------------------------------
01 MESSAGE-BUFFER.
05 MESSAGE-HEADER pic X(11) value '* ASMBITC1 '.
05 MESSAGE-TEXT pic X(68).
*****************************************************************
* Work fields used for testing call to ASM4BITS.
* ------------------------------------------------------------
01 HEX-00 pic X value x'00'.
01 HEX-55 pic X value x'55'.
01 HEX-AA pic X value x'AA'.
01 HEX-FF pic X value x'FF'.
01 BYTES-00 pic X(8).
01 BYTES-55 pic X(8).
01 BYTES-AA pic X(8).
01 BYTES-FF pic X(8).
01 ZERO-VALUE pic 9 value 0.
01 MINUS-ONE pic S9 value -1.
01 MINUS-ONE-X redefines MINUS-ONE
pic X.
01 POSITIVE-BIT-VALUE pic X(8) value '00000000'.
01 NEGATIVE-BIT-VALUE pic X(8) value '00000000'.
01 THREE-BYTES.
05 PACK-03 pic S9(5) comp-3 value 0.
01 TWO-BYTES pic X(2) value '00'.
01 EIGHT-BYTES pic X(8) value LOW-VALUES.
01 THE-EASY-WAY.
05 FILLER pic X(9) value 'Efficient'.
05 FILLER pic X(10) value ', PACK-03 '.
05 PACK-03-E1L pic X(4) value SPACES.
05 FILLER pic X value '-'.
05 PACK-03-E1R pic X(4) value SPACES.
05 FILLER pic X value SPACE.
05 PACK-03-E2L pic X(4) value SPACES.
05 FILLER pic X value '-'.
05 PACK-03-E2R pic X(4) value SPACES.
05 FILLER pic X value SPACE.
05 PACK-03-E3L pic X(4) value SPACES.
05 FILLER pic X value '-'.
05 PACK-03-E3R pic X(4) value SPACES.
05 FILLER pic X(13) value ', UNPACKED-5='.
05 UNPACKED-5 pic 9(5) value 0.
01 THE-HARD-WAY.
05 FILLER pic X(9) value 'Difficult'.
05 FILLER pic X(10) value ', PACK-03 '.
05 PACK-03-H1L pic X(4) value SPACES.
05 FILLER pic X value '-'.
05 PACK-03-H1R pic X(4) value SPACES.
05 FILLER pic X value SPACE.
05 PACK-03-H2L pic X(4) value SPACES.
05 FILLER pic X value '-'.
05 PACK-03-H2R pic X(4) value SPACES.
05 FILLER pic X value SPACE.
05 PACK-03-H3L pic X(4) value SPACES.
05 FILLER pic X value '-'.
05 PACK-03-H3R pic X(4) value SPACES.
05 FILLER pic X(13) value ', FIVE-BYTES='.
05 FIVE-BYTES pic X(5) value '00000'.
01 ALPHABET-UPPER pic X(26) value 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'.
01 IX-1 pic 9(3) value 0.
01 IX-2 pic 9(3) value 0.
01 IX-3 pic 9(3) value 0.
*****************************************************************
PROCEDURE DIVISION.
perform Z-POST-COPYRIGHT
perform BYTES-TO-BITS-COMPRESS.
perform BITS-TO-BYTES-EXPAND.
perform ALPHABET-DUMP.
perform COBOL-UNPACK.
perform Z-THANK-YOU.
move ZERO to RETURN-CODE
GOBACK.
*****************************************************************
ALPHABET-DUMP.
move 'Starting ALPHABET-DUMP Routine...' to MESSAGE-TEXT
perform Z-POST-MESSAGE
add 1 to ZERO giving IX-1
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
perform 26 times
move ALPHABET-UPPER(IX-1:1) to BTS-PASS-BITS
call 'ASM4BITS' using BTS-PASS-AREA
move 'Position nnn is x, the binary value is xxxx-xxxx'
to MESSAGE-TEXT
move IX-1 to MESSAGE-TEXT(10:03)
move BTS-PASS-BITS to MESSAGE-TEXT(17:1)
move BTS-PASS-BYTES(1:4) to MESSAGE-TEXT(40:4)
move BTS-PASS-BYTES(5:4) to MESSAGE-TEXT(45:4)
perform Z-POST-MESSAGE
add 1 to IX-1
end-perform
exit.
*****************************************************************
BITS-TO-BYTES-EXPAND.
move 'Starting BITS-TO-BYTES-EXPAND Routine...'
to MESSAGE-TEXT
perform Z-POST-MESSAGE
move HEX-00 to BTS-PASS-BITS
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES to BYTES-00
perform DISPLAY-BYTES
move HEX-FF to BTS-PASS-BITS
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES to BYTES-FF
perform DISPLAY-BYTES
move HEX-55 to BTS-PASS-BITS
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES to BYTES-55
perform DISPLAY-BYTES
move HEX-AA to BTS-PASS-BITS
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES to BYTES-AA
perform DISPLAY-BYTES
exit.
*****************************************************************
BYTES-TO-BITS-COMPRESS.
move 'Starting BYTES-TO-BITS-COMPRESS Routine...'
to MESSAGE-TEXT
perform Z-POST-MESSAGE
move 'USERNOTE BYTES-TO-BITS-COMPRESS 00000000...'
to MESSAGE-TEXT
perform Z-POST-MESSAGE
move '00000000' to BTS-PASS-BYTES
move REQUEST-4-COMPRESS to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BITS to HEX-00
perform DISPLAY-BYTES
move 'USERNOTE BYTES-TO-BITS-COMPRESS 11111111...'
to MESSAGE-TEXT
perform Z-POST-MESSAGE
move '11111111' to BTS-PASS-BYTES
move REQUEST-4-COMPRESS to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BITS to HEX-FF
perform DISPLAY-BYTES
move '01010101' to BTS-PASS-BYTES
move REQUEST-4-COMPRESS to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BITS to HEX-55
perform DISPLAY-BYTES
move '10101010' to BTS-PASS-BYTES
move REQUEST-4-COMPRESS to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BITS to HEX-AA
perform DISPLAY-BYTES
exit.
*****************************************************************
* If you thought the UnPack was reserved for the mainframe *
* assembler programmers then take a look at the following *
* routine. The is a bit of an esoteric use of bit mainipulation *
* but it does unpack a data string into a new data string. *
* *
* A quicker and better way to unpack a field is as follows: *
* ADD PACKED-FIELD TO ZERO GIVING UNPACKED-FIELD. *
*****************************************************************
COBOL-UNPACK.
move 'Starting the COBOL-UNPACK Routine...'
to MESSAGE-TEXT
perform Z-POST-MESSAGE
add 615 to ZERO giving PACK-03
* Do the UNPACK the easy way...
add PACK-03 to ZERO giving UNPACKED-5
* First, determine the bit configuration for zero to be
* used to set the left-nibble of the unpacked bytes.
* Then determine the negative sign bit configuration.
* This section of code is used so the program will run
* properly in both an EBCDIC and ASCII environment.
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
move ZERO-VALUE to BTS-PASS-BITS
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES to POSITIVE-BIT-VALUE
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
move MINUS-ONE-X to BTS-PASS-BITS
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES to NEGATIVE-BIT-VALUE
move '0000' to NEGATIVE-BIT-VALUE(5:4)
* Do the UNPACK the esoteric way...
move all '0' to FIVE-BYTES
add 1 to ZERO giving IX-1
add 1 to ZERO giving IX-2
add 3 to ZERO giving IX-3
perform until IX-3 = 1
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
move THREE-BYTES(IX-1:1) to BTS-PASS-BITS
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES to EIGHT-BYTES
move REQUEST-4-COMPRESS to BTS-PASS-REQUEST
move POSITIVE-BIT-VALUE to BTS-PASS-BYTES
move EIGHT-BYTES(1:4) to BTS-PASS-BYTES(5:4)
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BITS to FIVE-BYTES(IX-2:1)
add 1 to IX-2
move EIGHT-BYTES(5:4) to BTS-PASS-BYTES(5:4)
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BITS to FIVE-BYTES(IX-2:1)
subtract 1 from IX-3
add 1 to IX-2
add 1 to IX-1
end-perform
perform COBOL-UNPACK-UNITS.
* Display the results...
perform COBOL-UNPACK-POST-EFFICIENT
perform COBOL-UNPACK-POST-DIFFICULT
move 'Finished the COBOL-UNPACK Routine...'
to MESSAGE-TEXT
perform Z-POST-MESSAGE
exit.
*---------------------------------------------------------------*
COBOL-UNPACK-POST-DIFFICULT.
move THREE-BYTES(1:1) to BTS-PASS-BITS
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES(1:4) to PACK-03-H1L
move BTS-PASS-BYTES(5:4) to PACK-03-H1R
move THREE-BYTES(2:1) to BTS-PASS-BITS
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES(1:4) to PACK-03-H2L
move BTS-PASS-BYTES(5:4) to PACK-03-H2R
move THREE-BYTES(3:1) to BTS-PASS-BITS
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES(1:4) to PACK-03-H3L
move BTS-PASS-BYTES(5:4) to PACK-03-H3R
move THE-HARD-WAY to MESSAGE-TEXT
perform Z-POST-MESSAGE
exit.
*---------------------------------------------------------------*
COBOL-UNPACK-POST-EFFICIENT.
move THREE-BYTES(1:1) to BTS-PASS-BITS
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES(1:4) to PACK-03-E1L
move BTS-PASS-BYTES(5:4) to PACK-03-E1R
move THREE-BYTES(2:1) to BTS-PASS-BITS
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES(1:4) to PACK-03-E2L
move BTS-PASS-BYTES(5:4) to PACK-03-E2R
move THREE-BYTES(3:1) to BTS-PASS-BITS
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES(1:4) to PACK-03-E3L
move BTS-PASS-BYTES(5:4) to PACK-03-E3R
move THE-EASY-WAY to MESSAGE-TEXT
perform Z-POST-MESSAGE
exit.
*---------------------------------------------------------------*
COBOL-UNPACK-UNITS.
move REQUEST-4-EXPAND to BTS-PASS-REQUEST
move THREE-BYTES(IX-1:1) to BTS-PASS-BITS
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BYTES to EIGHT-BYTES
move REQUEST-4-COMPRESS to BTS-PASS-REQUEST
if PACK-03 < 0
move NEGATIVE-BIT-VALUE to BTS-PASS-BYTES
else
move POSITIVE-BIT-VALUE to BTS-PASS-BYTES
end-if
move EIGHT-BYTES(1:4) to BTS-PASS-BYTES(5:4)
* move EIGHT-BYTES(5:4) to BTS-PASS-BYTES(1:4)
call 'ASM4BITS' using BTS-PASS-AREA
move BTS-PASS-BITS to FIVE-BYTES(IX-2:1)
exit.
*****************************************************************
DISPLAY-BYTES.
move 'Binary value is ' to MESSAGE-TEXT(1:16)
move BTS-PASS-BYTES(1:4) to MESSAGE-TEXT(17:4)
move '-' to MESSAGE-TEXT(21:1)
move BTS-PASS-BYTES(5:4) to MESSAGE-TEXT(22:4)
perform Z-POST-MESSAGE
exit.
*****************************************************************
* The following Z-Routines perform administrative tasks *
* for this program. *
*****************************************************************
*****************************************************************
Z-POST-COPYRIGHT.
display SIM-TITLE
display SIM-COPYRIGHT
exit.
*****************************************************************
Z-POST-MESSAGE.
display MESSAGE-BUFFER
move SPACES to MESSAGE-TEXT
exit.
*****************************************************************
Z-THANK-YOU.
display SIM-THANKS-01
display SIM-THANKS-02
exit.
*****************************************************************
* This example is provided by SimoTime Technologies *
* Our e-mail address is: helpdesk@simotime.com *
* Also, visit our Web Site at http://www.simotime.com *
*****************************************************************
Assembler Bit Processing Routine
This program (ASM4BITS.mlc) was originally written to be used as a teaching and learning aid. Application programs that are being migrated to a Windows, UNIX or Linux System a callable COBOL program is used to replace this callable 370 assembler routine. Today, the callable COBOL program is used in a number of mainframe shops and it is the program of choice used by SimoTime. Also, the program has been tested and deployed on a Windows System with Enterprise Developer from Micro Focus.
ASM4BITS CSECT
***********************************************************************
* ASM4BITS.MLC - This is an HLASM Program *
* Provided by SimoTime Technologies *
* (C) Copyright 1987-2019 All Rights Reserved *
* Web Site URL: http://www.simotime.com *
* e-mail: helpdesk@simotime.com *
***********************************************************************
* *
* Created: 1974/06/01, Simmons *
* Changed: 1974/06/01, Simmons, no changes to date... *
* *
***********************************************************************
* *
* This program will run on an IBM Mainframe using MVS or a PC using *
* Micro Focus Mainframe Express, version 2.5 or later (MFE) with *
* the Assembler Option. *
* *
* This program provides an example of an assembler sub-routine that *
* provides an eight-byte string of zeroes or ones to coincide with *
* the bits in a single byte. *
* *
* Using the Micro Focus Animation You can immediately see the results *
* of each instruction execution. This is a very effective way to *
* become familiar with how these techniques work. *
* *
***********************************************************************
*
* This program is a callable routine that performs two functions:
*
* EXPAND - translate the bits of a one-byte field to bytes
* in an eight-byte field.
* COMPRESS - translate the bytes of an eight-byte field into
* bits in a one-byte field.
*
* ------------------------------------------------------------------- *
* The EXPAND function will do the following.
*
* The call interface is as follows.
* move 'EXPAND ' to BTS-PASS-REQUEST
* call 'ASM4BITS' using BTS-PASS-AREA
*
* Input: BTS-PASS-BITS, a one byte field (8-bits)
* OUTPUT: BTS-PASS-BYTES, an eight byte field
*
* For each bit that is on in the BTS-PASS-BITS field set the
* corresponding byte in the BTS-PASS-BYTES field to a value
* of one.
*
* For each bit that is off in the BTS-PASS-BITS field set the
* corresponding byte in the BTS-PASS-
* BYTES field to a value of zero.
*
* Example: if BTS-PASS-BITS = x'55'
* then BTS-PASS-BYTES will be '01010101'
*
* ------------------------------------------------------------------- *
* The COMPRESS function will do the following:
*
* The call interface is as follows.
* move 'COMPRESS' to BTS-PASS-REQUEST
* call 'ASM4BITS' using BTS-PASS-AREA
*
* Input: BTS-PASS-BYTES, an eight byte field
* Output: BTS-PASS-BITS, a one byte field (8-bits)
*
* For each byte that is a one in the BTS-PASS-BYTES field the
* corresponding bit in the BTS-PASS-BITS field is set to ON (1)
*
* For each byte that is zero in the BTS-PASS-BYTES field the
* corresponding bit in the BTS-PASS-BITS field is set to OFF (0).
*
* Example: if BTS-PASS-BYTES = '01010101'
* then BTS-PASS-BITS set to x'55'
*
***********************************************************************
* ASM4BITS, Expand or compress between bits and bytes. *
***********************************************************************
*
R0 EQU 0
R1 EQU 1
R2 EQU 2
R3 EQU 3
R4 EQU 4
R5 EQU 5
R6 EQU 6
R7 EQU 7
R8 EQU 8
R9 EQU 9
R10 EQU 10
R11 EQU 11
R12 EQU 12
R13 EQU 13
R14 EQU 14
R15 EQU 15
*
* ------------------------------------------------------------------- *
SAVE (14,12)
BALR 12,0
USING *,12
*
ST R1,SAVER1 * Save Register 1
L R8,0(,R1) * Get address of PASS AREA
L R6,0(,R1)
LA R6,12(,R6) * Get address of Single Byte
L R7,0(,R1)
LA R7,13(,R7) * Get address of eight bytes
*
CLC 0(8,R8),REQEXP * Is this an EXPAND request...
BE EXPAND
*
CLC 0(8,R8),REQCOM * Is this a COMPRESS request...
BE COMPRESS
*
B EORNOK
*
* ------------------------------------------------------------------- *
* Based on the bit within a one-byte field being set to "OFF" or "ON"
* move a "0" or "1" value to the corresponding byte within an
* eight-byte string.
*
EXPAND EQU *
MVC WRK04+3(1),0(R6) * Save the one-byte
MVC 0(8,R7),ZEROES * Init eight-byte string to zeroes
LA R5,128
LA R3,8 * Load 8 into REG-3 for loop count
BCTLOOP1 EQU *
L R4,WRK04
NR R4,R5 * Logical and of bit position
BZ *+8
MVI 0(,R7),C'1' * Move one if bit on
LA R7,1(,R7) * Incr to Next Byte String Address
SRL R5,X'01' * Shift right 1-bit position
BCT R3,BCTLOOP1 * Loop until REG-3 goes to ZERO
B RETURN
*
* ------------------------------------------------------------------- *
* Based on a "0" or "1" value of an individual byte within an
* eight-byte string set the corresponding bit within a one-byte field
* to "OFF" or "ON".
*
COMPRESS EQU *
MVI 0(,R6),X'00' * Init the one-byte to low-value
LA R5,128
LA R3,8 * Load 8 into REG-3 for loop count
SR R4,R4
BCTLOOP2 EQU *
CLI 0(,R7),C'1' * Is eight-byte position a one
BNE *+6
OR R4,R5 * Set bit if value is one
LA R7,1(,R7) * Incr to Next Byte String Address
SRL R5,X'01' * Shift right 1-bit position
BCT R3,BCTLOOP2 * Loop until REG-3 goes to ZERO
ST R4,WRK04 * Store the one-byte value
MVC 0(1,R6),WRK04+3 * Move one-byte to PASS AREA
B RETURN
*
* ------------------------------------------------------------------- *
* Success, return to the calling program with a ZERO Return Code.
*
RETURN EQU *
SR 15,15 * Set return code to ZERO
RETURN (14,12),RC=(15)
*
* ------------------------------------------------------------------- *
* ABENDing, return to the calling program with a non-ZERO Return Code.
*
EORNOK EQU *
LA R15,16 * Set return code to 16 or x'10'
RETURN (14,12),RC=(15)
*
* ------------------------------------------------------------------- *
* Data buffers used within the routine.
*
REQEXP DC CL8'EXPAND '
REQCOM DC CL8'COMPRESS'
SAVER1 DC 4XL1'00'
WRK04 DC 4XL1'00'
ZEROES EQU *
ZERO DC CL1'0'
DC 7CL1'0'
END
COBOL Copy File for Pass Area
This copy file (PASSBITS.cpy) provides a convenient method for defining the data areas (or fields) that are used to pass information between the demo program and the bit and byte conversion routine.
*****************************************************************
* PASSBITS is a COBOL Copy File *
* Data Structure or Pass Area used for calling SIMOBITS. *
* Copyright (C) 1987-2019 SimoTime Technologies *
* All Rights Reserved *
*****************************************************************
* Provided by SimoTime Technologies *
* Our e-mail address is: helpdesk@simotime.com *
* Also, visit our Web Site at http://www.simotime.com *
*****************************************************************
*
* When BTS-PASS-REQUEST is 'EXPAND ' do analysis of
* BTS-PASS-BITS (a 1-btye field of 8-bits)
* and based on the bit settings a corresponding value of
* 0 or 1 is set in the BTS-PASS-BYTES (an 8-byte field
* of zeroes and ones).
*
* When BTS-PASS-REQUEST is 'COMPRESS' do analysis of
* BTS-PASS-BYTES (an 8-byte field of zeroes and ones)
* and based on a value of 0 or 1 the corresponding
* bit in BTS-PASS-BITS (a 1-byte field of 8-bits) is
* switched ON or OFF.
*
01 BTS-PASS-AREA.
05 BTS-PASS-REQUEST PIC X(8).
05 BTS-PASS-RESULT PIC S9(9) COMP.
05 BTS-PASS-RECORD.
10 BTS-PASS-BITS PIC X.
10 BTS-PASS-BYTES.
15 BTS-PASS-BYTE-01 PIC X.
15 BTS-PASS-BYTE-02 PIC X.
15 BTS-PASS-BYTE-03 PIC X.
15 BTS-PASS-BYTE-04 PIC X.
15 BTS-PASS-BYTE-05 PIC X.
15 BTS-PASS-BYTE-06 PIC X.
15 BTS-PASS-BYTE-07 PIC X.
15 BTS-PASS-BYTE-08 PIC X.
*
*** PASSBITS - End-of-Copy File - - - - - - - - - - - PASSBITS *
*****************************************************************
*
Summary
This suite of programs is provided as a COBOL program that calls an Assembler routine. It is an example of one of the possible solutions to the problem of determining and changing the bits within a byte. This example uses an approach of converting the bit information in a single byte to or from an eight-byte field of COBOL accessible zeroes and ones. This document may be used to assist as a tutorial for new programmers or as a quick reference for experienced programmers.
In the world of programming there are many ways to solve a problem. This documentation and software were developed and tested on systems that are configured for a SIMOTIME environment based on the hardware, operating systems, user requirements and security requirements. Therefore, adjustments may be needed to execute the jobs and programs when transferred to a system of a different architecture or configuration.
SIMOTIME Services has experience in moving or sharing data or application processing across a variety of systems. For additional information about SIMOTIME Services or Technologies please contact us using the information in the Contact or Feedback section of this document.
Software Agreement and Disclaimer
Permission to use, copy, modify and distribute this software, documentation or training material for any purpose requires a fee to be paid to SimoTime Technologies. Once the fee is received by SimoTime the latest version of the software, documentation or training material will be delivered and a license will be granted for use within an enterprise, provided the SimoTime copyright notice appear on all copies of the software. The SimoTime name or Logo may not be used in any advertising or publicity pertaining to the use of the software without the written permission of SimoTime Technologies.
SimoTime Technologies makes no warranty or representations about the suitability of the software, documentation or learning material for any purpose. It is provided "AS IS" without any expressed or implied warranty, including the implied warranties of merchantability, fitness for a particular purpose and non-infringement. SimoTime Technologies shall not be liable for any direct, indirect, special or consequential damages resulting from the loss of use, data or projects, whether in an action of contract or tort, arising out of or in connection with the use or performance of this software, documentation or training material.
Downloads and Links
This section includes links to documents with additional information that are beyond the scope and purpose of this document. The first group of documents may be available from a local system or via an internet connection, the second group of documents will require an internet connection.
Note: A SimoTime License is required for the items to be made available on a local system or server.
Current Server or Internet Access
The following links may be to the current server or to the Internet.
Explore Bit Manipulation using a COBOL program calling COBOL to do the accessing of individuals bits within a byte.
Explore How to do a logical AND Function using a COBOL program that calls a COBOL routine to do the actual logical AND of two data strings.
Explore How to do a logical OR Function using a COBOL program that calls a COBOL routine to do the actual logical OR of two data strings.
Explore How to do an Exclusive OR (XOR) using a COBOL program that calls a COBOL routine to do the actual XOR of two data strings.
Explore the COBOL Connection for more examples of COBOL programming techniques and sample code.
Explore The ASCII and EBCDIC Translation Tables. These tables are provided for individuals that need to better understand the bit structures and differences of the encoding formats.
Explore The File Status Return Codes that are used to interpret the results of accessing VSAM data sets and/or QSAM files.
Internet Access Required
The following links will require an internet connect.
This suite of programs and documentation is available for download. Link to an Evaluation zPAK Option that includes the program members, documentation and control files.
A good place to start is The SimoTime Home Page for access to white papers, program examples and product information. This link requires an Internet Connection
Explore The Micro Focus Web Site for more information about products (including Micro Focus COBOL) and services available from Micro Focus. This link requires an Internet Connection.
Glossary of Terms
Explore the Glossary of Terms for a list of terms and definitions used in this suite of documents and white papers.
Contact or Feedback
This document was created and is maintained by SimoTime Technologies. If you have any questions, suggestions, comments or feedback please use the following contact information.
| 1. | Send an e-mail to our helpdesk. |
| 1.1. | helpdesk@simotime.com. |
| 2. | Our telephone numbers are as follows. |
| 2.1. | 1 415 763-9430 office-helpdesk |
| 2.2. | 1 415 827-7045 mobile |
We appreciate hearing from you.
Company Overview
SimoTime Technologies was founded in 1987 and is a privately owned company. We specialize in the creation and deployment of business applications using new or existing technologies and services. We have a team of individuals that understand the broad range of technologies being used in today's environments. Our customers include small businesses using Internet technologies to corporations using very large mainframe systems.
Quite often, to reach larger markets or provide a higher level of service to existing customers it requires the newer Internet technologies to work in a complementary manner with existing corporate mainframe systems. We specialize in preparing applications and the associated data that are currently residing on a single platform to be distributed across a variety of platforms.
Preparing the application programs will require the transfer of source members that will be compiled and deployed on the target platform. The data will need to be transferred between the systems and may need to be converted and validated at various stages within the process. SimoTime has the technology, services and experience to assist in the application and data management tasks involved with doing business in a multi-system environment.
Whether you want to use the Internet to expand into new market segments or as a delivery vehicle for existing business functions simply give us a call or check the web site at http://www.simotime.com
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