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rakesh_mishra18
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Joined: 15 May 2006
Posts: 23
Location: Jamshedpur
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| Is Bit level operation possible in Cobol. Pls provide some example. |
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Anuj Dhawan
Superior Member
Joined: 22 Apr 2006
Posts: 6250
Location: Mumbai, India
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Hello Rakesh,
You seem to have two differnt question, when you have differnt questions you should have differnt threads, per forum rules. Your other question in this thread is been spiltted to
Need to know limitaion of REXX over JCL.
-Ad |
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Robert Sample
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Joined: 06 Jun 2008
Posts: 8696
Location: Dubuque, Iowa, USA
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| Have you read the manual? |
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Anuj Dhawan
Superior Member
Joined: 22 Apr 2006
Posts: 6250
Location: Mumbai, India
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mmwife
Super Moderator
Joined: 30 May 2003
Posts: 1592
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Hi Rakesh,
I wrote the following as an exercise some time back. It should give you an idea of how to manipulate the individual bits in a byte.
| Code: |
IDENTIFICATION DIVISION.
PROGRAM-ID. BITFLIPR.
AUTHOR. JACK.
ENVIRONMENT DIVISION.
******************************************************************
* CHANGES THE REQUESTED BIT OF THE BYTE PASSED BY THE CALLER. *
* THIS SUB PGM CAN BE CALLED FROM A PGM OR EXECUTED DIRECTLY *
* FROM JCL USING THE PARM FIELD IN THE EXEC CARD. THE JCL EX- *
* ECUTION IS INTENDED TO FACILITATE TESTING. *
* *
* WHEN INVOKED FROM A PGM, USE 1 OF THE FOLLOWING CALLING SEQ: *
* *
* CALL 'BITFLIPR' USING LK-PARM-LEN LK-PARM-DTA *
* CALL WS-PGMNAME USING LK-PARM-LEN LK-PARM-DTA *
* *
* WHERE, *
* *
* WS-PGMNAME CONTAINS THE 8 POSITION LITERAL 'BITFLIPR'. *
* LK-PARM-LEN IS AN 01 LEVEL DEFINED AS IN THE TABLE BELOW. *
* LK-PARM-DTA IS AN 01 LEVEL DEFINED AS FOLLOWS: *
* *
* 01 LK-PARM-DATA. *
* 05 LK-TGT-BYTE *
* 05 LK-BIT-NBR *
* 05 LK-ACTION *
* *
* WHERE THE 05 LEVELS ARE DEFINED AS IN THE TABLE BELOW. *
* *
* DESCRIPTION PICTURE COMMENTS *
* ************* ********** **************************
* PARM LENGTH S9(4) COMP CALLED FROM PGM THIS FLD *
* MUST HAVE VALUE OF -1. *
* CALLED FROM JCL THIS FLD *
* MUST BE OMMITTED. *
* TARGET BYTE X(1) THE BYTE THE CALLER *
* WANTS CHANGED. *
* BIT NUMBER 9(1) THE BIT THE CALLER *
* WANTS CHANGED. BIT NUM- *
* BERS RANGE FROM 1 TO 8 *
* FROM HI TO LOW ORDER. *
* ACTION X(1) THIS FLD HAS 1 OF 3 VAL- *
* UES: "1" - TURN BIT ON *
* "0" - TURN BIT OFF *
* "F" - FLIP THE BIT *
* *
* REMEMBER THAT THE TARGET BYTE IS UPDATED BY 'BITFLIPR'. *
* *
******************************************************************
CONFIGURATION SECTION.
DATA DIVISION.
FILE SECTION.
******************************************************************
WORKING-STORAGE SECTION.
******************************************************************
******************************************************************
01 WS-TABLES.
******************************************************************
******************************************************************
* *
* THIS TABLE IS USED TO DETERMINE THE VALUE THAT THE SUBJECT *
* BYTE MUST BE MULTIPLIED BY (MULT-VALUE) TO DETERMINE IF IT IS *
* CURRENTLY ON OR OFF (1 OR 0). *
* *
* THE TABLE IS ALSO USED TO DETERMINE THE INCREMENT/DECREMENT *
* REQUIRED TO TURN THE BIT ON OR OFF (ADD-SUB-VALUE). *
* *
******************************************************************
05 MULT-ADD-SUB-VALUES.
10 BIT1-MULT-VALUE PIC S9(004) VALUE +0 COMP.
10 BIT1-ADD-SUB-VALUE PIC S9(004) VALUE +128 COMP.
10 BIT2-MULT-VALUE PIC S9(004) VALUE +2 COMP.
10 BIT2-ADD-SUB-VALUE PIC S9(004) VALUE +64 COMP.
10 BIT3-MULT-VALUE PIC S9(004) VALUE +4 COMP.
10 BIT3-ADD-SUB-VALUE PIC S9(004) VALUE +32 COMP.
10 BIT4-MULT-VALUE PIC S9(004) VALUE +8 COMP.
10 BIT4-ADD-SUB-VALUE PIC S9(004) VALUE +16 COMP.
10 BIT5-MULT-VALUE PIC S9(004) VALUE +16 COMP.
10 BIT5-ADD-SUB-VALUE PIC S9(004) VALUE +8 COMP.
10 BIT6-MULT-VALUE PIC S9(004) VALUE +32 COMP.
10 BIT6-ADD-SUB-VALUE PIC S9(004) VALUE +4 COMP.
10 BIT7-MULT-VALUE PIC S9(004) VALUE +64 COMP.
10 BIT7-ADD-SUB-VALUE PIC S9(004) VALUE +2 COMP.
10 BIT8-MULT-VALUE PIC S9(004) VALUE +128 COMP.
10 BIT8-ADD-SUB-VALUE PIC S9(004) VALUE +1 COMP.
05 REDEFINES MULT-ADD-SUB-VALUES.
10 BIT-ARITH-ENTRY OCCURS 8 TIMES.
20 MULT-VALUE PIC S9(004).
20 ADD-SUB-VALUE PIC S9(004).
******************************************************************
01 WS-WORK-FIELDS.
******************************************************************
05 COMPARE-WRK-FLD PIC S9(004) VALUE 0 COMP.
05 REDEFINES COMPARE-WRK-FLD.
10 FILLER PIC X(001).
10 COMPARE-WRK-BYTE PIC X(001).
88 BIT-IS-ON VALUE X'80' THRU X'FF'.
88 BIT-IS-OFF VALUE X'00' THRU X'7F'.
05 ADD-SUB-WRK-FLD PIC S9(004) VALUE 0 COMP.
05 REDEFINES ADD-SUB-WRK-FLD.
10 FILLER PIC X(001).
10 ADD-SUB-WRK-BYTE PIC X(001).
1 /
******************************************************************
LINKAGE SECTION.
******************************************************************
01 LK-PARM-LEN PIC S9(004).
88 LK-EXECUTED-FROM-PGM VALUE -1.
88 LK-EXECUTED-FROM-JCL VALUE +0 THRU +9999.
01 LK-PARM-DATA.
05 LK-TGT-BYTE PIC X(001).
05 LK-BIT-NBR PIC 9(001).
88 VALID-BIT-NBR VALUE +1 THRU +8.
05 LK-ACTION PIC X(001).
88 LK-TURN-BIT-ON VALUE '1'.
88 LK-TURN-BIT-OFF VALUE '0'.
88 LK-FLIP-THE-BIT VALUE 'F'.
88 VALID-ACTION VALUE '1' '0' 'F'.
1 /
******************************************************************
PROCEDURE DIVISION USING LK-PARM-LEN LK-PARM-DATA
******************************************************************
000-MAINLINE.
******************************************************************
PERFORM 8000-VALIDATE-PARM-INFO
IF RETURN-CODE = ZEROS
PERFORM 1000-MODIFY-BIT-VALUE
ELSE
IF LK-EXECUTED-FROM-JCL
DISPLAY 'ERROR IN THE PARM LIST. RETURN CODE SHOWS '
'THE PARM# IN ERROR'
DISPLAY ' '
DISPLAY 'RETURN CODE >' RETURN-CODE '<'
END-IF
END-IF
GOBACK
.
******************************************************************
1000-MODIFY-BIT-VALUE.
******************************************************************
*===> SAVE TARGET BYTE
*---------------------------------------------------------------
MOVE LK-TGT-BYTE TO COMPARE-WRK-BYTE
MOVE LK-TGT-BYTE TO ADD-SUB-WRK-BYTE
*---------------------------------------------------------------
*===> ISOLATE BIT TO BE CHANGED. MULTIPLY THE TGT BYTE BY THE
*===> BINARY VALUE IN THE TABLE (POINTED TO BY THE BIT NUMBER
*===> PASSED BY THE CALLER). THIS MOVES THE TGT BIT TO THE HI
*===> ORDER POS OF THE WRK BYTE.
*---------------------------------------------------------------
COMPUTE COMPARE-WRK-FLD = COMPARE-WRK-FLD
* MULT-VALUE(LK-BIT-NBR)
*---------------------------------------------------------------
*===> CHANGE THE BIT AS DIRECTED BY THE ACTION FLD PROVIDED BY
*===> CALLER.IF THE BYTE VALUE OF COMPARE-WRK-BYTE IS > X'7F',
*===> THE REQUESTED BIT IS ONE;IF <= THE BIT IS ZERO.
*===> ADD TABLE VALUE IF BIT IS ZERO(OFF); SUB IF IT'S ONE(ON).
*===> THIS PREVENTS CHANGES TO SURROUNDING BITS WHILE CHANGING
*===> THE REQUESTED BIT.
*---------------------------------------------------------------
EVALUATE TRUE
WHEN LK-TURN-BIT-ON
IF BIT-IS-OFF
COMPUTE ADD-SUB-WRK-FLD = ADD-SUB-WRK-FLD
+ ADD-SUB-VALUE(LK-BIT-NBR)
END-IF
WHEN LK-TURN-BIT-OFF
IF BIT-IS-ON
COMPUTE ADD-SUB-WRK-FLD = ADD-SUB-WRK-FLD
- ADD-SUB-VALUE(LK-BIT-NBR)
END-IF
WHEN LK-FLIP-THE-BIT
IF BIT-IS-ON
COMPUTE ADD-SUB-WRK-FLD = ADD-SUB-WRK-FLD
- ADD-SUB-VALUE(LK-BIT-NBR)
ELSE
COMPUTE ADD-SUB-WRK-FLD = ADD-SUB-WRK-FLD
+ ADD-SUB-VALUE(LK-BIT-NBR)
END-IF
END-EVALUATE
*---------------------------------------------------------------
*===> IF SUBPGM WAS EXECUTED FROM JCL, I.E. A TEST, DISPLAY
*===> THE BEFORE AND AFTER VALUES OF THE TARGET FIELD. ELSE
*===> MOVE IT TO THE LINKAGE FIELD FOR RETURN TO THE CALLER.
*---------------------------------------------------------------
IF LK-EXECUTED-FROM-JCL
DISPLAY 'THE TARGET BYTE WAS CHANGED FROM >'
LK-TGT-BYTE '< TO >' ADD-SUB-WRK-BYTE '<'
ELSE
MOVE ADD-SUB-WRK-BYTE TO LK-TGT-BYTE
END-IF
.
******************************************************************
8000-VALIDATE-PARM-INFO.
******************************************************************
EVALUATE TRUE
WHEN LK-BIT-NBR NOT NUMERIC
WHEN NOT VALID-BIT-NBR
MOVE 3 TO RETURN-CODE
WHEN NOT VALID-ACTION
MOVE 4 TO RETURN-CODE
END-EVALUATE
.
*===> END OF PGM CODE |
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Kevin Wailes
New User
Joined: 29 Aug 2008
Posts: 10
Location: UK
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| There are LE callable services which allow for bit manipulation. Look in the LE programming guide. |
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Bill O'Boyle
CICS Moderator
Joined: 14 Jan 2008
Posts: 2501
Location: Atlanta, Georgia, USA
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It's easy enough to do with binary arithmetic. Move your value to a binary-fullword, which is also redefined as a PIC X(04). Then, determine which bit you'd like to check.
For example, if you need to check the 2nd-bit from the left, multiply the fullword by 2 and then check the 4th-byte of the fullword for a value greater than X'7F' (a poor man's "TM").
If it is on and you want to turn it off, then subtract 64 from the fullword (a poor man's "AND").
If it is off and you want to turn it on, then add 64 to the fullword (a poor man's "OR").
Because of the affect the TRUNC option can have on non COMP-5 halfword's, always use a fullword.
Although the TRUNC option does not have any affect on COMP-5 (Native Binary), always use a fullword.
HTH....
Regards,
Bill |
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Bill O'Boyle
CICS Moderator
Joined: 14 Jan 2008
Posts: 2501
Location: Atlanta, Georgia, USA
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One tidbit which I need to point out is the fullword is a workarea and turning bits on and off via addition and subtraction needs to be performed against the original value, which had been moved to a more "permanent" fullword-area, different than the fullword-workarea.
Regards,
Bill |
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zos5415
New User
Joined: 29 Aug 2008
Posts: 18
Location: China
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| Code: |
05 MULT-ADD-SUB-VALUES.
10 BIT1-MULT-VALUE PIC S9(004) VALUE +0 COMP. ==> it should be 1 , right ?
10 BIT1-ADD-SUB-VALUE PIC S9(004) VALUE +128 COMP.
10 BIT2-MULT-VALUE PIC S9(004) VALUE +2 COMP.
10 BIT2-ADD-SUB-VALUE PIC S9(004) VALUE +64 COMP.
10 BIT3-MULT-VALUE PIC S9(004) VALUE +4 COMP.
10 BIT3-ADD-SUB-VALUE PIC S9(004) VALUE +32 COMP.
10 BIT4-MULT-VALUE PIC S9(004) VALUE +8 COMP.
10 BIT4-ADD-SUB-VALUE PIC S9(004) VALUE +16 COMP.
10 BIT5-MULT-VALUE PIC S9(004) VALUE +16 COMP.
10 BIT5-ADD-SUB-VALUE PIC S9(004) VALUE +8 COMP.
10 BIT6-MULT-VALUE PIC S9(004) VALUE +32 COMP.
10 BIT6-ADD-SUB-VALUE PIC S9(004) VALUE +4 COMP.
10 BIT7-MULT-VALUE PIC S9(004) VALUE +64 COMP.
10 BIT7-ADD-SUB-VALUE PIC S9(004) VALUE +2 COMP.
10 BIT8-MULT-VALUE PIC S9(004) VALUE +128 COMP.
10 BIT8-ADD-SUB-VALUE PIC S9(004) VALUE +1 COMP.
05 REDEFINES MULT-ADD-SUB-VALUES.
10 BIT-ARITH-ENTRY OCCURS 8 TIMES.
20 MULT-VALUE PIC S9(004). ==> it should be comp type?
20 ADD-SUB-VALUE PIC S9(004). ==> it should be comp type?
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