Re: COBOL Bit Manipulation

[Jason Abreu <jason.abreu@xxxxxxxxxxxxxxxxxxxx>]

I came up with a solution.
Instead of trying to work with individual bits in a binary format, I 
used the decimal format to manipulate the bits, since I know how many 
bytes I am working with (1).
I should note I am only interested in setting the bits, not reading the 
bits.

Example:

01       WORK-AREA.
  05     FIELD-OF-INDICATORS-2.
    10   FILLER                   PIC  X(01).
    10   FIELD-OF-IND             PIC  X(01).
  05     DEC-IND      REDEFINES   FIELD-OF-INDICATORS-2
                                  PIC  9(04)  BINARY.

01       BIT-VALUES.
  05     BIT-1                    PIC  9(04)  BINARY  VALUE   1.
  05     BIT-2                    PIC  9(04)  BINARY  VALUE   2.
  05     BIT-3                    PIC  9(04)  BINARY  VALUE   4.
  05     BIT-4                    PIC  9(04)  BINARY  VALUE   8.
  05     BIT-5                    PIC  9(04)  BINARY  VALUE  16.
  05     BIT-6                    PIC  9(04)  BINARY  VALUE  32.
  05     BIT-7                    PIC  9(04)  BINARY  VALUE  64.
  05     BIT-8                    PIC  9(04)  BINARY  VALUE 128.

...
PROCEDURE DIVISION
...

  MOVE   ZEROES                   TO   DEC-IND.
  IF     SWITCH-1                 =    'Y'
    ADD  BIT-8                    TO   DEC-IND
  END-IF.
  IF     SWITCH-2                 =    'Y'
    ADD  BIT-7                    TO   DEC-IND
  END-IF.
  IF     SWITCH-3                 =    'Y'
    ADD  BIT-6                    TO   DEC-IND
  END-IF.

  MOVE   FIELD-OF-IND             TO   SOME-FIELD-TO-STORE-OR-USE.
...


Jason Abreu
Abreu Innovations, Inc.
jason.abreu@xxxxxxxxxxxxxxxxxxxx
http://www.abreuinnovations.com/

On 1/12/2011 3:19 PM, Jon Paris wrote:
> Well Pic 1 means a single byte indicator so that won't help.
>
> It is years since I did this but in the pre-ILE days I did it with a simple divide/multiply routine. Don't have a sample of the code handy but it is not hard to do. Depending on what you want, you can either divide by the appropriate power of 2 to shift the bit in question to the least significant position, then divide by 2 to isolate the bit in question (in the remainder) change that value as you wish and reverse the process.
>
> If you want to test/set any arbitrary bit then it is easier to just use a divide by 2 loop and store the remainders in an array. Test/change as desired and rebuild by a repetitive multiply loop.
>
> These days I would code it in RPGIV and use the bit oriented functions in RPG IV to do the work. Then call the RPGIV routine form the COBOL code - probably much easier.
>
>
> Jon Paris
>
> www.Partner400.com
> www.SystemiDeveloper.com
>
>
>
> On Jan 12, 2011, at 2:59 PM, Jason Abreu wrote:
>
> > Does anybody have experience with bit manipulation in COBOL?
> >
> > I would like to be able to switch individual bits on/off in a single byte.
> >
> > I imagined something like:
> >
> > 01        WORK.
> >    05      CHAR-BYTE      PIC X(01)    VALUE X'40'.
> >    05      BINARY-REP     REDEFINES    CHAR-BYTE.
> >      10    BIT-1          PIC 1.
> >        88  BIT-1-ON                    VALUE B'1'.
> >        88  BIT-1-OFF                   VALUE B'1'.
> >      ... repeat for all 8 bits.
> >
> >
> > So usage could be something like
> >
> > SET BIT-1-ON TO TRUE.
> > MOVE CHAR-BYTE TO FILE-FIELD.
> >
> > Any ideas on this?
> > Thanks, ahead of time!
> > --
> > Jason Abreu
> > Abreu Innovations, Inc.
> > jason.abreu@xxxxxxxxxxxxxxxxxxxx
> > http://www.abreuinnovations.com/
> > --
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