Re: COBOL Bit Manipulation

[CRPence <CRPbottle@xxxxxxxxx>]

On 1/12/11 11:59 AM, 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?

  I would avoid using bits if bytes could be used instead, simply 
because there is so much more value in human understood tokens to 
represent what might otherwise be represented by bit-on and bit-off.  A 
COBOL program is hardly going to be like a slim assembler routine ;-) so 
bytes versus bits is rarely an issue.  If absolutely required to use 
bits however, ...

  I would use a different ILE language which has good bitwise 
manipulation statements, to create a module to do what is required.  Or 
perhaps for keeping the logic effectively inline [aside from requiring 
pre-compiler], I would use the SQL bit-wise logical scalar functions; 
e.g. using LOR and LAND, something like the following:

  EXEC SQL VALUES LOR( :"CHAR-BYTE" , X'80' )
           INTO :"CHAR-BYTE"

Regards, Chuck