Re: [MI400] Is there an easy way to scan for bits?

[Harry Williams <planesmart@xxxxxxxxxxxx>]

How would you access the table? By the way. CCITT is used for FAX and is one
of the tiff compressions.

Leif Svalgaard wrote:

> From: Steve Richter <srichter@AutoCoder.com>
> > Leif,
> > I find your solution intriguing, but I cant think anymore today unless I
> get
> > paid for it. So I cant verify it.
> > Could you show how it would work with Harry's data:
> >
> > "As an example. I start reading the bits, and if I
> > read  00110101 then I translate it to the number 0.  If I read 000111 I
> > translate it to 1,  0111 translates to 2, 1000 goes to 3, 10011 is 8,
> > ..... 0100111 translates to 18.   There is about 100 of these codes."
> >
> > And Harry, could you post more of the codes and their resulting values ?
> >
>
> here is a sketch, it need be fleshed out with more values.
> Also, there need be some code to shift the bits over and
> to get new bits from the source:
>
> DCL DD BITS CHAR(12);
> DCL DD NBR  BIN(2);
>
> TOP:        TSTBUM(B)   BITS, X'80'/ONES(L1);
> L0:         TSTBUM(B)   BITS, X'40'/ONES(L01);
> L00:        TSTBUM(B)   BITS, X'20'/ONES(L001);
> L000:       TSTBUM(B)   BITS, X'10'/ONES(L0001);
> L0000:      /* ... */
>
> L0001:      TSTBUM(B)   BITS, X'08'/ONES(L00011);
> L00010:     /* ... */
>
> L00011:     TSTBUM(B)   BITS, X'04'/ONES(L000111);
> L000110:    /* ... */
>
> L000111:    CPYNV(B)    NBR, 1/POS(DONE);
>
> L01:        TSTBUM(B)   BITS, X'20'/ONES(L011);
> L010:       TSTBUM(B)   BITS, X'10'/ONES(L0101);
> L0100:      TSTBUM(B)   BITS, X'08'/ONES(L01001);
> L01000:     /* ... */
>
> L01001:     TSTBUM(B)   BITS, X'04'/ONES(L010011);
> L010010:    /* ... */
>
> L010011:    TSTBUM(B)   BITS, X'02'/ONES(L0100111);
> L0100110:   /* ... */
>
> L0100111:   CPYNV(B)    NBR, 18/POS(DONE);
>
> L001:       TSTBUM(B)   BITS, X'20'/ONES(L0011);
> L0010:      /* ... */
>
> L0011:      TSTBUM(B)   BITS, X'08'/ONES(L00111);
> L00110:     TSTBUM(B)   BITS, X'04'/ONES(L001101);
> L00001:     /* ... */
>
> L001101:    TSTBUM(B)   BITS, X'02'/ONES(L0011010);
> L0011010:   TSTBUM(B)   BITS, X'01'/ONES(L00110101);
> L00110100:  ...
> L00110101:  CPYNV(B)    NBR, 0/ZER(DONE);
>
> /* ... */
>
> L1:         TSTBUM(B)   BITS, X'40'/ONES(L11);
> L10:        TSTBUM(B)   BITS, X'20'/ONES(L101);
> L100:       TSTBUM(B)   BITS, X'10'/ONES(L1001);
> L1000:      CPYNV(B)    NBR, 3/POS(DONE);
>
> L1001:      TSTBUM(B)   BITS, X'08'/ONES(L10011);
> L10010:     /* ... */
>
> L10011:     CPYNV(B),   NBR, 8/POS(DONE);
>
> /* ... */
>
> DONE:
>
> Another fast way would be to have a table with 2^12 entries
> in it. Then simply use the 12 bits as an index to get the number
> (and the shift).
>
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