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deepeshk79 · Posted: Fri Sep 03, 2004 5:46 am Post subject: Sort fields

Hi,

I have 3 packed fields declared in the following way

VARA START-1, LENGTH=1, TYPE=PD
VARB START-2, LENGTH=3, TYPE=PD
VARC START-5, LENGTH=3, TYPE=PD

Total = 1+3+3=7 bytes

I have two sort cards
==========================
SORT FIELDS=(1,7,PD,A)
==========================

==========================
SORT FIELDS=(1,1,PD,A,2,3,PD,A,5,3,PD,A)
==========================

Both these sort cards are fetching me the same results. How??

Thanks,
Deepesh

Frank Yaeger · Posted: Fri Sep 03, 2004 11:06 am Post subject:

The second method is the correct way.

The first method will not always work. However, if the signs in all of the PD fields are the same (e.g. it's always C), it will appear to work, e.g.

As an example consider the following input (in hex):

1C12345C12345C
2C10000C12345C
2C10001C00005C
0C12345C12345C

Since C is the same in all of the PD values, it has no effect on the result.

But if you had:

1D12345C12345C
2C10000C12345C
2C10001D00005C
0C12345C12345C

The C sign for plus and D sign for minus would be treated correctly as the sign for each individual PD field with the second method, but would not be recognize as the sign the first method.
_________________
Frank Yaeger - DFSORT Development Team (IBM)
Specialties: JOINKEYS, FINDREP, WHEN=GROUP, ICETOOL, Symbols, Migration
DFSORT is on the Web at:
www.ibm.com/storage/dfsort

Cogito-Ergo-Sum · Posted: Fri Sep 03, 2004 11:28 am Post subject:

But, Frank, why is 1,7,PD not treated as 'invalid' PD field in this particular example? A SUM FIELDS on this field does result in S0C7.
_________________
ALL opinions are welcome.

Debugging tip:
When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
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Frank Yaeger · Posted: Fri Sep 03, 2004 12:08 pm Post subject:

Cogito,

DFSORT's SUM processing uses instructions which result in an 0C7 for an invalid PD value.

DFSORT's SORT processing does not use any instructions which result in an 0C7 for an invalid PD value. The invalid sign or digit is just treated as bits.
_________________
Frank Yaeger - DFSORT Development Team (IBM)
Specialties: JOINKEYS, FINDREP, WHEN=GROUP, ICETOOL, Symbols, Migration
DFSORT is on the Web at:
www.ibm.com/storage/dfsort