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Why cann't access DCB when RMODE 31.

 
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sandeep chopra

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PostPosted: Wed Nov 03, 2010 8:11 pm    Post subject: Why cann't access DCB when RMODE 31.
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We can access DCB when following combinations of RMODE and AMODE.
AMODE 24 and RMODE 24
AMODE 31 and RMODE 24

But we cann't access DCB when we give AMODE 31 and RMODE ANY.
I know in this case we need to take storage below the line through GETMAIN and we have to move our DCB in that storage. Initially this was the limitation for AMODE 31 also but which was resolved by the IBM.
But after searching in google i did not find a good answer why we can not access DCB when RMODE ANY or RMODE 31?
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dick scherrer

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PostPosted: Wed Nov 03, 2010 8:14 pm    Post subject:
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Hello,

It may help if you post the code for the problem dcb.
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sandeep chopra

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PostPosted: Wed Nov 03, 2010 8:22 pm    Post subject: Reply to: Why cann't access DCB when RMODE 31.
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Hi Dick,

Thanks for your comments. I think no need to post code.It's a general concept in assembler which i want to clear. Whenever we try to access DCB in any assembler program having AMODE 31 and RMODE 31, we get S0C4.
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Robert Sample

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PostPosted: Wed Nov 03, 2010 8:30 pm    Post subject:
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Figure 83 in the DF/SMS Using Datasets manual has reentrant code opening a DCB with AMODE 31 and RMODE ANY -- so it can be done, and your statement
Quote:
But we cann't access DCB when we give AMODE 31 and RMODE ANY.
has something to do with your site and its standards -- not the Assembler.
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Bill O'Boyle

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PostPosted: Wed Nov 03, 2010 8:31 pm    Post subject: Reply to: Why cann't access DCB when RMODE 31.
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You can assemble the program as AMODE 31, RMODE ANY, however, you'd have to obtain 24-Bit dynamic storage (GETMAIN, STORAGE OBTAIN) for the DCB.

The JFCB's address is an AL3 (max address X'007FFFFF') so, this is why 31-Bit addressing will cause a S0C4.

You may want to review DCBE. icon_wink.gif

Bill
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enrico-sorichetti

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PostPosted: Wed Nov 03, 2010 8:36 pm    Post subject: Reply to: Why cann't access DCB when RMODE 31.
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Quote:
But after searching in google i did not find a good answer why we can not access DCB when RMODE ANY or RMODE 31?

because IBM says so. that' s all

DCB must still reside below the line ( 24 bits )
for 31 bit I/O a dcbe macro must be used

http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DGT2D470/CCONTENTS?SHELF=DGT2BK81&DN=SC26-7410-08&DT=20080602122917
and
http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DGT2D551/CCONTENTS?SHELF=DGT2BK81&DN=SC26-7408-07&DT=20090122165044

will tell all You might need to know

a quick and dirty google search with "dcb 31bits" returned some interesting links
http://www.tachyonsoft.com/s8158.pdf
http://www.marcsweb.com/mnweb_370dcb31.shtml
and a few more
to You the pleasure of finding out
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sandeep chopra

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PostPosted: Wed Nov 03, 2010 8:38 pm    Post subject: Reply to: Why cann't access DCB when RMODE 31.
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Thanks for reply Bill.
Yes we take dynamic storage below the line to access DCB for this case. But how can this below the line dynamic storage is accessed but not of DCB directly without moving DCb in dynamic storage.
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UmeySan

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PostPosted: Thu Nov 04, 2010 2:31 pm    Post subject:
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Morning Sir !

As told before, use DCBE.

Programm-Definitions:

Filename = S3MSGS

S3MSGS_DCB DCB
DDNAME=S3MSG,DSORG=PS,MACRF=PM,DCBE=S3MSGS_DCBE

S3MSGS_DCBE DCBE RMODE31=BUFF


Xample-Coding:

USING IHADCB,R4
L R4,=A(S3MSGS_DCB)

IF DCBOFLGS,Z,DCBOFOPN,TM
THEN C='Dataset is not open'
OPEN ((R4),OUTPUT)
EIF
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PeterHolland

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PostPosted: Thu Nov 04, 2010 4:55 pm    Post subject:
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S3MSGS_DCB
S3MSGS_DCBE

Always thought a label has a max of 8 characters.
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Robert Sample

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PostPosted: Thu Nov 04, 2010 5:04 pm    Post subject:
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Peter, Assembler is slowly catching up ... labels can be 31 characters now (IIRC).
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PeterHolland

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PostPosted: Thu Nov 04, 2010 5:19 pm    Post subject:
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Robert Sample wrote:
Peter, Assembler is slowly catching up ... labels can be 31 characters now (IIRC).


Robert,

if thats true, then it is me being stuck in the dark ages. icon_sad.gif

And :

pics, movies or it didnt happen. icon_rolleyes.gif
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Robert Sample

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PostPosted: Thu Nov 04, 2010 5:45 pm    Post subject:
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From the HLASM General Information manual:
Quote:
3.5.7 Symbol Length


High Level Assembler supports three types of symbols:

Ordinary symbols
The format of an ordinary symbol consists of an alphabetic character, followed by a maximum of 62 alphanumeric characters.

Variable symbols
The format of a variable symbol consists of an ampersand (&) followed by an alphabetic character, followed by a maximum of 61 alphanumeric characters.

Sequence symbols
The format of a sequence symbol consists of a period (.) followed by an alphabetic character, followed by a maximum of 61 alphanumeric characters.

External symbols are ordinary symbols used in the name field of START, CSECT, RSECT, COM, DXD, and ALIAS statements, and in the operand field of ENTRY, EXTRN, WXTRN, and ALIAS statements. Symbols used in V-type and Q-type address constants are restricted to 8 characters. You can specify an alias string of up to 64 characters to represent an external symbol.
I was wrong -- 63 is the limit.
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PeterHolland

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PostPosted: Thu Nov 04, 2010 5:56 pm    Post subject:
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Robert,

thanks a lot.
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Bill O'Boyle

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PostPosted: Thu Nov 04, 2010 6:04 pm    Post subject: Re: Why cann't access DCB when RMODE 31.
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PeterHolland wrote:
S3MSGS_DCB
S3MSGS_DCBE

Always thought a label has a max of 8 characters.

Peter,

I have a tough time defining labels greater than eight positions (almost have to force myself), but even IBM DSECTS, Macros, etc, have them, so I go with the flow.

No longer are positions, 10 and 16 enforced either as HLASM has taken on a "Free Flow" format.

HLASM has also incorporated a Macro-Option, which allows (for example), an IF/THE/ELSE construct, cloaking Assembler as some sort of low-level HLL. icon_wink.gif

UmeySan demonstrated this in his above post.

It takes some time to get used to these nuances....

Bill
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PeterHolland

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PostPosted: Thu Nov 04, 2010 6:08 pm    Post subject:
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Bill,

thanks.

All this new stuff makes it terrible difficult for an old hand like me. I think
all the wizzkids on this forum can handle all those novelties better than me. icon_redface.gif
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UmeySan

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PostPosted: Thu Nov 04, 2010 10:05 pm    Post subject:
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Good evening, ladies!

If-constructs and other macros like this had been primordial develloped by IBM. I first came in contact with this in 1980.

Now some shops maintain these macros broaden the range.

But the origin was startet by IBM.
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PeterHolland

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PostPosted: Thu Nov 04, 2010 10:10 pm    Post subject:
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Quote:

Good evening, ladies!


Try to find some IT work where guys are not ladies. icon_rolleyes.gif
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Akatsukami

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PostPosted: Thu Nov 04, 2010 10:25 pm    Post subject:
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PeterHolland wrote:
Quote:

Good evening, ladies!


Try to find some IT work where guys are not ladies. icon_rolleyes.gif

The hard part is finding work where the ladies are not guys icon_wink.gif
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dbzTHEdinosauer

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PostPosted: Thu Nov 04, 2010 10:57 pm    Post subject:
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i personally like aggressive women.
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UmeySan

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PostPosted: Fri Nov 05, 2010 4:09 pm    Post subject:
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Morning gentlemen !

First: @All

"Morning ladies" is a comon phrase within the military jargon.

Second: @Peter

Wizzkids !? -> If you are older than 55, older then me, and an higher ranking officer, then ok, it's on me to clean your shoes and to serve you a drink, otherwise ...

Third: @Dick

I really aggree!!! Just reminds me of this fantastic little busty blond saucy fox, having a fine time on a controller unit during nightshift. But as you already know about me, all blonds have gone, just the good old red wine is still here with me, sitting in my private litte dark and binary universe, thinkink gloomy thoughts and remembering all these good old days. :-))

@ All again:

I won't lett you die a wretched death. There are a lot of new fantastic
enhancements in the Assembler-Language. For example the Cobol Search/String/Unstring pendants SRST & MVST.

Plse forgive my churlishness & let god spend us all a lazy long weekend.

And personaly i thank god, for the possibility to spread my wisdoms during my worktime for a customer and get payed for it. I really love my job.

Nice weekend !
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