|
View previous topic :: View next topic
|
| Author |
Message |
mjadwani2785
New User
Joined: 28 Apr 2009
Posts: 89
Location: Noida , Dublin
|
|
|
|
Hello All ,
This is the simple code I wrote to teach myself little Assembler .
All the code is doing is copying the data in variable TCH to PS Dataset .
When I am running this program job abends with S0C1 abend .
If any one can help me to point me what mistake I am doing ?
I tried to do little dump analysis of SYSUDUMP I am getting lost when PUT macro executes ( ICM instruction executes within macro ) .
| Code: |
TITLE 'TEST DATASET PROGRAM'
TESTDS CSECT
SAVE (14,12) SAVING THE STATE OF REGISTERS
BASR 12,0 ESTABLISH BASE ADDRESS
USING *,12 ESTABLISH BASE ADDRESS
ST 13,SAV1+4
LA 13,SAV1
*PRACTISING ASSEMBLER MACROS ON DATASET
OPEN (OUTX,(OUTPUT))
PUT OUTX,TCH
CLOSE OUTX
OUTX DCB DDNAME=MYOUT,DSORG=PS,MACRF=(PM),RECFM=FB,LRECL=80, X
BLKSIZE=80
*RETURN CONTROL TO OS
L 13,SAV1+4
RETURN (14,12),RC=0
BR 14
*VARIABLES AND SAVEAREAS
TCH DC CL80'Hello World'
SAV1 DS 18F SAVE AREA
END
|
Please suggest .
Regards,
Manoj Jadwani |
|
| Back to top |
|
 |
Garry Carroll
Senior Member
Joined: 08 May 2006
Posts: 1216
Location: Dublin, Ireland
|
|
|
|
Why have you got the DCB coded within the executable code? A DCB is not executable.
Try moving it to where you have VARIABLES and SAVEAREAS defined.
Garry. |
|
| Back to top |
|
|
mjadwani2785
New User
Joined: 28 Apr 2009
Posts: 89
Location: Noida , Dublin
|
|
|
|
Hi Garry ,
Thanks , It really worked !!
Is it like all the constants and variables used in any assembler program should be group together and coded ?
When you say DCB is not executable ( I can also see that in DUMPS it contains all data constants ) can I find same information in manual where it says where you should code your DCB .
Sorry if I sound silly , its just I am new to Assembler and learning from all the source available on net .
Regards,
Manoj Jadwani |
|
| Back to top |
|
|
Robert Sample
Global Moderator
Joined: 06 Jun 2008
Posts: 8700
Location: Dubuque, Iowa, USA
|
|
|
|
| SHARE has run an Assembler Boot Camp several times during their annual conference. Google assembler boot camp for more information. There are several sessions during the week and they will give you at least a basic understanding of z/OS assembler. |
|
| Back to top |
|
|
steve-myers
Active Member
Joined: 30 Nov 2013
Posts: 917
Location: The Universe
|
|
|
|
| Code: |
2 PUT ADCB,ANAREA
000000 4110 C010 00010 4+ LA 1,ADCB
000004 4100 C010 00010 5+ LA 0,ANAREA
000008 1FFF 6+ SLR 15,15
00000A BFF7 1031 00031 7+ ICM 15,7,49(1)
00000E 05EF 8+ BALR 14,15 |
The DCB is a rather large data area. Part of it is supplied by your program in the DCB macro, the remainder is filled in when you open the DCB.
LA 1,ADCB
LA 0,ANAREA
Those instruction are pretty self explanatory.
SLR 15,15
ICM 15,7,49(1)
BALR 14,15
To fully understand these instructions we must go back to history.
OS/360 was supposed to run in a system with 32K bytes of storage. Now this is hard to comprehend in a day when the desktop workstation I'm using to compose this has 6 gigabytes of storage, but in 1965/1966 32K was a BIG machine. The programmers were fighting for every byte of storage. The OS/360 PUT macro was
L 15,48(,1)
BALR 14,15
The storage byte at offset 48 in the DCB was used for something - I no longer remember what it was used for and it's not important. The 24-bit address of the code that processes a PUT request was (and still is) filled in by OPEN in bytes 49 through 51. In System/36 only the low order 24-bits of register 15 were used for the branch address in the BALR; the high order 8 bits were ignored. In the early 1980s when IBM provided for more than 16 meg of storage the old code would no longer work, so IBM changed it to SLR/ICM/BALR to make sure the higher order byte of register 15 was 0 before it executed the BALR instruction. |
|
| Back to top |
|
|
|
|
  |
All times are GMT + 6 Hours |
|
