PRINT

NOGEN

TITLE

'EX3A - EXERCISE IN ADDRESSING'

EX3A

CSECT

USING

*,R15

INITIAL BASE REGISTER

BEGIN

B

START

DC

AL1(8),CL8'EX3A'

PROGRAM NAME FOR DEBUGGING

SAVEAREA

DS

0F

MY SAVE AREA

DC

AL4(*-*)

PRESAVE

DC

AL4(*-*)

ADDR OF PREVIOUS SAVE AREA

NEXTSAVE

DC

AL4(*-*)

ADDR OF NEXT SAVE AREA

SREG14

DC

AL4(*-*)

GENERAL

SREG15

DC

AL4(*-*)

- - - ->PURPOSE

SREG0

DC

13AL4(*-*)

- - - - - - - ->REGISTER SAVE

SAVEEND

DS

0H

END OF MY SAVE AREA

SPACE

1

START

EQU

*

DROP

R15

DUMP INITIAL BASE REGISTER

STM

R14,R12,12(R13)

SAVE THE REGISTERS ON ENTRY.

LR

R12,R15

SET UP MY

USING

BEGIN,R12

- - - ->BASE REGISTER

ST

R13,PRESAVE

PERFORM SAVE

LA

R15,SAVEAREA

- - - ->AREA

ST

R15,8(R13)

- - - - - - - ->CHAINING

LR

R13,R15

R13 = ADDR OF MY SAVE AREA.

OPEN

(INDCB,INPUT,OUTDCB,OUTPUT)

EJECT

*

*

PREPARE TO BUILD A LIST OF NAMES IN OUTAREA.

*

LA

R4,NAMETAB

R4 = START OF ARRAY.

READREC

GET

INDCB,INAREA

READ A RECORD

*

*

RETRIEVE THE NAMES AND SORT THEM!

*

CLC

=CL4'****',INAREA

IS IT LAST INPUT RECORD?

BE

READDONE

YEP - STOP READING.

MVC

0(8,R4),INAREA

NO - SLOT NAME IN ARRAY,

LA

R4,8(,R4)

POINT TO NEXT ARRAY SLOT,

B

READREC

AND REPEAT TILL EXHAUSTED.

READDONE

LA

R4,NAMETAB

R4 = START OF ARRAY.

LA

R3,NAMETAB+8

R3 = START OF ARRAY + 1.

CLI

FLAG,SORTED

ARE NAMES IN ORDER?

BE

INFORM

YEP - GO TELL ABOUT IT.

MVI

FLAG,SORTED

NO - INDICATE IT IS.

SORT1

CLI

0(R4),X'FF'

END OF ARRAY?

BE

READDONE

YEP - CHECK ALL DONE,

CLC

0(8,R4),0(R3)

NO - IS FIRST > SECOND?

BH

SWAP

YEP - SWAP THEM

SORT2

LA

R4,8(,R4)

NO - MOVE TO

LA

R3,8(,R3)

- - - ->NEXT

B

SORT1

- - - - - - - ->PAIR.

SWAP

MVC

TEMP,0(R4)

SAVE FIRST NAME, THEN

MVC

0(8,R4),0(R3)

MOVE SECOND NAME FORWARD,

MVC

0(8,R3),TEMP

RETURN FIRST NAME TO ARRAY.

MVI

FLAG,UNSORTED

INDICATE NOT SORTED.

B

SORT2

GO GET NEXT PAIR.

SPACE

1

INFORM

MVC

OUTAREA+1(80),NAMETAB

PUT

OUTDCB,OUTAREA

OUTPUT THE TABLE.

SPACE

3

EXIT

CLOSE

(INDCB,,OUTDCB)

CLOSE BOTH FILES

SR

R15,R15

FORCE COND CODE ZERO

L

R13,PRESAVE

R13 = PREVIOUS SAVE AREA ADDR.

L

R14,12(R13)

RESTORE REGISTERS

LM

R0,R12,20(R13)

EXCEPT REGISTER 15

BR

R14

RETURN TO CALLER (OS/390)

EJECT

LTORG

SPACE

1

TEMP

DS

CL8

SWITCH NAME AREA.

SPACE

1

INDCB

DCB

MACRF=GM ,EODAD=READDONE ,DDNAME=INDD,LRECL=80,

*

DSORG=PS

INAREA

DS

CL80

SPACE

1

OUTDCB

DCB

MACRF=PM, RECFM=F, LRECL=133,DDNAME=OUTDD,DSORG=PS

OUTAREA

DC

CL133' '

SPACE

1

NAMETAB

DC

8X'FF'

FIRST ENTRY - HIGH VALUES

DC

8XL10'FFFFFFFFFFFFFFFF' FURTHER 8 ENTRIES.

NAMETABE

DC

XL1'FF'

END OF NAME TABLE.

FLAG

DC

C'N'

INDICATE NOT SORTED

SORTED

EQU

C'Y'

INDICATE SORTED.

UNSORTED

EQU

C'N'

INDICATE NOT SORTED.

R0

EQU

0

R1

EQU

1

R2

EQU

2

R3

EQU

3

R4

EQU

4

R5

EQU

5

R6

EQU

6

R7

EQU

7

R8

EQU

8

R9

EQU

9

R10

EQU

10

R11

EQU

11

R12

EQU

12

R13

EQU

13

R14

EQU

14

R15

EQU

15

END