*********************************************************************
* Z390 MAINFRAME ASSEMBLER CODING CONTEST PROBLEM #20.
********************************************************************* 
*********************************************************************
P20WR1   ZMFACC CODE,START,NAME='WERNER RAMS',RUNSYS=390
*
*  THE IDEA IS NOT FROM MYSELF, BUT IS PUBLISHED IN
*  THE INTERNET FOR THE RANDOM-FUNCTION OF HIGHER PROGRAMMING LANG.
*  THE FORMULA IS X1 = (397204094*X0) MOD (2 ^ 31 -1)
*  THE FIRST X0 IS THE VALUE OF SEED
*  THE FORMULA THEN GENERATES 2 ^ 31 -1 DIFFERENT PSEUDO RANDOM NUMBERS 
*
*  ON MY PC THE PROGRAM RUNS ABOUT 1 1/2 HOURS (BY 5 MIPS)
*
         MVC    LFDZAHL,SEED 
         SR     R4,R4
         L      R2,=X'7FFFFFFF'
ANF010   EQU   *
         L      R15,LFDZAHL
         M      R14,KONST
         D      R14,=X'7FFFFFFF'
         ST     R14,LFDZAHL 
         C      R14,SEED
         BE     END000  
         AHI    R4,1
         BCT    R2,ANF010 
END000   EQU    * 
         CVD    R14,DW
         MVC    ZUFALL,SCHAB
         ED     ZUFALL,DW+2
         WTO    MF=(E,WTOMSG)
         CVD    R4,DW
         MVC    ZUFALL,SCHAB
         ED     ZUFALL,DW+2
         WTO    MF=(E,WTOMSG)
         ZMFACC CODE,END 
         ZMFACC INPUT,START 
SEED     DC     F'101'     CAN BE ANY NUMBER, BUT NOT ZERO      
KONST    DC     F'397204094' THIS IS FROM THE INTERNET
         ZMFACC INPUT,END
LFDZAHL  DS     F         
BITTAB   DC     X'8040201008040201' 
         ZMFACC OUTPUT,START
         ZMFACC OUTPUT,END
DW       DS     D 
SCHAB    DC     X'4020204B2020204B2020204B202020'
WTOMSG   DC     AL2(WTOEND-WTOMSG,0),C'ZUFALL ='
ZUFALL   DS     CL15
WTOEND   EQU    * 
         LTORG
         END