*
* $Id: rg32.F,v 1.1.1.1 1996/04/01 15:02:55 mclareni Exp $
*
* $Log: rg32.F,v $
* Revision 1.1.1.1  1996/04/01 15:02:55  mclareni
* Mathlib gen
*
*
#include "gen/pilot.h"
#if defined(CERNLIB_VAX)
      OPTIONS/CHECK=NOOVERFLOW
#endif
      FUNCTION RG32(IDUMMY)
#if defined(CERNLIB_CRAY)
CDIR$ INTEGER=64
#endif
C         MACHINE-INDEPENDENT RANDOM NUMBER GENERATOR
C         PRODUCES GAUSSIAN-DISTRIBUTED FLOATING-PT.
C               NUMBERS OF MEAN ZERO AND VARIANCE ONE.
C         IDENTICAL SEQUENCE ON ALL MACHINES OF .GE. 32 BITS.
C              UNIVERSAL VERSION,  F.JAMES, 1985
C              IY     IS THE SEED,
C              CONS   IS 2**-23
C              MASK31 IS 17777777777 OCTAL
      PARAMETER (CONS=1.1920928955078E-07, MASK31=2147483647)
CSELF,IF=-IBM. CERN EDITLIB+SIEMENS COMPILER PROBLEM.
      SAVE IY
CSELF.
      DATA IY/875949887/
C
      JSUM = 0
      DO 50 LOOP= 1, 12
      IY = IY * 69069
C         KEEP ONLY LOWER 31 BITS
      IY = IAND (IY, MASK31)
C         SHIFT RIGHT 8 BITS TO AVOID OVFLO
      JY = IY /256
      JSUM = JSUM + JY
   50 CONTINUE
C         CORRECT FOR TRUNCATION BIAS AND ROUND TO NEAREST
C         EVEN BYTE TO ASSURE EXACT FLOAT
      JSUM = (JSUM+134)/256*256
C
      RG32 = CONS*JSUM - 6.0
      RETURN
C         ENTRY TO INPUT SEED
      ENTRY RG32IN (IDUMMY)
      IY = IDUMMY
      RG32IN = 0.
      RETURN
C         ENTRY TO OUTPUT SEED
      ENTRY RG32OT (IDUMMY)
      IDUMMY = IY
      RG32OT = 0.
      RETURN
      END