SUBROUTINE YAXIS(YMIN,YMAX,DY,PYMIN,PYMAX)
      REAL*4 YMIN,YMAX,DY,PYMIN,PYMAX
      REAL*4    YFAC,YOFF
      INTEGER*2 YTYPE,YMINB,YMAXB
      COMMON/VYDES/YFAC,YOFF,YTYPE,YMINB,YMAXB
      REAL*4    YAFDU,YADDU,YADDB
      INTEGER*2 YAFDB,YAGRID,YATICK
      COMMON/VYADES/YAFDU,YADDU,YADDB,YAFDB,YAGRID,YATICK
      INTEGER*2 PSPP,PBUFL,PCY,PCYSPP,PBY,POFBY
      REAL*4 PBPIY,PBPCY,PBPIX
      COMMON/VPDP/PSPP,PBUFL,PCY,PCYSPP,PBY,POFBY,PBPIY,PBPCY,PBPIX
      IF(PYMIN.LT.0.0)GO TO 1010
      YTYPE=0
      GO TO 1020
1010  YTYPE=1
      PYMIN=-PYMIN
1020  CONTINUE
      YAGRID=0
      YMINB=PYMIN*PBPIY + .5
      YMAXB=PYMAX*PBPIY + .5
      IF(YTYPE.EQ.1)GO TO 2000
      YADDU=DY
      YADDB=(YMAXB-YMINB)*DY/(YMAX-YMIN)
      IF((DY.GE.0.0).AND.(YMIN.GE.0.0))DEL=.999
      IF((DY.GE.0.0).AND.(YMIN.LT.0.0))DEL=-.001
      IF((DY.LT.0.0).AND.(YMIN.GE.0.0))DEL=.001
      IF((DY.LT.0.0).AND.(YMIN.LT.0.0))DEL=-.999
      YAFDU=DY*IFIX(YMIN/DY+DEL)
      YAFDB=YMINB+YADDB*(YAFDU-YMIN)/DY+.5
      YFAC=YADDB/YADDU
      YOFF=-YMIN*YFAC+YMINB
      YATICK=10
      RETURN
2000  CONTINUE
      YADDU=10.0
      YADDB=(YMAXB-YMINB)/ALOG10(YMAX/YMIN)
      I=IFIX(ALOG10(YMIN)+.999)
      YAFDU=10.0**I
      YAFDB=YMINB+YADDB*ALOG10(YAFDU/YMIN)+.5
      YFAC=YADDB
      YOFF=-ALOG10(YMIN)*YFAC + YMINB
      YATICK=9
      RETURN
      END