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      SUBROUTINE SROTM(N,SX,INCX,SY,INCY,SPARAM)
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*     .. Scalar Arguments ..
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      INTEGER INCX,INCY,N
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*     ..
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*     .. Array Arguments ..
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      REAL SPARAM(5),SX(1),SY(1)
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*     ..
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*
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*  Purpose
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*  =======
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*
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*     APPLY THE MODIFIED GIVENS TRANSFORMATION, H, TO THE 2 BY N MATRIX
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*
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*     (SX**T) , WHERE **T INDICATES TRANSPOSE. THE ELEMENTS OF SX ARE IN
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*     (DX**T)
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*
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*     SX(LX+I*INCX), I = 0 TO N-1, WHERE LX = 1 IF INCX .GE. 0, ELSE
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*     LX = (-INCX)*N, AND SIMILARLY FOR SY USING USING LY AND INCY.
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*     WITH SPARAM(1)=SFLAG, H HAS ONE OF THE FOLLOWING FORMS..
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*
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*     SFLAG=-1.E0     SFLAG=0.E0        SFLAG=1.E0     SFLAG=-2.E0
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*
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*       (SH11  SH12)    (1.E0  SH12)    (SH11  1.E0)    (1.E0  0.E0)
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*     H=(          )    (          )    (          )    (          )
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*       (SH21  SH22),   (SH21  1.E0),   (-1.E0 SH22),   (0.E0  1.E0).
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*     SEE  SROTMG FOR A DESCRIPTION OF DATA STORAGE IN SPARAM.
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*
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*
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*  Arguments
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*  =========
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*
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*  N      (input) INTEGER
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*         number of elements in input vector(s)
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*
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*  SX     (input/output) REAL array, dimension N
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*         double precision vector with 5 elements
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*
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*  INCX   (input) INTEGER
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*         storage spacing between elements of SX
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*
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*  SY     (input/output) REAL array, dimension N
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*         double precision vector with N elements
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*
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*  INCY   (input) INTEGER
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*         storage spacing between elements of SY
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*
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*  SPARAM (input/output)  REAL array, dimension 5
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*     SPARAM(1)=SFLAG
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*     SPARAM(2)=SH11
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*     SPARAM(3)=SH21
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*     SPARAM(4)=SH12
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*     SPARAM(5)=SH22
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*
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*  =====================================================================
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*
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*     .. Local Scalars ..
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      REAL SFLAG,SH11,SH12,SH21,SH22,TWO,W,Z,ZERO
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      INTEGER I,KX,KY,NSTEPS
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*     ..
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*     .. Data statements ..
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      DATA ZERO,TWO/0.E0,2.E0/
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*     ..
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*
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      SFLAG = SPARAM(1)
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      IF (N.LE.0 .OR. (SFLAG+TWO.EQ.ZERO)) GO TO 140
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      IF (.NOT. (INCX.EQ.INCY.AND.INCX.GT.0)) GO TO 70
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*
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      NSTEPS = N*INCX
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      IF (SFLAG) 50,10,30
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   10 CONTINUE
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      SH12 = SPARAM(4)
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      SH21 = SPARAM(3)
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      DO 20 I = 1,NSTEPS,INCX
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          W = SX(I)
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          Z = SY(I)
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          SX(I) = W + Z*SH12
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          SY(I) = W*SH21 + Z
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   20 CONTINUE
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      GO TO 140
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   30 CONTINUE
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      SH11 = SPARAM(2)
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      SH22 = SPARAM(5)
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      DO 40 I = 1,NSTEPS,INCX
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          W = SX(I)
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          Z = SY(I)
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          SX(I) = W*SH11 + Z
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          SY(I) = -W + SH22*Z
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   40 CONTINUE
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      GO TO 140
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   50 CONTINUE
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      SH11 = SPARAM(2)
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      SH12 = SPARAM(4)
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      SH21 = SPARAM(3)
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      SH22 = SPARAM(5)
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      DO 60 I = 1,NSTEPS,INCX
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          W = SX(I)
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          Z = SY(I)
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          SX(I) = W*SH11 + Z*SH12
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          SY(I) = W*SH21 + Z*SH22
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   60 CONTINUE
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      GO TO 140
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   70 CONTINUE
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      KX = 1
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      KY = 1
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      IF (INCX.LT.0) KX = 1 + (1-N)*INCX
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      IF (INCY.LT.0) KY = 1 + (1-N)*INCY
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*
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      IF (SFLAG) 120,80,100
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   80 CONTINUE
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      SH12 = SPARAM(4)
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      SH21 = SPARAM(3)
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      DO 90 I = 1,N
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          W = SX(KX)
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          Z = SY(KY)
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          SX(KX) = W + Z*SH12
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          SY(KY) = W*SH21 + Z
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          KX = KX + INCX
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          KY = KY + INCY
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   90 CONTINUE
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      GO TO 140
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  100 CONTINUE
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      SH11 = SPARAM(2)
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      SH22 = SPARAM(5)
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      DO 110 I = 1,N
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          W = SX(KX)
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          Z = SY(KY)
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          SX(KX) = W*SH11 + Z
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          SY(KY) = -W + SH22*Z
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          KX = KX + INCX
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          KY = KY + INCY
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  110 CONTINUE
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      GO TO 140
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  120 CONTINUE
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      SH11 = SPARAM(2)
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      SH12 = SPARAM(4)
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      SH21 = SPARAM(3)
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      SH22 = SPARAM(5)
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      DO 130 I = 1,N
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          W = SX(KX)
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          Z = SY(KY)
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          SX(KX) = W*SH11 + Z*SH12
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          SY(KY) = W*SH21 + Z*SH22
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          KX = KX + INCX
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          KY = KY + INCY
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  130 CONTINUE
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  140 CONTINUE
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      RETURN
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      END