Annotation of rpl/lapack/blas/dcopy.f, revision 1.7
1.1 bertrand 1: SUBROUTINE DCOPY(N,DX,INCX,DY,INCY)
2: * .. Scalar Arguments ..
3: INTEGER INCX,INCY,N
4: * ..
5: * .. Array Arguments ..
6: DOUBLE PRECISION DX(*),DY(*)
7: * ..
8: *
9: * Purpose
10: * =======
11: *
12: * DCOPY copies a vector, x, to a vector, y.
13: * uses unrolled loops for increments equal to one.
14: *
15: * Further Details
16: * ===============
17: *
18: * jack dongarra, linpack, 3/11/78.
19: * modified 12/3/93, array(1) declarations changed to array(*)
20: *
21: * =====================================================================
22: *
23: * .. Local Scalars ..
24: INTEGER I,IX,IY,M,MP1
25: * ..
26: * .. Intrinsic Functions ..
27: INTRINSIC MOD
28: * ..
29: IF (N.LE.0) RETURN
1.7 ! bertrand 30: IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
1.1 bertrand 31: *
1.7 ! bertrand 32: * code for both increments equal to 1
1.1 bertrand 33: *
34: *
1.7 ! bertrand 35: * clean-up loop
1.1 bertrand 36: *
1.7 ! bertrand 37: M = MOD(N,7)
! 38: IF (M.NE.0) THEN
! 39: DO I = 1,M
! 40: DY(I) = DX(I)
! 41: END DO
! 42: IF (N.LT.7) RETURN
! 43: END IF
! 44: MP1 = M + 1
! 45: DO I = MP1,N,7
! 46: DY(I) = DX(I)
! 47: DY(I+1) = DX(I+1)
! 48: DY(I+2) = DX(I+2)
! 49: DY(I+3) = DX(I+3)
! 50: DY(I+4) = DX(I+4)
! 51: DY(I+5) = DX(I+5)
! 52: DY(I+6) = DX(I+6)
! 53: END DO
! 54: ELSE
1.1 bertrand 55: *
1.7 ! bertrand 56: * code for unequal increments or equal increments
! 57: * not equal to 1
1.1 bertrand 58: *
1.7 ! bertrand 59: IX = 1
! 60: IY = 1
! 61: IF (INCX.LT.0) IX = (-N+1)*INCX + 1
! 62: IF (INCY.LT.0) IY = (-N+1)*INCY + 1
! 63: DO I = 1,N
! 64: DY(IY) = DX(IX)
! 65: IX = IX + INCX
! 66: IY = IY + INCY
! 67: END DO
! 68: END IF
1.1 bertrand 69: RETURN
70: END
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