1C Derived from lapack
2        PROGRAM test
3        DOUBLE PRECISION DA
4        INTEGER I, N
5        DOUBLE PRECISION DX(9),DY(9)
6
7        EXTERNAL DAXPY
8        N=5
9        DA=1.0
10        DATA DX/-2, -1, -3, -4, 1, 2, 10, 15, 14/
11        DATA DY/0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0/
12        CALL DAXPY (N,DA,DX,DY)
13        DO 10 I = 1, N
14          if (DX(I).ne.DY(I)) STOP 1
1510      CONTINUE
16        STOP
17        END
18
19      SUBROUTINE DAXPY(N,DA,DX,DY)
20      DOUBLE PRECISION DA
21      INTEGER N
22      DOUBLE PRECISION DX(*),DY(*)
23      INTEGER I,IX,IY,M,MP1
24      INTRINSIC MOD
25      IF (N.LE.0) RETURN
26   20 M = MOD(N,4)
27      IF (M.EQ.0) GO TO 40
28      DO 30 I = 1,M
29          DY(I) = DY(I) + DA*DX(I)
30   30 CONTINUE
31      IF (N.LT.4) RETURN
32   40 MP1 = M + 1
33      DO 50 I = MP1,N,4
34          DY(I) = DY(I) + DA*DX(I)
35          DY(I+1) = DY(I+1) + DA*DX(I+1)
36          DY(I+2) = DY(I+2) + DA*DX(I+2)
37          DY(I+3) = DY(I+3) + DA*DX(I+3)
38   50 CONTINUE
39      RETURN
40      END
41