```01:       DOUBLE PRECISION FUNCTION DASUM(N,DX,INCX)
02: *     .. Scalar Arguments ..
03:       INTEGER INCX,N
04: *     ..
05: *     .. Array Arguments ..
06:       DOUBLE PRECISION DX(*)
07: *     ..
08: *
09: *  Purpose
10: *  =======
11: *
12: *     DASUM takes the sum of the absolute values.
13: *
14: *  Further Details
15: *  ===============
16: *
17: *     jack dongarra, linpack, 3/11/78.
18: *     modified 3/93 to return if incx .le. 0.
19: *     modified 12/3/93, array(1) declarations changed to array(*)
20: *
21: *  =====================================================================
22: *
23: *     .. Local Scalars ..
24:       DOUBLE PRECISION DTEMP
25:       INTEGER I,M,MP1,NINCX
26: *     ..
27: *     .. Intrinsic Functions ..
28:       INTRINSIC DABS,MOD
29: *     ..
30:       DASUM = 0.0d0
31:       DTEMP = 0.0d0
32:       IF (N.LE.0 .OR. INCX.LE.0) RETURN
33:       IF (INCX.EQ.1) GO TO 20
34: *
35: *        code for increment not equal to 1
36: *
37:       NINCX = N*INCX
38:       DO 10 I = 1,NINCX,INCX
39:           DTEMP = DTEMP + DABS(DX(I))
40:    10 CONTINUE
41:       DASUM = DTEMP
42:       RETURN
43: *
44: *        code for increment equal to 1
45: *
46: *
47: *        clean-up loop
48: *
49:    20 M = MOD(N,6)
50:       IF (M.EQ.0) GO TO 40
51:       DO 30 I = 1,M
52:           DTEMP = DTEMP + DABS(DX(I))
53:    30 CONTINUE
54:       IF (N.LT.6) GO TO 60
55:    40 MP1 = M + 1
56:       DO 50 I = MP1,N,6
57:           DTEMP = DTEMP + DABS(DX(I)) + DABS(DX(I+1)) + DABS(DX(I+2)) +
58:      +            DABS(DX(I+3)) + DABS(DX(I+4)) + DABS(DX(I+5))
59:    50 CONTINUE
60:    60 DASUM = DTEMP
61:       RETURN
62:       END
63: ```