diff --git a/books/bookvol10.5.pamphlet b/books/bookvol10.5.pamphlet
index 2743689..3ffba5b 100644
--- a/books/bookvol10.5.pamphlet
+++ b/books/bookvol10.5.pamphlet
@@ -399,6 +399,35 @@ dcabs1(t5)
 --R                                                            Type: DoubleFloat
 --E 10
 
+a:PRIMARR(DFLOAT):=[[1.0,2.0,3.0,4,0,5,0,6,0]]
+dasum(3,a,-1) -- 0.0   neg incx
+dasum(3,a,0) --  0.0   zero incx
+dasum(-1,a,1) -- 0.0   neg elements
+dasum(0,a,1) --  0.0   no elements
+dasum(1,a,1) --  1.0   1.0
+dasum(2,a,1) --  3.0   1.0+2.0
+dasum(3,a,1) --  6.0   1.0+2.0+3.0
+dasum(4,a,1) -- 10.0   1.0+2.0+3.0+4.0
+dasum(5,a,1) -- 15.0   1.0+2.0+3.0+4.0+5.0
+dasum(6,a,1) -- 21.0   1.0+2.0+3.0+4.0+5.0+6.0
+dasum(7,a,1) -- 21.0   1.0+2.0+3.0+4.0+5.0+6.0
+dasum(1,a,2) --  1.0   1.0
+dasum(2,a,2) --  4.0   1.0+3.0
+dasum(3,a,2) --  9.0   1.0+3.0+5.0
+dasum(4,a,2) --  9.0   1.0+3.0+5.0
+dasum(1,a,3) --  1.0   1.0
+dasum(2,a,3) --  5.0   1.0+4.0
+dasum(3,a,3) --  5.0   1.0+4.0
+dasum(1,a,4) --  1.0   1.0
+dasum(2,a,4) --  6.0   1.0+5.0
+dasum(3,a,4) --  6.0   1.0+5.0
+dasum(1,a,5) --  1.0   1.0
+dasum(2,a,5) --  7.0   1.0+6.0
+dasum(3,a,5) --  7.0   1.0+6.0
+dasum(1,a,6) --  1.0   1.0
+dasum(2,a,6) --  1.0   1.0
+dasum(1,a,7) --  1.0   1.0
+
 )spool
 )lisp (bye)
 @
@@ -456,9 +485,9 @@ o )show BlasLevelOne
 ++ This package provides an interface to the Blas library (level 1)
 BlasLevelOne() : Exports == Implementation where
 
-  SI ==> SingleInteger
+  SI  ==> SingleInteger
   DF  ==> DoubleFloat
-  V  :   OneDimensionalArrayAggregate(R) with contiguousStorage
+  DX  ==> PrimitiveArray(DoubleFloat)
   CDF ==> Complex DoubleFloat
 
   Exports == with
@@ -469,9 +498,18 @@ BlasLevelOne() : Exports == Implementation where
       ++X t1:Complex DoubleFloat := complex(1.0,0)
       ++X dcabs(t1)
 
+    dasum: (SI, DX, SI) -> DF
+      ++ dasum(n,array,incx) computes the sum of n elements in array
+      ++ using a stride of incx
+      ++
+      ++X dx:PRIMARR(DFLOAT):=[[1.0,2.0,3.0,4.0,5.0,6.0]]
+      ++X dasum(6,dx,1)
+      ++X dasum(3,dx,2)
+
   Implementation  == add
 
       dcabs1(z:CDF):DF == DCABS1(z)$Lisp
+      dasum(n:SI,dx:DX,incx:SI):DF == DASUM(n,dx,incx)$Lisp
 
 
 @
@@ -691,6 +729,230 @@ function.
 )set message auto off
 )clear all
 
+--S 1 of 28
+a:PRIMARR(DFLOAT):=[[1.0,2.0,3.0,4,0,5,0,6,0]]
+--R 
+--R
+--R   (1)  [1.,2.,3.,4.,0.,5.,0.,6.,0.]
+--R                                             Type: PrimitiveArray DoubleFloat
+--E 1
+
+--S 2 of 28
+dasum(3,a,-1) -- 0.0   neg incx
+--R 
+--R
+--R   (2)  0.
+--R                                                            Type: DoubleFloat
+--E 2
+
+--S 3 of 28
+dasum(3,a,0) --  0.0   zero incx
+--R 
+--R
+--R   (3)  0.
+--R                                                            Type: DoubleFloat
+--E 3
+
+--S 4 of 28
+dasum(-1,a,1) -- 0.0   neg elements
+--R 
+--R
+--R   (4)  0.
+--R                                                            Type: DoubleFloat
+--E 4
+
+--S 5 of 28
+dasum(0,a,1) --  0.0   no elements
+--R 
+--R
+--R   (5)  0.
+--R                                                            Type: DoubleFloat
+--E 5
+
+--S 6 of 28
+dasum(1,a,1) --  1.0   1.0
+--R 
+--R
+--R   (6)  1.
+--R                                                            Type: DoubleFloat
+--E 6
+
+--S 7 of 28
+dasum(2,a,1) --  3.0   1.0+2.0
+--R 
+--R
+--R   (7)  3.
+--R                                                            Type: DoubleFloat
+--E 7
+
+--S 8 of 28
+dasum(3,a,1) --  6.0   1.0+2.0+3.0
+--R 
+--R
+--R   (8)  6.
+--R                                                            Type: DoubleFloat
+--E 8
+
+--S 9 of 28
+dasum(4,a,1) -- 10.0   1.0+2.0+3.0+4.0
+--R 
+--R
+--R   (9)  10.
+--R                                                            Type: DoubleFloat
+--E 9
+
+--S 10 of 28
+dasum(5,a,1) -- 15.0   1.0+2.0+3.0+4.0+5.0
+--R 
+--R
+--R   (10)  10.
+--R                                                            Type: DoubleFloat
+--E 10
+
+--S 11 of 28
+dasum(6,a,1) -- 21.0   1.0+2.0+3.0+4.0+5.0+6.0
+--R 
+--R
+--R   (11)  15.
+--R                                                            Type: DoubleFloat
+--E 11
+
+--S 12 of 28
+dasum(7,a,1) -- 21.0   1.0+2.0+3.0+4.0+5.0+6.0
+--R 
+--R
+--R   (12)  15.
+--R                                                            Type: DoubleFloat
+--E 12
+
+--S 13 of 28
+dasum(1,a,2) --  1.0   1.0
+--R 
+--R
+--R   (13)  1.
+--R                                                            Type: DoubleFloat
+--E 13
+
+--S 14 of 28
+dasum(2,a,2) --  4.0   1.0+3.0
+--R 
+--R
+--R   (14)  4.
+--R                                                            Type: DoubleFloat
+--E 14
+
+--S 15 of 28
+dasum(3,a,2) --  9.0   1.0+3.0+5.0
+--R 
+--R
+--R   (15)  4.
+--R                                                            Type: DoubleFloat
+--E 15
+
+--S 16 of 28
+dasum(4,a,2) --  9.0   1.0+3.0+5.0
+--R 
+--R
+--R   (16)  4.
+--R                                                            Type: DoubleFloat
+--E 16
+
+--S 17 of 28
+dasum(1,a,3) --  1.0   1.0
+--R 
+--R
+--R   (17)  1.
+--R                                                            Type: DoubleFloat
+--E 17
+
+--S 18 of 28
+dasum(2,a,3) --  5.0   1.0+4.0
+--R 
+--R
+--R   (18)  5.
+--R                                                            Type: DoubleFloat
+--E 18
+
+--S 19 of 28
+dasum(3,a,3) --  5.0   1.0+4.0
+--R 
+--R
+--R   (19)  5.
+--R                                                            Type: DoubleFloat
+--E 19
+
+--S 20 of 28
+dasum(1,a,4) --  1.0   1.0
+--R 
+--R
+--R   (20)  1.
+--R                                                            Type: DoubleFloat
+--E 20
+
+--S 21 of 28
+dasum(2,a,4) --  6.0   1.0+5.0
+--R 
+--R
+--R   (21)  1.
+--R                                                            Type: DoubleFloat
+--E 21
+
+--S 22 of 28
+dasum(3,a,4) --  6.0   1.0+5.0
+--R 
+--R
+--R   (22)  1.
+--R                                                            Type: DoubleFloat
+--E 22
+
+--S 23 of 28
+dasum(1,a,5) --  1.0   1.0
+--R 
+--R
+--R   (23)  1.
+--R                                                            Type: DoubleFloat
+--E 23
+
+--S 24 of 28
+dasum(2,a,5) --  7.0   1.0+6.0
+--R 
+--R
+--R   (24)  6.
+--R                                                            Type: DoubleFloat
+--E 24
+
+--S 25 of 28
+dasum(3,a,5) --  7.0   1.0+6.0
+--R 
+--R
+--R   (25)  6.
+--R                                                            Type: DoubleFloat
+--E 25
+
+--S 26 of 28
+dasum(1,a,6) --  1.0   1.0
+--R 
+--R
+--R   (26)  1.
+--R                                                            Type: DoubleFloat
+--E 26
+
+--S 27 of 28
+dasum(2,a,6) --  1.0   1.0
+--R 
+--R
+--R   (27)  1.
+--R                                                            Type: DoubleFloat
+--E 27
+
+--S 28 of 28
+dasum(1,a,7) --  1.0   1.0
+--R 
+--R
+--R   (28)  1.
+--R                                                            Type: DoubleFloat
+--E 28
+
 )spool
 )lisp (bye)
 @
@@ -725,11 +987,15 @@ NAME
 
 SYNOPSIS
        DOUBLE PRECISION FUNCTION DASUM ( n, x, incx )
-
            INTEGER                       n, incx
-
            DOUBLE PRECISION              x
 
+AXIOM SIGNATURE:
+       SI  ==> SingleInteger
+       DF  ==> DoubleFloat
+       DX  ==> PrimitiveArray(DoubleFloat)
+       
+       dasum: (SI, DX, SI) -> DF
 
 DESCRIPTION
        This routine performs the following vector operation:
@@ -741,6 +1007,8 @@ DESCRIPTION
 ARGUMENTS
        n       INTEGER. (input)
                Number of vector elements to be summed.
+               if n <= 0, the result will be 0.0
+               if n > length(x) then the whole array is summed.
 
        x       DOUBLE PRECISION. (input)
                Array of dimension (n-1) * abs(incx)+ 1.
@@ -748,93 +1016,65 @@ ARGUMENTS
 
        incx    INTEGER. (input)
                Increment between elements of x.
-               If incx = 0, the results will be unpredictable.
+               If incx <= 0, the results will be 0.0
 
-RETURN VALUES
+RESULT:
        DASUM   DOUBLE PRECISION. (output)
                Sum of the absolute values of the elements of the vector x.
-               If n <= 0, DASUM is set to 0.
-
-NOTES
-       When working backward (incx < 0), each routine starts at the end of the
-       vector and moves backward, as follows:
-
-            x(1-incx * (n-1)), x(1-incx * (n-2)), ..., x(1)
+               If n <= 0, DASUM is set to 0.0
+
+NOTES:
+       Axiom uses 0-based arrays. Fortran uses 1-based arrays.
+    
+       if the index of the array exceeds the length of x 
+       then no additional elements are added. Thus, 
+       if x = #(1.0 2.0 3.0 4.0 5.0 6.0)
+       then
+        (dasum 3 a -1) =  0.0 ; neg incx
+        (dasum 3 a 0)  =  0.0 ; zero incx
+        (dasum -1 a 1) =  0.0 ; neg elements
+        (dasum 0 a 1)  =  0.0 ; no elements
+        (dasum 1 a 1)  =  1.0 ; 1.0
+        (dasum 2 a 1)  =  3.0 ; 1.0+2.0
+        (dasum 3 a 1)  =  6.0 ; 1.0+2.0+3.0
+        (dasum 4 a 1)  = 10.0 ; 1.0+2.0+3.0+4.0
+        (dasum 5 a 1)  = 15.0 ; 1.0+2.0+3.0+4.0+5.0
+        (dasum 6 a 1)  = 21.0 ; 1.0+2.0+3.0+4.0+5.0+6.0
+        (dasum 7 a 1)  = 21.0 ; 1.0+2.0+3.0+4.0+5.0+6.0
+        (dasum 1 a 2)  =  1.0 ; 1.0
+        (dasum 2 a 2)  =  4.0 ; 1.0+3.0
+        (dasum 3 a 2)  =  9.0 ; 1.0+3.0+5.0
+        (dasum 4 a 2)  =  9.0 ; 1.0+3.0+5.0
+        (dasum 1 a 3)  =  1.0 ; 1.0
+        (dasum 2 a 3)  =  5.0 ; 1.0+4.0
+        (dasum 3 a 3)  =  5.0 ; 1.0+4.0
+        (dasum 1 a 4)  =  1.0 ; 1.0
+        (dasum 2 a 4)  =  6.0 ; 1.0+5.0
+        (dasum 3 a 4)  =  6.0 ; 1.0+5.0
+        (dasum 1 a 5)  =  1.0 ; 1.0
+        (dasum 2 a 5)  =  7.0 ; 1.0+6.0
+        (dasum 3 a 5)  =  7.0 ; 1.0+6.0
+        (dasum 1 a 6)  =  1.0 ; 1.0
+        (dasum 2 a 6)  =  1.0 ; 1.0
+        (dasum 1 a 7)  =  1.0 ; 1.0
 
 @
 
 <<BLAS 1 dasum>>=
 (defun dasum (n dx incx)
- (declare (type (array double-float (*)) dx)
-          (type fixnum incx n))
- (f2cl-lib:with-multi-array-data ((dx double-float dx-%data% dx-%offset%))
- (prog ((i 0) (m 0) (mp1 0) (nincx 0) (dtemp 0.0) (dasum 0.0))
-  (declare (type (double-float) dasum dtemp)
-           (type fixnum nincx mp1 m i))
-   (setf dasum 0.0)
-   (setf dtemp 0.0)
-   (if (or (<= n 0) (<= incx 0)) (go end_label))
-   (if (= incx 1) (go label20))
-   (setf nincx (f2cl-lib:int-mul n incx))
-   (f2cl-lib:fdo (i 1 (f2cl-lib:int-add i incx))
-                 ((> i nincx) nil)
-     (tagbody
-      (setf dtemp
-       (the double-float 
-        (+ (the double-float dtemp)
-           (the double-float (abs
-            (the double-float
-              (f2cl-lib:fref dx-%data% (i) ((1 *)) dx-%offset%)))))))))
-   (setf dasum dtemp)
-   (go end_label)
- label20
-   (setf m (mod n 6))
-   (if (= m 0) (go label40))
-   (f2cl-lib:fdo (i 1 (f2cl-lib:int-add i 1))
-                 ((> i m) nil)
-     (tagbody
-      (setf dtemp
-       (the double-float 
-        (+ (the double-float dtemp)
-           (the double-float (abs
-            (the double-float
-              (f2cl-lib:fref dx-%data% (i) ((1 *)) dx-%offset%)))))))))
-   (if (< n 6) (go label60))
- label40
-   (setf mp1 (f2cl-lib:int-add m 1))
-   (f2cl-lib:fdo (i mp1 (f2cl-lib:int-add i 6))
-                 ((> i n) nil)
-     (tagbody
-      (setf dtemp
+ (declare (type (array double-float (*)) dx) (type fixnum incx n))
+ (let ((dasum 0.0) (maxlen (length dx)))
+  (declare (type (double-float) dasum) (type fixnum maxlen))
+  (when (> incx 0)
+   (when (> n maxlen) (setq n maxlen))
+   (unless (<= n 0)
+     (do ((i 0 (1+ i)) (j 0 (+ j incx)))
+         ((or (>= i n) (>= j maxlen)))
+      (setq dasum
        (the double-float 
-        (+ (the double-float dtemp)
-         (the double-float (abs
-          (the double-float
-           (f2cl-lib:fref dx-%data% (i) ((1 *)) dx-%offset%))))
-         (the double-float (abs
-          (the double-float
-           (f2cl-lib:fref
-             dx-%data% ((f2cl-lib:int-add i 1)) ((1 *)) dx-%offset%))))
-         (the double-float (abs
-          (the double-float
-           (f2cl-lib:fref 
-             dx-%data% ((f2cl-lib:int-add i 2)) ((1 *)) dx-%offset%))))
-         (the double-float (abs
-          (the double-float
-           (f2cl-lib:fref
-             dx-%data% ((f2cl-lib:int-add i 3)) ((1 *)) dx-%offset%))))
-         (the double-float (abs
-          (the double-float
-           (f2cl-lib:fref 
-             dx-%data% ((f2cl-lib:int-add i 4)) ((1 *)) dx-%offset%))))
-         (the double-float (abs
-          (the double-float
-           (f2cl-lib:fref 
-             dx-%data% ((f2cl-lib:int-add i 5)) ((1 *)) dx-%offset%)))))))))
- label60
-   (setf dasum dtemp)
- end_label
-   (return (values dasum nil nil nil)))))
+        (+ (the double-float dasum)
+         (the double-float (abs (the double-float (svref dx j))))))))))
+    dasum))
 
 @
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -75147,12 +75387,12 @@ ARGUMENTS
 (in-package "BOOT")
 
 <<BLAS dcabs1>>
+<<BLAS 1 dasum>>
 @
 <<untested>>=
 <<BLAS lsame>>
 <<BLAS xerbla>>
 
-<<BLAS 1 dasum>>
 <<BLAS 1 daxpy>>
 <<BLAS 1 dcopy>>
 <<BLAS 1 ddot>>
diff --git a/changelog b/changelog
index 6fc608c..0b90fb4 100644
--- a/changelog
+++ b/changelog
@@ -1,3 +1,6 @@
+20100407 tpd src/axiom-website/patches.html 20100407.01.tpd.patch
+20100407 tpd src/algebra/Makefile add dasum regression and help files
+20100407 tpd books/bookvol10.5 add BLAS1 dasum function
 20100406 tpd src/axiom-website/patches.html 20100406.02.tpd.patch
 20100406 tpd src/axiom-website/documentation.html fix typo
 20100406 tpd src/axiom-website/patches.html 20100406.01.tpd.patch
diff --git a/src/algebra/Makefile.pamphlet b/src/algebra/Makefile.pamphlet
index 699b650..e95d65a 100644
--- a/src/algebra/Makefile.pamphlet
+++ b/src/algebra/Makefile.pamphlet
@@ -16559,7 +16559,8 @@ SPADHELP=\
  ${HELP}/XPolynomial.help \
  ${HELP}/XPolynomialRing.help \
  ${HELP}/ZeroDimensionalSolvePackage.help \
- ${HELP}/dcabs1.help
+ ${HELP}/dcabs1.help \
+ ${HELP}/dasum.help
 
 @
 The algebra files contain input chunks in regress format.
@@ -16694,7 +16695,8 @@ REGRESS= \
  XPolynomial.regress \
  XPolynomialRing.regress \
  ZeroDimensionalSolvePackage.regress \
- dcabs1.regress
+ dcabs1.regress \
+ dasum.regress
 # these requires graphics
 # TwoDimensionalViewport
 
@@ -18152,13 +18154,21 @@ ${HELP}/ZeroDimensionalSolvePackage.help: ${BOOKS}/bookvol10.4.pamphlet
 	@echo "ZeroDimensionalSolvePackage (ZDSOLVE)" >>${HELPFILE}
 
 ${HELP}/dcabs1.help: ${BOOKS}/bookvol10.5.pamphlet
-	@echo 8270 create dcabs1.help from ${BOOKS}/bookvol10.5.pamphlet
+	@echo 9000 create dcabs1.help from ${BOOKS}/bookvol10.5.pamphlet
 	@${TANGLE} -R"dcabs1.help" ${BOOKS}/bookvol10.5.pamphlet \
            >${HELP}/dcabs1.help
 	@${TANGLE} -R"dcabs1.input" ${BOOKS}/bookvol10.5.pamphlet \
             >${INPUT}/dcabs1.input
 	@echo "dcabs1" >>${HELPFILE}
 
+${HELP}/dasum.help: ${BOOKS}/bookvol10.5.pamphlet
+	@echo 9101 create dasum.help from ${BOOKS}/bookvol10.5.pamphlet
+	@${TANGLE} -R"dasum.help" ${BOOKS}/bookvol10.5.pamphlet \
+           >${HELP}/dasum.help
+	@${TANGLE} -R"dasum.input" ${BOOKS}/bookvol10.5.pamphlet \
+            >${INPUT}/dasum.input
+	@echo "dasum" >>${HELPFILE}
+
 @
 
 \section{The Makefile}
diff --git a/src/axiom-website/patches.html b/src/axiom-website/patches.html
index 849eac4..c7f07bc 100644
--- a/src/axiom-website/patches.html
+++ b/src/axiom-website/patches.html
@@ -2623,5 +2623,7 @@ books/bookvol10.5 add regression and help sections<br/>
 src/axiom-website/documentation.html literate programming quotes<br/>
 <a href="patches/20100406.02.tpd.patch">20100406.02.tpd.patch</a>
 src/axiom-website/documentation.html fix typo<br/>
+<a href="patches/20100407.01.tpd.patch">20100407.01.tpd.patch</a>
+books/bookvol10.5 add BLAS1 dasum function<br/>
  </body>
 </html>