Suggested solution for proper port of dcopy.f to ulmBLAS.

Bugfix/Optimization  in ddot.c.

Author: michael-lehn

level1/dcopy.c

@@ -1,8 +1,61 @@
 void
-dcopy_(const int    *n,
+dcopy_(const int    *_n,
        const double *x,
-       const int    *incX,
+       const int    *_incX,
        double       *y,
-       const int    *incY)
+       const int    *_incY)
 {
+//
+//  Dereference scalar parameters
+//
+    int n    = *_n;
+    int incX = *_incX;
+    int incY = *_incY;
+
+//
+//  Local scalars
+//
+    int    i, m;
+//
+//  Quick return if possible
+//
+    if (n==0) {
+        return;
+    }
+    if (incX==1 && incY==1) {
+//
+//      Code for both increments equal to 1
+//
+        m = n % 7;
+        if (m!=0) {
+            for (i=0; i<m; ++i) {
+                y[i] = x[i];
+            }
+            if (n<7) {
+                return;
+            }
+        }
+        for (i=m; i<n; i+=7) {
+            y[i  ] = x[i  ];
+            y[i+1] = x[i+1];
+            y[i+2] = x[i+2];
+            y[i+3] = x[i+3];
+            y[i+4] = x[i+4];
+            y[i+5] = x[i+5];
+            y[i+6] = x[i+6];
+        }
+    } else {
+//
+//      Code for unequal increments or equal increments not equal to 1
+//
+        if (incX<0) {
+            x -= incX*(n-1);
+        }
+        if (incY<0) {
+            y -= incY*(n-1);
+        }
+        for (i=0; i<n; ++i, x+=incX, y+=incY) {
+            (*y) = (*x);
+        }
+    }
 }

level1/ddot.c

@@ -30,11 +30,13 @@ ddot_(const int     *_n,
 //      Code for both increments equal to 1
 //
         m = n % 5;
-        for (i=0; i<m; ++i) {
-            result += x[i] * y[i];
-        }
-        if (n<5) {
-            return result;
+        if (m!=0) {
+            for (i=0; i<m; ++i) {
+                result += x[i] * y[i];
+            }
+            if (n<5) {
+                return result;
+            }
         }
         for (i=m; i<n; i+=5) {
             result += x[i  ] * y[i  ] ;