--- /dev/null
+#include "clapack.h"
+
+doublereal sdot_(integer *n, real *sx, integer *incx, real *sy, integer *incy)
+{
+ /* System generated locals */
+ integer i__1;
+ real ret_val;
+
+ /* Local variables */
+ integer i__, m, ix, iy, mp1;
+ real stemp;
+
+/* .. Scalar Arguments .. */
+/* .. */
+/* .. Array Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* forms the dot product of two vectors. */
+/* uses unrolled loops for increments equal to one. */
+/* jack dongarra, linpack, 3/11/78. */
+/* modified 12/3/93, array(1) declarations changed to array(*) */
+
+
+/* .. Local Scalars .. */
+/* .. */
+/* .. Intrinsic Functions .. */
+/* .. */
+ /* Parameter adjustments */
+ --sy;
+ --sx;
+
+ /* Function Body */
+ stemp = 0.f;
+ ret_val = 0.f;
+ if (*n <= 0) {
+ return ret_val;
+ }
+ if (*incx == 1 && *incy == 1) {
+ goto L20;
+ }
+
+/* code for unequal increments or equal increments */
+/* not equal to 1 */
+
+ ix = 1;
+ iy = 1;
+ if (*incx < 0) {
+ ix = (-(*n) + 1) * *incx + 1;
+ }
+ if (*incy < 0) {
+ iy = (-(*n) + 1) * *incy + 1;
+ }
+ i__1 = *n;
+ for (i__ = 1; i__ <= i__1; ++i__) {
+ stemp += sx[ix] * sy[iy];
+ ix += *incx;
+ iy += *incy;
+/* L10: */
+ }
+ ret_val = stemp;
+ return ret_val;
+
+/* code for both increments equal to 1 */
+
+
+/* clean-up loop */
+
+L20:
+ m = *n % 5;
+ if (m == 0) {
+ goto L40;
+ }
+ i__1 = m;
+ for (i__ = 1; i__ <= i__1; ++i__) {
+ stemp += sx[i__] * sy[i__];
+/* L30: */
+ }
+ if (*n < 5) {
+ goto L60;
+ }
+L40:
+ mp1 = m + 1;
+ i__1 = *n;
+ for (i__ = mp1; i__ <= i__1; i__ += 5) {
+ stemp = stemp + sx[i__] * sy[i__] + sx[i__ + 1] * sy[i__ + 1] + sx[
+ i__ + 2] * sy[i__ + 2] + sx[i__ + 3] * sy[i__ + 3] + sx[i__ +
+ 4] * sy[i__ + 4];
+/* L50: */
+ }
+L60:
+ ret_val = stemp;
+ return ret_val;
+} /* sdot_ */