#include "clapack.h"

/* Subroutine */ int saxpy_(integer *n, real *sa, real *sx, integer *incx, 
	real *sy, integer *incy)
{
    /* System generated locals */
    integer i__1;

    /* Local variables */
    integer i__, m, ix, iy, mp1;

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*     SAXPY constant times a vector plus a vector. */
/*     uses unrolled loop 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 */
    if (*n <= 0) {
	return 0;
    }
    if (*sa == 0.f) {
	return 0;
    }
    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__) {
	sy[iy] += *sa * sx[ix];
	ix += *incx;
	iy += *incy;
/* L10: */
    }
    return 0;

/*        code for both increments equal to 1 */


/*        clean-up loop */

L20:
    m = *n % 4;
    if (m == 0) {
	goto L40;
    }
    i__1 = m;
    for (i__ = 1; i__ <= i__1; ++i__) {
	sy[i__] += *sa * sx[i__];
/* L30: */
    }
    if (*n < 4) {
	return 0;
    }
L40:
    mp1 = m + 1;
    i__1 = *n;
    for (i__ = mp1; i__ <= i__1; i__ += 4) {
	sy[i__] += *sa * sx[i__];
	sy[i__ + 1] += *sa * sx[i__ + 1];
	sy[i__ + 2] += *sa * sx[i__ + 2];
	sy[i__ + 3] += *sa * sx[i__ + 3];
/* L50: */
    }
    return 0;
} /* saxpy_ */
