#include "f2c.h"

#ifdef KR_headers
#ifdef IEEE_drem
double drem();
#else
double floor();
#endif
double d_mod(x,y) doublereal *x, *y;
#else
#ifdef IEEE_drem
double drem(double, double);
#else
#undef abs
#include "math.h"
#endif
double d_mod(doublereal *x, doublereal *y)
#endif
{
#ifdef IEEE_drem
        double xa, ya, z;
        if ((ya = *y) < 0.)
                ya = -ya;
        z = drem(xa = *x, ya);
        if (xa > 0) {
                if (z < 0)
                        z += ya;
                }
        else if (z > 0)
                z -= ya;
        return z;
#else
        double quotient;
        if( (quotient = *x / *y) >= 0)
                quotient = floor(quotient);
        else
                quotient = -floor(-quotient);
        return(*x - (*y) * quotient );
#endif
}
