if(hx==0x3f800000) return atanf(y);
if(hx==0x3f800000) return __atanf(y);
	float __ieee754_atan2f(float y, float x)#else	float __ieee754_atan2f(y,x)	float  y,x;#endif{  	float z;	int32_t k,m,hx,hy,ix,iy;	GET_FLOAT_WORD(hx,x);	ix = hx&0x7fffffff;	GET_FLOAT_WORD(hy,y);	iy = hy&0x7fffffff;	if((ix>0x7f800000)||	   (iy>0x7f800000))	/* x or y is NaN */	   return x+y;	if(hx==0x3f800000) return atanf(y);   /* x=1.0 */	m = ((hy>>31)&1)|((hx>>30)&2);	/* 2*sign(x)+sign(y) */    /* when y = 0 */	if(iy==0) {	    switch(m) {		case 0: 		case 1: return y; 	/* atan(+-0,+anything)=+-0 */		case 2: return  pi+tiny;/* atan(+0,-anything) = pi */		case 3: return -pi-tiny;/* atan(-0,-anything) =-pi */	    }	}    /* when x = 0 */	if(ix==0) return (hy<0)?  -pi_o_2-tiny: pi_o_2+tiny;	        /* when x is INF */	if(ix==0x7f800000) {	    if(iy==0x7f800000) {		switch(m) {		    case 0: return  pi_o_4+tiny;/* atan(+INF,+INF) */		    case 1: return -pi_o_4-tiny;/* atan(-INF,+INF) */		    case 2: return  (float)3.0*pi_o_4+tiny;/*atan(+INF,-INF)*/		    case 3: return (float)-3.0*pi_o_4-tiny;/*atan(-INF,-INF)*/		}	    } else {		switch(m) {		    case 0: return  zero  ;	/* atan(+...,+INF) */		    case 1: return -zero  ;	/* atan(-...,+INF) */		    case 2: return  pi+tiny  ;	/* atan(+...,-INF) */		    case 3: return -pi-tiny  ;	/* atan(-...,-INF) */		}	    }	}    /* when y is INF */	if(iy==0x7f800000) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;    /* compute y/x */	k = (iy-ix)>>23;	if(k > 60) z=pi_o_2+(float)0.5*pi_lo; 	/* |y/x| >  2**60 */	else if(hx<0&&k<-60) z=0.0; 	/* |y|/x < -2**60 */	else z=atanf(fabsf(y/x));	/* safe to do y/x */	switch (m) {	    case 0: return       z  ;	/* atan(+,+) */	    case 1: {	    	      u_int32_t zh;		      GET_FLOAT_WORD(zh,z);		      SET_FLOAT_WORD(z,zh ^ 0x80000000);		    }		    return       z  ;	/* atan(-,+) */	    case 2: return  pi-(z-pi_lo);/* atan(+,-) */	    default: /* case 3 */	    	    return  (z-pi_lo)-pi;/* atan(-,-) */	}}