1 /* e_hypotf.c -- float version of e_hypot.c.
2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3  */
4 
5 /*
6  * ====================================================
7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8  *
9  * Developed at SunPro, a Sun Microsystems, Inc. business.
10  * Permission to use, copy, modify, and distribute this
11  * software is freely granted, provided that this notice
12  * is preserved.
13  * ====================================================
14  */
15 
16 #include <sys/cdefs.h>
17 __FBSDID("$FreeBSD$");
18 
19 #include "math.h"
20 #include "math_private.h"
21 
22 float
__ieee754_hypotf(float x,float y)23 __ieee754_hypotf(float x, float y)
24 {
25 	float a,b,t1,t2,y1,y2,w;
26 	int32_t j,k,ha,hb;
27 
28 	GET_FLOAT_WORD(ha,x);
29 	ha &= 0x7fffffff;
30 	GET_FLOAT_WORD(hb,y);
31 	hb &= 0x7fffffff;
32 	if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;}
33 	a = fabsf(a);
34 	b = fabsf(b);
35 	if((ha-hb)>0xf000000) {return a+b;} /* x/y > 2**30 */
36 	k=0;
37 	if(ha > 0x58800000) {	/* a>2**50 */
38 	   if(ha >= 0x7f800000) {	/* Inf or NaN */
39 	       /* Use original arg order iff result is NaN; quieten sNaNs. */
40 	       w = fabsf(x+0.0F)-fabsf(y+0.0F);
41 	       if(ha == 0x7f800000) w = a;
42 	       if(hb == 0x7f800000) w = b;
43 	       return w;
44 	   }
45 	   /* scale a and b by 2**-68 */
46 	   ha -= 0x22000000; hb -= 0x22000000;	k += 68;
47 	   SET_FLOAT_WORD(a,ha);
48 	   SET_FLOAT_WORD(b,hb);
49 	}
50 	if(hb < 0x26800000) {	/* b < 2**-50 */
51 	    if(hb <= 0x007fffff) {	/* subnormal b or 0 */
52 	        if(hb==0) return a;
53 		SET_FLOAT_WORD(t1,0x7e800000);	/* t1=2^126 */
54 		b *= t1;
55 		a *= t1;
56 		k -= 126;
57 	    } else {		/* scale a and b by 2^68 */
58 	        ha += 0x22000000; 	/* a *= 2^68 */
59 		hb += 0x22000000;	/* b *= 2^68 */
60 		k -= 68;
61 		SET_FLOAT_WORD(a,ha);
62 		SET_FLOAT_WORD(b,hb);
63 	    }
64 	}
65     /* medium size a and b */
66 	w = a-b;
67 	if (w>b) {
68 	    SET_FLOAT_WORD(t1,ha&0xfffff000);
69 	    t2 = a-t1;
70 	    w  = __ieee754_sqrtf(t1*t1-(b*(-b)-t2*(a+t1)));
71 	} else {
72 	    a  = a+a;
73 	    SET_FLOAT_WORD(y1,hb&0xfffff000);
74 	    y2 = b - y1;
75 	    SET_FLOAT_WORD(t1,(ha+0x00800000)&0xfffff000);
76 	    t2 = a - t1;
77 	    w  = __ieee754_sqrtf(t1*y1-(w*(-w)-(t1*y2+t2*b)));
78 	}
79 	if(k!=0) {
80 	    SET_FLOAT_WORD(t1,0x3f800000+(k<<23));
81 	    return t1*w;
82 	} else return w;
83 }
84