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 "math.h"
17 #include "math_private.h"
18
19 float
hypotf(float x,float y)20 hypotf(float x, float y)
21 {
22 float a=x,b=y,t1,t2,yy1,y2,w;
23 int32_t j,k,ha,hb;
24
25 GET_FLOAT_WORD(ha,x);
26 ha &= 0x7fffffff;
27 GET_FLOAT_WORD(hb,y);
28 hb &= 0x7fffffff;
29 if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;}
30 SET_FLOAT_WORD(a,ha); /* a <- |a| */
31 SET_FLOAT_WORD(b,hb); /* b <- |b| */
32 if((ha-hb)>0xf000000) {return a+b;} /* x/y > 2**30 */
33 k=0;
34 if(ha > 0x58800000) { /* a>2**50 */
35 if(ha >= 0x7f800000) { /* Inf or NaN */
36 w = a+b; /* for sNaN */
37 if(ha == 0x7f800000) w = a;
38 if(hb == 0x7f800000) w = b;
39 return w;
40 }
41 /* scale a and b by 2**-68 */
42 ha -= 0x22000000; hb -= 0x22000000; k += 68;
43 SET_FLOAT_WORD(a,ha);
44 SET_FLOAT_WORD(b,hb);
45 }
46 if(hb < 0x26800000) { /* b < 2**-50 */
47 if(hb <= 0x007fffff) { /* subnormal b or 0 */
48 if(hb==0) return a;
49 SET_FLOAT_WORD(t1,0x7e800000); /* t1=2^126 */
50 b *= t1;
51 a *= t1;
52 k -= 126;
53 } else { /* scale a and b by 2^68 */
54 ha += 0x22000000; /* a *= 2^68 */
55 hb += 0x22000000; /* b *= 2^68 */
56 k -= 68;
57 SET_FLOAT_WORD(a,ha);
58 SET_FLOAT_WORD(b,hb);
59 }
60 }
61 /* medium size a and b */
62 w = a-b;
63 if (w>b) {
64 SET_FLOAT_WORD(t1,ha&0xfffff000);
65 t2 = a-t1;
66 w = sqrtf(t1*t1-(b*(-b)-t2*(a+t1)));
67 } else {
68 a = a+a;
69 SET_FLOAT_WORD(yy1,hb&0xfffff000);
70 y2 = b - yy1;
71 SET_FLOAT_WORD(t1,ha+0x00800000);
72 t2 = a - t1;
73 w = sqrtf(t1*yy1-(w*(-w)-(t1*y2+t2*b)));
74 }
75 if(k!=0) {
76 SET_FLOAT_WORD(t1,0x3f800000+(k<<23));
77 return t1*w;
78 } else return w;
79 }
80 DEF_STD(hypotf);
81