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 #ifndef lint 17 static char rcsid[] = "$FreeBSD$"; 18 #endif 19 20 #include "math.h" 21 #include "math_private.h" 22 23 #ifdef __STDC__ 24 float __ieee754_hypotf(float x, float y) 25 #else 26 float __ieee754_hypot(x,y) 27 float x, y; 28 #endif 29 { 30 float a=x,b=y,t1,t2,y1,y2,w; 31 int32_t j,k,ha,hb; 32 33 GET_FLOAT_WORD(ha,x); 34 ha &= 0x7fffffff; 35 GET_FLOAT_WORD(hb,y); 36 hb &= 0x7fffffff; 37 if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;} 38 SET_FLOAT_WORD(a,ha); /* a <- |a| */ 39 SET_FLOAT_WORD(b,hb); /* b <- |b| */ 40 if((ha-hb)>0xf000000) {return a+b;} /* x/y > 2**30 */ 41 k=0; 42 if(ha > 0x58800000) { /* a>2**50 */ 43 if(ha >= 0x7f800000) { /* Inf or NaN */ 44 w = a+b; /* for sNaN */ 45 if(ha == 0x7f800000) w = a; 46 if(hb == 0x7f800000) w = b; 47 return w; 48 } 49 /* scale a and b by 2**-68 */ 50 ha -= 0x22000000; hb -= 0x22000000; k += 68; 51 SET_FLOAT_WORD(a,ha); 52 SET_FLOAT_WORD(b,hb); 53 } 54 if(hb < 0x26800000) { /* b < 2**-50 */ 55 if(hb <= 0x007fffff) { /* subnormal b or 0 */ 56 if(hb==0) return a; 57 SET_FLOAT_WORD(t1,0x7e800000); /* t1=2^126 */ 58 b *= t1; 59 a *= t1; 60 k -= 126; 61 } else { /* scale a and b by 2^68 */ 62 ha += 0x22000000; /* a *= 2^68 */ 63 hb += 0x22000000; /* b *= 2^68 */ 64 k -= 68; 65 SET_FLOAT_WORD(a,ha); 66 SET_FLOAT_WORD(b,hb); 67 } 68 } 69 /* medium size a and b */ 70 w = a-b; 71 if (w>b) { 72 SET_FLOAT_WORD(t1,ha&0xfffff000); 73 t2 = a-t1; 74 w = __ieee754_sqrtf(t1*t1-(b*(-b)-t2*(a+t1))); 75 } else { 76 a = a+a; 77 SET_FLOAT_WORD(y1,hb&0xfffff000); 78 y2 = b - y1; 79 SET_FLOAT_WORD(t1,ha+0x00800000); 80 t2 = a - t1; 81 w = __ieee754_sqrtf(t1*y1-(w*(-w)-(t1*y2+t2*b))); 82 } 83 if(k!=0) { 84 SET_FLOAT_WORD(t1,0x3f800000+(k<<23)); 85 return t1*w; 86 } else return w; 87 } 88