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 #if defined(LIBM_SCCS) && !defined(lint) 18 __RCSID("$NetBSD: e_hypotf.c,v 1.9 2008/04/25 22:21:53 christos Exp $"); 19 #endif 20 21 #include "math.h" 22 #include "math_private.h" 23 24 float 25 __ieee754_hypotf(float x, float y) 26 { 27 float a=x,b=y,t1,t2,yy1,y2,w; 28 int32_t j,k,ha,hb; 29 30 GET_FLOAT_WORD(ha,x); 31 ha &= 0x7fffffff; 32 GET_FLOAT_WORD(hb,y); 33 hb &= 0x7fffffff; 34 if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;} 35 SET_FLOAT_WORD(a,ha); /* a <- |a| */ 36 SET_FLOAT_WORD(b,hb); /* b <- |b| */ 37 if((ha-hb)>0xf000000) {return a+b;} /* x/y > 2**30 */ 38 k=0; 39 if(ha > 0x58800000) { /* a>2**50 */ 40 if(ha >= 0x7f800000) { /* Inf or NaN */ 41 w = a+b; /* for sNaN */ 42 if(ha == 0x7f800000) w = a; 43 if(hb == 0x7f800000) w = b; 44 return w; 45 } 46 /* scale a and b by 2**-60 */ 47 ha -= 0x5d800000; hb -= 0x5d800000; k += 60; 48 SET_FLOAT_WORD(a,ha); 49 SET_FLOAT_WORD(b,hb); 50 } 51 if(hb < 0x26800000) { /* b < 2**-50 */ 52 if(hb <= 0x007fffff) { /* subnormal b or 0 */ 53 if(hb==0) return a; 54 SET_FLOAT_WORD(t1,0x3f000000); /* t1=2^126 */ 55 b *= t1; 56 a *= t1; 57 k -= 126; 58 } else { /* scale a and b by 2^60 */ 59 ha += 0x5d800000; /* a *= 2^60 */ 60 hb += 0x5d800000; /* b *= 2^60 */ 61 k -= 60; 62 SET_FLOAT_WORD(a,ha); 63 SET_FLOAT_WORD(b,hb); 64 } 65 } 66 /* medium size a and b */ 67 w = a-b; 68 if (w>b) { 69 SET_FLOAT_WORD(t1,ha&0xfffff000); 70 t2 = a-t1; 71 w = __ieee754_sqrtf(t1*t1-(b*(-b)-t2*(a+t1))); 72 } else { 73 a = a+a; 74 SET_FLOAT_WORD(yy1,hb&0xfffff000); 75 y2 = b - yy1; 76 SET_FLOAT_WORD(t1,ha+0x00800000); 77 t2 = a - t1; 78 w = __ieee754_sqrtf(t1*yy1-(w*(-w)-(t1*y2+t2*b))); 79 } 80 if(k!=0) { 81 SET_FLOAT_WORD(t1,0x3f800000+(k<<23)); 82 return t1*w; 83 } else return w; 84 } 85