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 1.7 1999/07/02 15:37:39 simonb Exp $"); 19 #endif 20 21 #include "math.h" 22 #include "math_private.h" 23 24 #ifdef __STDC__ 25 float __ieee754_hypotf(float x, float y) 26 #else 27 float __ieee754_hypot(x,y) 28 float x, y; 29 #endif 30 { 31 float a=x,b=y,t1,t2,y1,y2,w; 32 int32_t j,k,ha,hb; 33 34 GET_FLOAT_WORD(ha,x); 35 ha &= 0x7fffffff; 36 GET_FLOAT_WORD(hb,y); 37 hb &= 0x7fffffff; 38 if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;} 39 SET_FLOAT_WORD(a,ha); /* a <- |a| */ 40 SET_FLOAT_WORD(b,hb); /* b <- |b| */ 41 if((ha-hb)>0xf000000) {return a+b;} /* x/y > 2**30 */ 42 k=0; 43 if(ha > 0x58800000) { /* a>2**50 */ 44 if(ha >= 0x7f800000) { /* Inf or NaN */ 45 w = a+b; /* for sNaN */ 46 if(ha == 0x7f800000) w = a; 47 if(hb == 0x7f800000) w = b; 48 return w; 49 } 50 /* scale a and b by 2**-60 */ 51 ha -= 0x5d800000; hb -= 0x5d800000; k += 60; 52 SET_FLOAT_WORD(a,ha); 53 SET_FLOAT_WORD(b,hb); 54 } 55 if(hb < 0x26800000) { /* b < 2**-50 */ 56 if(hb <= 0x007fffff) { /* subnormal b or 0 */ 57 if(hb==0) return a; 58 SET_FLOAT_WORD(t1,0x3f000000); /* t1=2^126 */ 59 b *= t1; 60 a *= t1; 61 k -= 126; 62 } else { /* scale a and b by 2^60 */ 63 ha += 0x5d800000; /* a *= 2^60 */ 64 hb += 0x5d800000; /* b *= 2^60 */ 65 k -= 60; 66 SET_FLOAT_WORD(a,ha); 67 SET_FLOAT_WORD(b,hb); 68 } 69 } 70 /* medium size a and b */ 71 w = a-b; 72 if (w>b) { 73 SET_FLOAT_WORD(t1,ha&0xfffff000); 74 t2 = a-t1; 75 w = __ieee754_sqrtf(t1*t1-(b*(-b)-t2*(a+t1))); 76 } else { 77 a = a+a; 78 SET_FLOAT_WORD(y1,hb&0xfffff000); 79 y2 = b - y1; 80 SET_FLOAT_WORD(t1,ha+0x00800000); 81 t2 = a - t1; 82 w = __ieee754_sqrtf(t1*y1-(w*(-w)-(t1*y2+t2*b))); 83 } 84 if(k!=0) { 85 SET_FLOAT_WORD(t1,0x3f800000+(k<<23)); 86 return t1*w; 87 } else return w; 88 } 89