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 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**-60 */ 42 ha -= 0x5d800000; hb -= 0x5d800000; k += 60; 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(t1,0x3f000000); /* t1=2^126 */ 50 b *= t1; 51 a *= t1; 52 k -= 126; 53 } else { /* scale a and b by 2^60 */ 54 ha += 0x5d800000; /* a *= 2^60 */ 55 hb += 0x5d800000; /* b *= 2^60 */ 56 k -= 60; 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