| 1 | /* e_hypotf.c -- float version of e_hypot.c.
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| 2 | * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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| 3 | */
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| 4 |
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| 5 | /*
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| 6 | * ====================================================
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| 7 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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| 8 | *
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| 9 | * Developed at SunPro, a Sun Microsystems, Inc. business.
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| 10 | * Permission to use, copy, modify, and distribute this
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| 11 | * software is freely granted, provided that this notice
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| 12 | * is preserved.
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| 13 | * ====================================================
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| 14 | */
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| 15 |
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| 16 | #ifndef lint
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| 17 | static char rcsid[] = "$FreeBSD: src/lib/msun/src/e_hypotf.c,v 1.9 2002/05/28 18:15:03 alfred Exp $";
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| 18 | #endif
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| 19 |
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| 20 | #include "math.h"
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| 21 | #include "math_private.h"
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| 22 |
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| 23 | float
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| 24 | __ieee754_hypotf(float x, float y)
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| 25 | {
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| 26 | float a=x,b=y,t1,t2,y1,y2,w;
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| 27 | int32_t j,k,ha,hb;
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| 28 |
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| 29 | GET_FLOAT_WORD(ha,x);
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| 30 | ha &= 0x7fffffff;
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| 31 | GET_FLOAT_WORD(hb,y);
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| 32 | hb &= 0x7fffffff;
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| 33 | if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;}
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| 34 | SET_FLOAT_WORD(a,ha); /* a <- |a| */
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| 35 | SET_FLOAT_WORD(b,hb); /* b <- |b| */
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| 36 | if((ha-hb)>0xf000000) {return a+b;} /* x/y > 2**30 */
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| 37 | k=0;
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| 38 | if(ha > 0x58800000) { /* a>2**50 */
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| 39 | if(ha >= 0x7f800000) { /* Inf or NaN */
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| 40 | w = a+b; /* for sNaN */
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| 41 | if(ha == 0x7f800000) w = a;
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| 42 | if(hb == 0x7f800000) w = b;
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| 43 | return w;
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| 44 | }
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| 45 | /* scale a and b by 2**-68 */
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| 46 | ha -= 0x22000000; hb -= 0x22000000; k += 68;
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| 47 | SET_FLOAT_WORD(a,ha);
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| 48 | SET_FLOAT_WORD(b,hb);
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| 49 | }
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| 50 | if(hb < 0x26800000) { /* b < 2**-50 */
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| 51 | if(hb <= 0x007fffff) { /* subnormal b or 0 */
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| 52 | if(hb==0) return a;
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| 53 | SET_FLOAT_WORD(t1,0x7e800000); /* t1=2^126 */
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| 54 | b *= t1;
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| 55 | a *= t1;
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| 56 | k -= 126;
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| 57 | } else { /* scale a and b by 2^68 */
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| 58 | ha += 0x22000000; /* a *= 2^68 */
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| 59 | hb += 0x22000000; /* b *= 2^68 */
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| 60 | k -= 68;
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| 61 | SET_FLOAT_WORD(a,ha);
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| 62 | SET_FLOAT_WORD(b,hb);
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| 63 | }
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| 64 | }
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| 65 | /* medium size a and b */
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| 66 | w = a-b;
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| 67 | if (w>b) {
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| 68 | SET_FLOAT_WORD(t1,ha&0xfffff000);
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| 69 | t2 = a-t1;
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| 70 | w = __ieee754_sqrtf(t1*t1-(b*(-b)-t2*(a+t1)));
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| 71 | } else {
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| 72 | a = a+a;
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| 73 | SET_FLOAT_WORD(y1,hb&0xfffff000);
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| 74 | y2 = b - y1;
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| 75 | SET_FLOAT_WORD(t1,ha+0x00800000);
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| 76 | t2 = a - t1;
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| 77 | w = __ieee754_sqrtf(t1*y1-(w*(-w)-(t1*y2+t2*b)));
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| 78 | }
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| 79 | if(k!=0) {
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| 80 | SET_FLOAT_WORD(t1,0x3f800000+(k<<23));
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| 81 | return t1*w;
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| 82 | } else return w;
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| 83 | }
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