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84 lines
2.2 KiB
C
84 lines
2.2 KiB
C
/* ef_hypot.c -- float version of e_hypot.c.
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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*/
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#include "fdlibm.h"
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#ifdef __STDC__
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float __ieee754_hypotf(float x, float y)
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#else
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float __ieee754_hypotf(x,y)
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float x, y;
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#endif
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{
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float a=x,b=y,t1,t2,y1,y2,w;
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__int32_t j,k,ha,hb;
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GET_FLOAT_WORD(ha,x);
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ha &= 0x7fffffffL;
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GET_FLOAT_WORD(hb,y);
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hb &= 0x7fffffffL;
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if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;}
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SET_FLOAT_WORD(a,ha); /* a <- |a| */
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SET_FLOAT_WORD(b,hb); /* b <- |b| */
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if((ha-hb)>0xf000000L) {return a+b;} /* x/y > 2**30 */
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k=0;
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if(ha > 0x58800000L) { /* a>2**50 */
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if(!FLT_UWORD_IS_FINITE(ha)) { /* Inf or NaN */
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w = a+b; /* for sNaN */
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if(FLT_UWORD_IS_INFINITE(ha)) w = a;
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if(FLT_UWORD_IS_INFINITE(hb)) w = b;
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return w;
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}
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/* scale a and b by 2**-68 */
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ha -= 0x22000000L; hb -= 0x22000000L; k += 68;
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SET_FLOAT_WORD(a,ha);
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SET_FLOAT_WORD(b,hb);
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}
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if(hb < 0x26800000L) { /* b < 2**-50 */
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if(FLT_UWORD_IS_ZERO(hb)) {
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return a;
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} else if(FLT_UWORD_IS_SUBNORMAL(hb)) {
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SET_FLOAT_WORD(t1,0x7e800000L); /* t1=2^126 */
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b *= t1;
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a *= t1;
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k -= 126;
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} else { /* scale a and b by 2^68 */
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ha += 0x22000000; /* a *= 2^68 */
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hb += 0x22000000; /* b *= 2^68 */
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k -= 68;
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SET_FLOAT_WORD(a,ha);
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SET_FLOAT_WORD(b,hb);
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}
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}
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/* medium size a and b */
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w = a-b;
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if (w>b) {
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SET_FLOAT_WORD(t1,ha&0xfffff000L);
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t2 = a-t1;
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w = __ieee754_sqrtf(t1*t1-(b*(-b)-t2*(a+t1)));
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} else {
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a = a+a;
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SET_FLOAT_WORD(y1,hb&0xfffff000L);
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y2 = b - y1;
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SET_FLOAT_WORD(t1,ha+0x00800000L);
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t2 = a - t1;
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w = __ieee754_sqrtf(t1*y1-(w*(-w)-(t1*y2+t2*b)));
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}
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if(k!=0) {
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SET_FLOAT_WORD(t1,0x3f800000L+(k<<23));
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return t1*w;
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} else return w;
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}
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