forked from KolibriOS/kolibrios
76 lines
1.8 KiB
C
76 lines
1.8 KiB
C
#include <math.h>
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#include "fdlibm.h"
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float hypotf (float x, float y)
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{
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double a=x,b=y,t1,t2,y1,y2,w;
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__int32_t j,k,ha,hb;
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GET_HIGH_WORD(ha,x);
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ha &= 0x7fffffff;
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GET_HIGH_WORD(hb,y);
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hb &= 0x7fffffff;
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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_HIGH_WORD(a,ha); /* a <- |a| */
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SET_HIGH_WORD(b,hb); /* b <- |b| */
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if((ha-hb)>0x3c00000) {return a+b;} /* x/y > 2**60 */
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k=0;
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if(ha > 0x5f300000) { /* a>2**500 */
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if(ha >= 0x7ff00000) { /* Inf or NaN */
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__uint32_t low;
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w = a+b; /* for sNaN */
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GET_LOW_WORD(low,a);
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if(((ha&0xfffff)|low)==0) w = a;
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GET_LOW_WORD(low,b);
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if(((hb^0x7ff00000)|low)==0) w = b;
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return w;
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}
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/* scale a and b by 2**-600 */
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ha -= 0x25800000; hb -= 0x25800000; k += 600;
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SET_HIGH_WORD(a,ha);
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SET_HIGH_WORD(b,hb);
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}
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if(hb < 0x20b00000) { /* b < 2**-500 */
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if(hb <= 0x000fffff) { /* subnormal b or 0 */
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__uint32_t low;
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GET_LOW_WORD(low,b);
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if((hb|low)==0) return a;
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t1=0;
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SET_HIGH_WORD(t1,0x7fd00000); /* t1=2^1022 */
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b *= t1;
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a *= t1;
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k -= 1022;
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} else { /* scale a and b by 2^600 */
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ha += 0x25800000; /* a *= 2^600 */
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hb += 0x25800000; /* b *= 2^600 */
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k -= 600;
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SET_HIGH_WORD(a,ha);
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SET_HIGH_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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t1 = 0;
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SET_HIGH_WORD(t1,ha);
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t2 = a-t1;
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w = sqrt(t1*t1-(b*(-b)-t2*(a+t1)));
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} else {
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a = a+a;
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y1 = 0;
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SET_HIGH_WORD(y1,hb);
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y2 = b - y1;
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t1 = 0;
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SET_HIGH_WORD(t1,ha+0x00100000);
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t2 = a - t1;
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w = sqrt(t1*y1-(w*(-w)-(t1*y2+t2*b)));
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}
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if(k!=0) {
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__uint32_t high;
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t1 = 1.0;
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GET_HIGH_WORD(high,t1);
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SET_HIGH_WORD(t1,high+(k<<20));
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return t1*w;
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} else return w;
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}
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