Mark Poliakov
7a0d528cda
git-subtree-dir: lib/runtime git-subtree-mainline: 566a2341f5b726d86f5d42a72beb9c70b83f31b6 git-subtree-split: db5cddbec10c4b7c086eda716d48d4711632901f
66 lines
1.6 KiB
C
66 lines
1.6 KiB
C
#include <stdint.h>
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#include "private.h"
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float
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__ieee754_hypotf(float x, float y)
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{
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float a=x,b=y,t1,t2,yy1,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 &= 0x7fffffff;
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GET_FLOAT_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_FLOAT_WORD(a,ha); /* a <- |a| */
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SET_FLOAT_WORD(b,hb); /* b <- |b| */
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if((ha-hb)>0xf000000) {return a+b;} /* x/y > 2**30 */
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k=0;
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if(ha > 0x58800000) { /* a>2**50 */
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if(ha >= 0x7f800000) { /* Inf or NaN */
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w = a+b; /* for sNaN */
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if(ha == 0x7f800000) w = a;
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if(hb == 0x7f800000) w = b;
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return w;
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}
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/* scale a and b by 2**-60 */
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ha -= 0x5d800000; hb -= 0x5d800000; k += 60;
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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 < 0x26800000) { /* b < 2**-50 */
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if(hb <= 0x007fffff) { /* subnormal b or 0 */
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if(hb==0) return a;
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SET_FLOAT_WORD(t1,0x3f000000); /* 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 2^60 */
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ha += 0x5d800000; /* a *= 2^60 */
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hb += 0x5d800000; /* b *= 2^60 */
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k -= 60;
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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&0xfffff000);
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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(yy1,hb&0xfffff000);
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y2 = b - yy1;
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SET_FLOAT_WORD(t1,ha+0x00800000);
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t2 = a - t1;
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w = __ieee754_sqrtf(t1*yy1-(w*(-w)-(t1*y2+t2*b)));
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}
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if(k!=0) {
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SET_FLOAT_WORD(t1,0x3f800000+(k<<23));
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return t1*w;
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} else return w;
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}
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