| 1 | /* ef_hypot.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 | #include "fdlibm.h" |
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| 17 | |
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| 18 | #ifdef __STDC__ |
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| 19 | float __ieee754_hypotf(float x, float y) |
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| 20 | #else |
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| 21 | float __ieee754_hypotf(x,y) |
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| 22 | float x, y; |
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| 23 | #endif |
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| 24 | { |
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| 25 | float a=x,b=y,t1,t2,y1,y2,w; |
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| 26 | __int32_t j,k,ha,hb; |
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| 27 | |
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| 28 | GET_FLOAT_WORD(ha,x); |
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| 29 | ha &= 0x7fffffffL; |
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| 30 | GET_FLOAT_WORD(hb,y); |
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| 31 | hb &= 0x7fffffffL; |
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| 32 | if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;} |
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| 33 | SET_FLOAT_WORD(a,ha); /* a <- |a| */ |
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| 34 | SET_FLOAT_WORD(b,hb); /* b <- |b| */ |
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| 35 | if((ha-hb)>0xf000000L) {return a+b;} /* x/y > 2**30 */ |
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| 36 | k=0; |
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| 37 | if(ha > 0x58800000L) { /* a>2**50 */ |
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| 38 | if(!FLT_UWORD_IS_FINITE(ha)) { /* Inf or NaN */ |
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| 39 | w = a+b; /* for sNaN */ |
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| 40 | if(FLT_UWORD_IS_INFINITE(ha)) w = a; |
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| 41 | if(FLT_UWORD_IS_INFINITE(hb)) w = b; |
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| 42 | return w; |
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| 43 | } |
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| 44 | /* scale a and b by 2**-68 */ |
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| 45 | ha -= 0x22000000L; hb -= 0x22000000L; k += 68; |
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| 46 | SET_FLOAT_WORD(a,ha); |
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| 47 | SET_FLOAT_WORD(b,hb); |
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| 48 | } |
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| 49 | if(hb < 0x26800000L) { /* b < 2**-50 */ |
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| 50 | if(FLT_UWORD_IS_ZERO(hb)) { |
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| 51 | return a; |
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| 52 | } else if(FLT_UWORD_IS_SUBNORMAL(hb)) { |
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| 53 | SET_FLOAT_WORD(t1,0x7e800000L); /* 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&0xfffff000L); |
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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&0xfffff000L); |
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| 74 | y2 = b - y1; |
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| 75 | SET_FLOAT_WORD(t1,ha+0x00800000L); |
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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(t1,0x3f800000L+(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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