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 hypotf(float x, float y) |
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20 | #else |
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21 | float 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(ha >= 0x7f800000L) { /* Inf or NaN */ |
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39 | w = a+b; /* for sNaN */ |
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40 | if(ha == 0x7f800000L) w = a; |
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41 | if(hb == 0x7f800000L) 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**-60 */ |
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45 | ha -= 0x5d800000L; hb -= 0x5d800000L; k += 60; |
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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(hb <= 0x007fffffL) { /* subnormal b or 0 */ |
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51 | if(hb==0) return a; |
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52 | SET_FLOAT_WORD(t1,0x3f000000L); /* t1=2^126 */ |
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53 | b *= t1; |
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54 | a *= t1; |
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55 | k -= 126; |
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56 | } else { /* scale a and b by 2^60 */ |
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57 | ha += 0x5d800000; /* a *= 2^60 */ |
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58 | hb += 0x5d800000; /* b *= 2^60 */ |
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59 | k -= 60; |
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60 | SET_FLOAT_WORD(a,ha); |
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61 | SET_FLOAT_WORD(b,hb); |
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62 | } |
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63 | } |
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64 | /* medium size a and b */ |
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65 | w = a-b; |
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66 | if (w>b) { |
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67 | SET_FLOAT_WORD(t1,ha&0xfffff000L); |
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68 | t2 = a-t1; |
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69 | w = sqrtf(t1*t1-(b*(-b)-t2*(a+t1))); |
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70 | } else { |
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71 | a = a+a; |
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72 | SET_FLOAT_WORD(y1,hb&0xfffff000L); |
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73 | y2 = b - y1; |
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74 | SET_FLOAT_WORD(t1,ha+0x00800000L); |
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75 | t2 = a - t1; |
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76 | w = sqrtf(t1*y1-(w*(-w)-(t1*y2+t2*b))); |
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77 | } |
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78 | if(k!=0) { |
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79 | SET_FLOAT_WORD(t1,0x3f800000L+(k<<23)); |
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80 | return t1*w; |
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81 | } else return w; |
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82 | } |
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