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Rev | Author | Line No. | Line |
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4349 | Serge | 1 | |
2 | /* |
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3 | * ==================================================== |
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4 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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5 | * |
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6 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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7 | * Permission to use, copy, modify, and distribute this |
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8 | * software is freely granted, provided that this notice |
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9 | * is preserved. |
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10 | * ==================================================== |
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11 | */ |
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12 | |||
13 | |||
14 | * ceil(x) |
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15 | * Return x rounded toward -inf to integral value |
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16 | * Method: |
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17 | * Bit twiddling. |
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18 | * Exception: |
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19 | * Inexact flag raised if x not equal to ceil(x). |
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20 | */ |
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21 | |||
22 | |||
23 | |||
24 | |||
25 | |||
26 | |||
27 | static const double huge = 1.0e300; |
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28 | #else |
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29 | static double huge = 1.0e300; |
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30 | #endif |
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31 | |||
32 | |||
33 | double ceil(double x) |
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34 | #else |
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35 | double ceil(x) |
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36 | double x; |
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37 | #endif |
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38 | { |
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39 | __int32_t i0,i1,j0; |
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40 | __uint32_t i,j; |
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41 | EXTRACT_WORDS(i0,i1,x); |
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42 | j0 = ((i0>>20)&0x7ff)-0x3ff; |
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43 | if(j0<20) { |
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44 | if(j0<0) { /* raise inexact if x != 0 */ |
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45 | if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */ |
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46 | if(i0<0) {i0=0x80000000;i1=0;} |
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47 | else if((i0|i1)!=0) { i0=0x3ff00000;i1=0;} |
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48 | } |
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49 | } else { |
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50 | i = (0x000fffff)>>j0; |
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51 | if(((i0&i)|i1)==0) return x; /* x is integral */ |
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52 | if(huge+x>0.0) { /* raise inexact flag */ |
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53 | if(i0>0) i0 += (0x00100000)>>j0; |
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54 | i0 &= (~i); i1=0; |
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55 | } |
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56 | } |
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57 | } else if (j0>51) { |
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58 | if(j0==0x400) return x+x; /* inf or NaN */ |
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59 | else return x; /* x is integral */ |
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60 | } else { |
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61 | i = ((__uint32_t)(0xffffffff))>>(j0-20); |
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62 | if((i1&i)==0) return x; /* x is integral */ |
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63 | if(huge+x>0.0) { /* raise inexact flag */ |
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64 | if(i0>0) { |
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65 | if(j0==20) i0+=1; |
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66 | else { |
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67 | j = i1 + (1<<(52-j0)); |
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68 | if(j |
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69 | i1 = j; |
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70 | } |
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71 | } |
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72 | i1 &= (~i); |
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73 | } |
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74 | } |
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75 | INSERT_WORDS(x,i0,i1); |
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76 | return x; |
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77 | } |
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78 | |||
79 | |||
80 | ><(52-j0)); |