| 1 | /* |
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| 2 | Operace v pevne radove carce |
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| 3 | |
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| 4 | 9.10.2005 |
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| 5 | */ |
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| 6 | |
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| 7 | |
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| 8 | #include "fixed.h" |
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| 9 | |
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| 10 | long prevod(double x, unsigned int posun); |
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| 11 | // prevod "x" do systemu "Qposun" |
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| 12 | double zprevod(long x, unsigned int posun); |
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| 13 | // prevod "x" ze systemu "Qposun" do DOUBLE |
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| 14 | long nasob(int x, int y,unsigned int posun); |
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| 15 | // (x*y)>>posun |
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| 16 | int deleni15(int x, int y); |
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| 17 | // (x*Q15/y) se saturaci |
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| 18 | int deleni(int x, int y, int posun1, int posun2, int scale, int posun_fin); |
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| 19 | // obecne deleni: x_"Qposun1"*"Qscale"/y_"Qposun2" -> "Q_posun_fin" |
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| 20 | |
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| 21 | |
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| 22 | long prevod(double x, unsigned int posun) |
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| 23 | { |
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| 24 | long y,nasobic; |
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| 25 | int znamenko; |
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| 26 | |
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| 27 | nasobic=(long)1<<posun; |
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| 28 | if (x>=0) znamenko=1; |
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| 29 | else znamenko=-1; |
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| 30 | y=(long)(x*nasobic+znamenko*0.5); |
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| 31 | |
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| 32 | return y; |
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| 33 | } |
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| 34 | |
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| 35 | double zprevod(long x, unsigned int posun) |
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| 36 | { |
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| 37 | long nasobic; |
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| 38 | double y; |
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| 39 | |
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| 40 | nasobic=(long)1<<posun; |
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| 41 | y=(double)x/nasobic; |
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| 42 | |
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| 43 | return y; |
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| 44 | } |
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| 45 | |
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| 46 | long nasob(int x, int y,unsigned int posun) |
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| 47 | { |
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| 48 | long z,zaokrouhl; // zaokrouhl ... zaokrouhlovani vysledku pricteni 0.5 |
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| 49 | int znamenko; |
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| 50 | |
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| 51 | if (posun>0) |
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| 52 | zaokrouhl=(long)1<<(posun-1); |
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| 53 | else zaokrouhl=0; |
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| 54 | z=(long)x*y; |
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| 55 | if (z>=0) znamenko=1; |
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| 56 | else znamenko=-1; |
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| 57 | z=(z+znamenko*zaokrouhl)>>posun; |
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| 58 | |
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| 59 | return z; |
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| 60 | } |
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| 61 | |
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| 62 | int deleni15(int x, int y) // deleni Q15/Q15 se saturaci |
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| 63 | { |
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| 64 | long z; |
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| 65 | |
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| 66 | z=(long)x*32768/y; |
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| 67 | if (z>32767) z=32767; |
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| 68 | if (z<-32768) z=-32768; |
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| 69 | |
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| 70 | return (int)z; |
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| 71 | } |
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| 72 | |
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| 73 | int deleni(int x, int y, int posun1, int posun2, int scale, int posun_fin) |
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| 74 | /* |
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| 75 | x/y ... podil |
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| 76 | posun1 ... posun x (scale faktor) |
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| 77 | posun2 ... posun y |
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| 78 | scale ... posun pri deleni - pomocny |
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| 79 | posun_fin ... system, ve kterem ma byt vysledek (scale faktor vysledku) |
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| 80 | */ |
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| 81 | { |
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| 82 | int z; |
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| 83 | int bit_posun; |
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| 84 | long zz, scale_fakt, scale_fin; |
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| 85 | |
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| 86 | scale_fakt=(long)1<<scale; |
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| 87 | bit_posun=(posun1+scale-posun2)-posun_fin; |
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| 88 | |
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| 89 | zz=(long)x*scale_fakt/y; |
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| 90 | |
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| 91 | if (bit_posun>=0) |
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| 92 | zz=(int)(zz>>bit_posun); |
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| 93 | else |
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| 94 | { bit_posun*=-1; |
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| 95 | zz=(int)(zz<<bit_posun); |
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| 96 | } |
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| 97 | |
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| 98 | // Saturace vystupu |
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| 99 | if (zz>32767) |
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| 100 | z=32767; |
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| 101 | else if (zz<-32768) |
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| 102 | z=-32768; |
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| 103 | else |
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| 104 | z=zz; |
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| 105 | |
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| 106 | return z; |
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| 107 | } |
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