Last change
on this file since 403 was 337, checked in by coas-nagasima, 6 years ago |
ASP3版ECNLを追加
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Property svn:eol-style
set to
native
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Property svn:mime-type
set to
text/x-csrc;charset=UTF-8
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File size:
1.3 KB
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1 | #include <math.h>
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2 | #include <stdint.h>
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3 |
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4 | float remquof(float x, float y, int *quo)
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5 | {
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6 | union {float f; uint32_t i;} ux = {x}, uy = {y};
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7 | int ex = ux.i>>23 & 0xff;
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8 | int ey = uy.i>>23 & 0xff;
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9 | int sx = ux.i>>31;
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10 | int sy = uy.i>>31;
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11 | uint32_t q;
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12 | uint32_t i;
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13 | uint32_t uxi = ux.i;
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14 |
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15 | *quo = 0;
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16 | if (uy.i<<1 == 0 || isnan(y) || ex == 0xff)
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17 | return (x*y)/(x*y);
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18 | if (ux.i<<1 == 0)
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19 | return x;
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20 |
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21 | /* normalize x and y */
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22 | if (!ex) {
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23 | for (i = uxi<<9; i>>31 == 0; ex--, i <<= 1);
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24 | uxi <<= -ex + 1;
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25 | } else {
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26 | uxi &= -1U >> 9;
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27 | uxi |= 1U << 23;
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28 | }
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29 | if (!ey) {
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30 | for (i = uy.i<<9; i>>31 == 0; ey--, i <<= 1);
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31 | uy.i <<= -ey + 1;
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32 | } else {
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33 | uy.i &= -1U >> 9;
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34 | uy.i |= 1U << 23;
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35 | }
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36 |
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37 | q = 0;
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38 | if (ex < ey) {
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39 | if (ex+1 == ey)
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40 | goto end;
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41 | return x;
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42 | }
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43 |
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44 | /* x mod y */
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45 | for (; ex > ey; ex--) {
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46 | i = uxi - uy.i;
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47 | if (i >> 31 == 0) {
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48 | uxi = i;
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49 | q++;
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50 | }
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51 | uxi <<= 1;
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52 | q <<= 1;
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53 | }
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54 | i = uxi - uy.i;
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55 | if (i >> 31 == 0) {
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56 | uxi = i;
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57 | q++;
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58 | }
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59 | if (uxi == 0)
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60 | ex = -30;
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61 | else
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62 | for (; uxi>>23 == 0; uxi <<= 1, ex--);
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63 | end:
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64 | /* scale result and decide between |x| and |x|-|y| */
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65 | if (ex > 0) {
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66 | uxi -= 1U << 23;
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67 | uxi |= (uint32_t)ex << 23;
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68 | } else {
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69 | uxi >>= -ex + 1;
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70 | }
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71 | ux.i = uxi;
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72 | x = ux.f;
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73 | if (sy)
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74 | y = -y;
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75 | if (ex == ey || (ex+1 == ey && (2*x > y || (2*x == y && q%2)))) {
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76 | x -= y;
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77 | q++;
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78 | }
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79 | q &= 0x7fffffff;
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80 | *quo = sx^sy ? -(int)q : (int)q;
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81 | return sx ? -x : x;
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82 | }
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