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nuclear@0
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1 #define FB_ADDR ((unsigned char*)0x4000)
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2 #define ATTR_ADDR ((unsigned char*)0x5800)
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3 #define LINESKIP (256 / 8)
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4
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5 unsigned char mbrot(int px, int py);
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6
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7 int main()
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8 {
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9 unsigned int i, j, k, start;
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10
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11 for(;;) {
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12 start = 0;
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13
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14 for(i=0; i<192; i++) {
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15 unsigned int banky = i & 0x3f;
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16 unsigned int cell = banky / 8;
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17 unsigned int cline = banky % 8;
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18 unsigned int memline = cell + cline * 8;
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19 unsigned char *ptr = FB_ADDR + (start + memline) * LINESKIP;
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20
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21 for(j=0; j<32; j++) { /* 256 pixels, 8 pixels per byte */
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22 unsigned char pixel = 0;
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23 for(k=0; k<8; k++) {
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24 unsigned char res = mbrot((j << 3) + k, i);
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25 pixel = pixel | (res & 1);
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26 if(k < 7) pixel <<= 1;
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27 }
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28 *ptr++ = pixel;
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29 }
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30
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31 if((i & 0x3f) == 0x3f) {
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32 start += 0x40;
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33 }
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34 }
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35 }
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36 }
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37
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38 #define int2fix8_8(i) ((i) << 8)
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39 #define fix_mul8_8(a, b) ((a >> 4) * (b >> 4))
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40 #define int2fix5_11(i) ((i) << 11)
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41 #define fix_mul5_11(a, b) ((a >> 5) * (b >> 6))
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42
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43 unsigned char mbrot(int px, int py)
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44 {
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45 unsigned char i;
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46 int cx, cy, zx, zy, x, y, len;
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47
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48 cx = int2fix8_8(px - 192) >> 6;
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49 cy = int2fix8_8(py - 96) >> 6;
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50
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51 cx <<= 3;
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52 cy <<= 3;
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53
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54 zx = cx;
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55 zy = cy;
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56
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57 for(i=0; i<32; i++) {
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58 x = fix_mul5_11(zx, zx) - fix_mul5_11(zy, zy) + cx;
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59 y = fix_mul5_11(zy, zx) + fix_mul5_11(zx, zy) + cy;
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60 len = fix_mul5_11(x, x) + fix_mul5_11(y, y);
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61
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62 if(len > int2fix5_11(4)) return 0;
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63
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64 zx = x;
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65 zy = y;
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66 }
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67
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68 return 1;
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69 }
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