Sieve of Eratosthenes MD

This is the first MD ROM I've written from scratch. It's a simple Sieve of Eratosthenes implemented in C.



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I've gotta say thanks to Stef for the great DevKit I used to make this. It's the first one I've come across that I've been actually able to compile shit with

Have some source;

Code (Text):

1. #include "genesis.h"
2. #include "x.h"
3.  
4. const u16 pal_yellow[16] =
5. {
6.     0x0000,
7.     0x0022,
8.     0x0044,
9.     0x0066,
10.     0x0088,
11.     0x00AA,
12.     0x00CC,
13.     0x00EE,
14.  
15.     0x0EEE,
16.     0x0EEE,
17.     0x0EEE,
18.     0x0EEE,
19.     0x0EEE,
20.     0x0EEE,
21.     0x0EEE,
22.     0x0EEE
23. };
24.  
25. static void eratosthenes();
26.  
27. int main()
28. {
29.     VDP_setPalette(0, pal_yellow);
30.     VDP_drawText(APLAN, "Sieve of Eratosthenes MD", 0x8000, 1, 1);
31.     VDP_drawText(APLAN, "by  snkenjoi", 0x8000, 24, 25);
32.     setBitmapMode(BITMAP_WIDTH, BITMAP_HEIGHT);
33.     loadGenBmp16ToBitmap(x, 21, 10, 0x10);
34.     eratosthenes();
35.     return 0;
36. }
37.  
38. void eratosthenes()
39. {
40.     char str[255];
41.     int I,k,j = 0;
42.     int arr[15999]; //15999
43.     int max = (sizeof(arr)/sizeof(arr[0]));
44.  
45.  
46. &nbsp;&nbsp;&nbsp;&nbsp;for (I = 0;I<max;I+=2) {
47. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;arr[I] = 1;
48. &nbsp;&nbsp;&nbsp;&nbsp;}
49. &nbsp;&nbsp;&nbsp;&nbsp;
50. &nbsp;&nbsp;&nbsp;&nbsp;VDP_drawText(APLAN, "2", 0x8000, 1, 2);
51. &nbsp;&nbsp;&nbsp;&nbsp;
52. &nbsp;&nbsp;&nbsp;&nbsp;for (k = 0;k<max;k++){
53. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (I = 0;I<max;I++) {
54. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if(arr[I] == 0) {arr[I] = 1; j = I;wait(5000);intToStr(I+2, str, 1);VDP_drawText(APLAN, str, 0x8000, 1, 2);break;}
55. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
56. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (I = j;I<max;I+=j+2) { arr[I] = 1; }
57. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (j*j>max+2){break;}
58. &nbsp;&nbsp;&nbsp;&nbsp;}
59. &nbsp;&nbsp;&nbsp;&nbsp;for (I = 0;I<max;I++) {
60. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if(arr[I] == 0) {arr[I] = 1;wait(5000);intToStr(I+2, str, 1);VDP_drawText(APLAN, str, 0x8000, 1, 2);};
61. &nbsp;&nbsp;&nbsp;&nbsp;}
62. }

Maybe I'll make something useful next time