Plan 9 from Bell Labs’s /usr/web/sources/plan9/sys/src/libdraw/icossin.c

 ``` #include #include #include /* * Integer sine and cosine for integral degree argument. * Tables computed by (sin,cos)(PI*d/180). */ static short sinus[91] = { 0, /* 0 */ 18, /* 1 */ 36, /* 2 */ 54, /* 3 */ 71, /* 4 */ 89, /* 5 */ 107, /* 6 */ 125, /* 7 */ 143, /* 8 */ 160, /* 9 */ 178, /* 10 */ 195, /* 11 */ 213, /* 12 */ 230, /* 13 */ 248, /* 14 */ 265, /* 15 */ 282, /* 16 */ 299, /* 17 */ 316, /* 18 */ 333, /* 19 */ 350, /* 20 */ 367, /* 21 */ 384, /* 22 */ 400, /* 23 */ 416, /* 24 */ 433, /* 25 */ 449, /* 26 */ 465, /* 27 */ 481, /* 28 */ 496, /* 29 */ 512, /* 30 */ 527, /* 31 */ 543, /* 32 */ 558, /* 33 */ 573, /* 34 */ 587, /* 35 */ 602, /* 36 */ 616, /* 37 */ 630, /* 38 */ 644, /* 39 */ 658, /* 40 */ 672, /* 41 */ 685, /* 42 */ 698, /* 43 */ 711, /* 44 */ 724, /* 45 */ 737, /* 46 */ 749, /* 47 */ 761, /* 48 */ 773, /* 49 */ 784, /* 50 */ 796, /* 51 */ 807, /* 52 */ 818, /* 53 */ 828, /* 54 */ 839, /* 55 */ 849, /* 56 */ 859, /* 57 */ 868, /* 58 */ 878, /* 59 */ 887, /* 60 */ 896, /* 61 */ 904, /* 62 */ 912, /* 63 */ 920, /* 64 */ 928, /* 65 */ 935, /* 66 */ 943, /* 67 */ 949, /* 68 */ 956, /* 69 */ 962, /* 70 */ 968, /* 71 */ 974, /* 72 */ 979, /* 73 */ 984, /* 74 */ 989, /* 75 */ 994, /* 76 */ 998, /* 77 */ 1002, /* 78 */ 1005, /* 79 */ 1008, /* 80 */ 1011, /* 81 */ 1014, /* 82 */ 1016, /* 83 */ 1018, /* 84 */ 1020, /* 85 */ 1022, /* 86 */ 1023, /* 87 */ 1023, /* 88 */ 1024, /* 89 */ 1024, /* 90 */ }; void icossin(int deg, int *cosp, int *sinp) { int sinsign, cossign; short *stp, *ctp; deg %= 360; if(deg < 0) deg += 360; sinsign = 1; cossign = 1; stp = 0; ctp = 0; switch(deg/90){ case 2: sinsign = -1; cossign = -1; deg -= 180; /* fall through */ case 0: stp = &sinus[deg]; ctp = &sinus[90-deg]; break; case 3: sinsign = -1; cossign = -1; deg -= 180; /* fall through */ case 1: deg = 180-deg; cossign = -cossign; stp = &sinus[deg]; ctp = &sinus[90-deg]; break; } *sinp = sinsign*stp[0]; *cosp = cossign*ctp[0]; } ```