Slightly optimised reference implementation of the Mersenne Twister */
| 60 | |
| 61 | /* Slightly optimised reference implementation of the Mersenne Twister */ |
| 62 | inline unsigned long rk_random(rk_state *state) |
| 63 | { |
| 64 | unsigned long y; |
| 65 | |
| 66 | if (state->pos == RK_STATE_LEN) |
| 67 | { |
| 68 | int i; |
| 69 | |
| 70 | for (i=0;i<N-M;i++) |
| 71 | { |
| 72 | y = (state->key[i] & UPPER_MASK) | (state->key[i+1] & LOWER_MASK); |
| 73 | state->key[i] = state->key[i+M] ^ (y>>1) ^ (-(y & 1) & MATRIX_A); |
| 74 | } |
| 75 | for (;i<N-1;i++) |
| 76 | { |
| 77 | y = (state->key[i] & UPPER_MASK) | (state->key[i+1] & LOWER_MASK); |
| 78 | state->key[i] = state->key[i+(M-N)] ^ (y>>1) ^ (-(y & 1) & MATRIX_A); |
| 79 | } |
| 80 | y = (state->key[N-1] & UPPER_MASK) | (state->key[0] & LOWER_MASK); |
| 81 | state->key[N-1] = state->key[M-1] ^ (y>>1) ^ (-(y & 1) & MATRIX_A); |
| 82 | |
| 83 | state->pos = 0; |
| 84 | } |
| 85 | |
| 86 | y = state->key[state->pos++]; |
| 87 | |
| 88 | /* Tempering */ |
| 89 | y ^= (y >> 11); |
| 90 | y ^= (y << 7) & 0x9d2c5680UL; |
| 91 | y ^= (y << 15) & 0xefc60000UL; |
| 92 | y ^= (y >> 18); |
| 93 | |
| 94 | return y; |
| 95 | } |
| 96 | |
| 97 | inline double rk_double(rk_state *state) |
| 98 | { |