| 426 | |
| 427 | |
| 428 | void bitrv2conj(int n, float *a) |
| 429 | { |
| 430 | int j0, k0, j1, k1, l, m, i, j, k, nh; |
| 431 | float xr, xi, yr, yi; |
| 432 | |
| 433 | m = 4; |
| 434 | for (l = n >> 2; l > 8; l >>= 2) { |
| 435 | m <<= 1; |
| 436 | } |
| 437 | nh = n >> 1; |
| 438 | if (l == 8) { |
| 439 | j0 = 0; |
| 440 | for (k0 = 0; k0 < m; k0 += 4) { |
| 441 | k = k0; |
| 442 | for (j = j0; j < j0 + k0; j += 4) { |
| 443 | xr = a[j]; |
| 444 | xi = -a[j + 1]; |
| 445 | yr = a[k]; |
| 446 | yi = -a[k + 1]; |
| 447 | a[j] = yr; |
| 448 | a[j + 1] = yi; |
| 449 | a[k] = xr; |
| 450 | a[k + 1] = xi; |
| 451 | j1 = j + m; |
| 452 | k1 = k + 2 * m; |
| 453 | xr = a[j1]; |
| 454 | xi = -a[j1 + 1]; |
| 455 | yr = a[k1]; |
| 456 | yi = -a[k1 + 1]; |
| 457 | a[j1] = yr; |
| 458 | a[j1 + 1] = yi; |
| 459 | a[k1] = xr; |
| 460 | a[k1 + 1] = xi; |
| 461 | j1 += m; |
| 462 | k1 -= m; |
| 463 | xr = a[j1]; |
| 464 | xi = -a[j1 + 1]; |
| 465 | yr = a[k1]; |
| 466 | yi = -a[k1 + 1]; |
| 467 | a[j1] = yr; |
| 468 | a[j1 + 1] = yi; |
| 469 | a[k1] = xr; |
| 470 | a[k1 + 1] = xi; |
| 471 | j1 += m; |
| 472 | k1 += 2 * m; |
| 473 | xr = a[j1]; |
| 474 | xi = -a[j1 + 1]; |
| 475 | yr = a[k1]; |
| 476 | yi = -a[k1 + 1]; |
| 477 | a[j1] = yr; |
| 478 | a[j1 + 1] = yi; |
| 479 | a[k1] = xr; |
| 480 | a[k1 + 1] = xi; |
| 481 | j1 += nh; |
| 482 | k1 += 2; |
| 483 | xr = a[j1]; |
| 484 | xi = -a[j1 + 1]; |
| 485 | yr = a[k1]; |