diff options
Diffstat (limited to 'libFDK/src/FDK_lpc.cpp')
| -rw-r--r-- | libFDK/src/FDK_lpc.cpp | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/libFDK/src/FDK_lpc.cpp b/libFDK/src/FDK_lpc.cpp index 2ba7707..7d7e691 100644 --- a/libFDK/src/FDK_lpc.cpp +++ b/libFDK/src/FDK_lpc.cpp @@ -184,12 +184,19 @@ void CLpc_SynthesisLattice(FIXP_DBL *signal, const int signal_size, for (i = signal_size; i != 0; i--) { FIXP_DBL *pState = state + order - 1; const FIXP_DBL *pCoeff = coeff + order - 1; - FIXP_DBL tmp; + FIXP_DBL tmp, accu; + + accu = + fMultSubDiv2(scaleValue(*pSignal, signal_e - 1), *pCoeff--, *pState--); + tmp = SATURATE_LEFT_SHIFT_ALT(accu, 1, DFRACT_BITS); - tmp = scaleValue(*pSignal, signal_e) - fMult(*pCoeff--, *pState--); for (j = order - 1; j != 0; j--) { - tmp = tmp - fMult(pCoeff[0], pState[0]); - pState[1] = pState[0] + fMult(*pCoeff--, tmp); + accu = fMultSubDiv2(tmp >> 1, pCoeff[0], pState[0]); + tmp = SATURATE_LEFT_SHIFT_ALT(accu, 1, DFRACT_BITS); + + accu = fMultAddDiv2(pState[0] >> 1, *pCoeff--, tmp); + pState[1] = SATURATE_LEFT_SHIFT_ALT(accu, 1, DFRACT_BITS); + pState--; } |