FreeCalypso > hg > gsm-codec-lib
view libgsmefr/convolve.c @ 78:5bc228bb421e
libgsmefr: lsp_az.c compiles
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sat, 26 Nov 2022 06:54:06 +0000 |
parents | 8de2f0f9bd78 |
children |
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/************************************************************************* * * FUNCTION: Convolve * * PURPOSE: * Perform the convolution between two vectors x[] and h[] and * write the result in the vector y[]. All vectors are of length L * and only the first L samples of the convolution are computed. * * DESCRIPTION: * The convolution is given by * * y[n] = sum_{i=0}^{n} x[i] h[n-i], n=0,...,L-1 * *************************************************************************/ #include "gsm_efr.h" #include "typedef.h" #include "namespace.h" #include "basic_op.h" #include "no_count.h" #include "sig_proc.h" void Convolve ( Word16 x[], /* (i) : input vector */ Word16 h[], /* (i) : impulse response */ Word16 y[], /* (o) : output vector */ Word16 L /* (i) : vector size */ ) { Word16 i, n; Word32 s; for (n = 0; n < L; n++) { s = 0; move32 (); for (i = 0; i <= n; i++) { s = L_mac (s, x[i], h[n - i]); } s = L_shl (s, 3); y[n] = extract_h (s); move16 (); } return; }