Alexandre Lision | 7c6f4a6 | 2013-09-05 13:27:01 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische |
| 3 | * Universitaet Berlin. See the accompanying file "COPYRIGHT" for |
| 4 | * details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE. |
| 5 | */ |
| 6 | |
| 7 | #include <stdio.h> |
| 8 | |
| 9 | #include "gsm610_priv.h" |
| 10 | |
| 11 | /* |
| 12 | * 4.3 FIXED POINT IMPLEMENTATION OF THE RPE-LTP DECODER |
| 13 | */ |
| 14 | |
| 15 | static void Postprocessing ( |
| 16 | struct gsm_state * S, |
| 17 | register word * s) |
| 18 | { |
| 19 | register int k; |
| 20 | register word msr = S->msr; |
| 21 | register word tmp; |
| 22 | |
| 23 | for (k = 160; k--; s++) { |
| 24 | tmp = GSM_MULT_R( msr, 28180 ); |
| 25 | msr = GSM_ADD(*s, tmp); /* Deemphasis */ |
| 26 | *s = GSM_ADD(msr, msr) & 0xFFF8; /* Truncation & Upscaling */ |
| 27 | } |
| 28 | S->msr = msr; |
| 29 | } |
| 30 | |
| 31 | void Gsm_Decoder ( |
| 32 | struct gsm_state * S, |
| 33 | |
| 34 | word * LARcr, /* [0..7] IN */ |
| 35 | |
| 36 | word * Ncr, /* [0..3] IN */ |
| 37 | word * bcr, /* [0..3] IN */ |
| 38 | word * Mcr, /* [0..3] IN */ |
| 39 | word * xmaxcr, /* [0..3] IN */ |
| 40 | word * xMcr, /* [0..13*4] IN */ |
| 41 | |
| 42 | word * s) /* [0..159] OUT */ |
| 43 | { |
| 44 | int j, k; |
| 45 | word erp[40], wt[160]; |
| 46 | word * drp = S->dp0 + 120; |
| 47 | |
| 48 | for (j=0; j <= 3; j++, xmaxcr++, bcr++, Ncr++, Mcr++, xMcr += 13) { |
| 49 | |
| 50 | Gsm_RPE_Decoding( /*-S,-*/ *xmaxcr, *Mcr, xMcr, erp ); |
| 51 | Gsm_Long_Term_Synthesis_Filtering( S, *Ncr, *bcr, erp, drp ); |
| 52 | |
| 53 | for (k = 0; k <= 39; k++) wt[ j * 40 + k ] = drp[ k ]; |
| 54 | } |
| 55 | |
| 56 | Gsm_Short_Term_Synthesis_Filter( S, LARcr, wt, s ); |
| 57 | Postprocessing(S, s); |
| 58 | } |
| 59 | |