767 lines
25 KiB
C
767 lines
25 KiB
C
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/*
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*
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* rockwell.c
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*
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* Conversion subroutines for:
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*
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* signed linear 16 bit audio words <--> Rockwell 2, 3, or 4 bit ADPCM
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*
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* -----------------------------------------------------------------------
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*
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* Floating point version by
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* Torsten Duwe <duwe@informatik.uni-erlangen.de>
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*
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* very remotely derived from Rockwell's d.asm.
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* Converted to C and simplified by Torsten Duwe 1995
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*
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* -----------------------------------------------------------------------
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*
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* Floating point version was removed on Fri Jan 17 13:23:42 1997
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*
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* -----------------------------------------------------------------------
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*
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* Fixed point version
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* by Peter Jaeckel <atmpj@ermine.ox.ac.uk> [1996-1997].
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*
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*
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* Marc Eberhard dubbed this file the "Rocky Horror Picture Show".
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* And he is right.
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* PJ, Tue Jan 14 17:04:13 1997
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*
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*
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* The fixed point version is a complete rewrite, I reused only some
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* tiny fragments of the floating point code.
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*
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* The fixed point version actually manages to get output that is
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* identical to that of the DOS executables distributed by Rockwell. It
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* is noticeably better than that of the floating point version.
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* Rockwell uses all sorts of dirty tricks in their fixed point code
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* which I don't necessarily understand as I am not an expert on
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* compression formats. Read the comments throughout the code for
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* further explanation.
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*
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* Technical Note : The compressor does not do any silence deletion
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* which is exactly what the Rockwell sources do as well. The
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* decompressor detects silence codewords and inserts the required
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* silence period if RV_HONOUR_SILENCE_CODEWORDS is defined. Otherwise,
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* the silence codeword and the following integer word determining the
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* length of the silence are just gobbled up as compressed data and may
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* lead to some temporarily increased noise level after that.
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*
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* The Rockwell sources were taken from http://www.nb.rockwell.com/ref/adpcm.html .
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*
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* Peter Jaeckel, Fri Jan 17 14:40:32 1997
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*
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* -----------------------------------------------------------------------
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*
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* $Id: rockwell.c,v 1.6 1999/03/16 09:59:20 marcs Exp $
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*
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*/
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#define RV_HONOUR_SILENCE_CODEWORDS
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#include "../include/voice.h"
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/*
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PJ:
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A first attempt to implement basically all that the original
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Rockwell D.ASM code does in C. I never had to deal with assembler
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before, so be lenient when you judge me, please...
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NB: The guts of this code are not very pretty to look at.
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RV_ stands for Rockwell Voice.
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*/
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#define RV_PNT98 32113 /* 0.98 */
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#define RV_PNT012 393 /* 0.012 */
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#define RV_PNT006 197 /* 0.006 */
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#define RV_QDLMN 0x1F /* QDLMN = IQDLMN = 2.87 mV. */
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#define RV_DEMPCF 0x3333 /* 0.4 */
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#define RV_PDEMPCF 0x3333 /* 0.4 */
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#define RV_QORDER 8 /* Total delay line length for the pole and zero delay lines */
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/*
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Design Notes: Relation of QDataIndex to position in QData Buffer.
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the rotation is done by the QDataIndex. This variable always
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points to the data to be multiplied by the coefficient a1. The
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coefficients, a1..a2 and b1..b6, stay in the same relative
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position in the coefficient array. Updates to these values are
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done in place. Illustration belows shows the value of QDataIndex
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and the Delay Line data in relation to the coefficient array.
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Position
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in Qdata Start 2nd 3rd 4th
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-----------------------------------------
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0 a1 Y(n-1) Y(n-2) Q(n-1) Q(n-2)
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1 a2 Y(n-2) Q(n-1) Q(n-2) Q(n-3)
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2 b1 Q(n-1) Q(n-2) Q(n-3) Q(n-4)
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3 b2 Q(n-2) Q(n-3) Q(n-4) Q(n-5)
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4 b3 Q(n-3) Q(n-4) Q(n-5) Q(n-6)
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5 b4 Q(n-4) Q(n-5) Q(n-6) Y(n-1)
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6 b5 Q(n-5) Q(n-6) Y(n-1) Y(n-2)
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7 b6 Q(n-6) Y(n-1) Y(n-2) Q(n-1)
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-----------------------------------------
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QDataIndex 0 7 6 5
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-----------------------------------------
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*/
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static vgetty_s_int16 RV_pzTable[8]; /* Coefficient Table for the pole and zero linear predictor. */
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/* a1 a2 b1 b2 b3 b4 b5 b6 */
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static vgetty_s_int16 RV_QdataIndex = 0; /* Delay line pointer to the coefficient a1. */
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static vgetty_s_int16 RV_Qdata[RV_QORDER]; /* Delay line. */
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#ifdef POSTFILTER /* DON'T USE THIS */
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/*
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The POSTFILTER code is in Rockwell's original D.ASM, too.
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They too, don't use it in their distributed executables
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though. I have no idea under what circumstances it might be
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useful, I just left the code in here as I went through the
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effort of writing it before I realised that it appears to be
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useless here.
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*/
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static vgetty_s_int16 RV_QPdata[RV_QORDER];
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static vgetty_s_int16 RV_QPPdata[RV_QORDER];
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#endif
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static vgetty_s_int16 RV_LastNu = 0; /* Last Nu value. */
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static vgetty_s_int16 RV_Dempz = 0; /* De-emphasis filter delay line (one element). */
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static vgetty_s_int16 RV_NewQdata = 0; /* Adaptive quantizer output. */
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static vgetty_s_int16 RV_NewAppData = 0; /* Temporay data storage */
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/* ML2bps, ML3bps, and ML4bps are combined in mul[][], just like Torsten suggested */
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static vgetty_s_int16 RV_mul[3][16] =
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{ /* Multiplier table to calculate new Nu for 2/3/4 BPS. */
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{0x3333, 0x199A, 0x199A, 0x3333},
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{0x3800, 0x2800, 0x1CCD, 0x1CCD, 0x1CCD, 0x1CCD, 0x2800, 0x3800},
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{0x4CCD, 0x4000, 0x3333, 0x2666, 0x1CCD, 0x1CCD, 0x1CCD, 0x1CCD, 0x1CCD, 0x1CCD, 0x1CCD, 0x1CCD, 0x2666, 0x3333, 0x4000, 0x4CCD}
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};
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/* Zeta2bps, Zeta3bps, and Zeta4bps are combined in Zeta[][],
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just like Torsten suggested */
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static vgetty_u_int16 RV_Zeta[3][16] =
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{ /* Multiplier table for 2/3/4 BPS to calculate inverse */
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/* quantizer output. This number, index by the code */
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/* word, times Nu is the inverse quantizer output. */
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{0xCFAE, 0xF183, 0x0E7D, 0x3052},
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{0xBB23, 0xD4FE, 0xE7CF, 0xF828, 0x07D8, 0x1831, 0x2B02, 0x44DD},
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{0xA88B, 0xBDCB, 0xCC29, 0xD7CF, 0xE1D8, 0xEAFB, 0xF395, 0xFBE4, 0x041C, 0x0C6B, 0x1505, 0x1E28, 0x2831, 0x33C7, 0x4235, 0x5775}
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};
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static vgetty_s_int16 *RV_mul_p;
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static vgetty_s_int16 *RV_Zeta_p;
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static vgetty_u_int16 RV_silence_words[3] = {0x13ec, 0x23de, 0xc11c};
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static vgetty_u_int16 RV_silence_word;
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/* Maximum limit for Nu. Changes based on 2, 3, or 4 BPS selected.
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Initialization routine updates this value. */
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static vgetty_s_int16 RV_QDelayMX = 0;
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/* Array index by BPS-2 for updating QDelayMX */
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static vgetty_s_int16 RV_QDelayTable[3] = {0x54C4,0x3B7A,0x2ED5}; /* 2.01V, 1.41V, 1.11V */
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/*
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Macro definitions used in the decompression, interpolation, and
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compression functions.
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*/
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static vgetty_s_int32 RV_max_local_int16,RV_min_local_int16;
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static vgetty_s_int64 RV_max_local_int32,RV_min_local_int32;
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#define RV_clip_16(a) ((a)<RV_min_local_int16?RV_min_local_int16:(a)>RV_max_local_int16?RV_max_local_int16:(a))
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#define RV_clip_32(a) ((a)<RV_min_local_int32?RV_min_local_int32:(a)>RV_max_local_int32?RV_max_local_int32:(a))
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#define HIWORD(x) (((vgetty_u_int32)x) >> 16)
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#define LOWORD(x) ((vgetty_u_int32)(((unsigned int)x) & 0xffff))
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#define LOBYTE(x) ((unsigned int)(((unsigned int)x) & 0xff))
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#define RV_round_32_into_16(x) (vgetty_s_int16)((((vgetty_u_int32)x)>>16)+((((vgetty_u_int32)x)>>15)&0x0001))
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/* In order to stay as close as possible to the original assembler
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(a kludge, I know), we simulate the system's register(s) below */
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static vgetty_s_int16 RV_di;
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/* Utilities.
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Routines that both the decompressor and the compressor use. */
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/*
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pzPred
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Linear predictor coefficient update routine. Local to this module.
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Inputs:
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CX = Q(n), i.e. WORD PTR NewQData
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Output: DI points to (QDataIndex+7)%8.
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*/
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static void RV_pzPred(vgetty_s_int16 cx){
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/*
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A little explanation is required here. Rockwell uses 16bit
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integers to represent numbers in [-1,1). They take 0x8000 to be -1
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and 0x7fff to be 0.999969482, i.e. the ints -32768 to 32767 are
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normalised over 32768 into the required interval. The product of
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two such numbers is supposed to be, again, in the range [-1,1).
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I know that this is mathematically incorrect, but that's how they
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do it, just read on.
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The "adjustment" that is mentioned in D.ASM can be understood by
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the following example: Assume you want to multiply -1 with -0.5. In
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integers, that's imul 0x8000, 0xc000 (I know, it does actulally
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require a register), i.e. -32768*-16384. The result is 0x20000000.
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They only want to keep a 16 bit result, thus they need to round.
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First, however, an adjustment for the moved decimal point is
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required. The upper 16 bit of 0x20000000 are 0x2000 which
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corresponds only to 8192/32768=0.25 ! Thus, all the bits need to be
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left shifted by one place and the result will be 0x4000 which
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correctly corresponds to 0.5 now. This confusion is due to the fact
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that the original two numbers in total have two bits representing
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two different signs and the result, which is again represented by a
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total of 32 bits, needs only one sign bit. Thus, the result in 32
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bits has effectively one more data bit available than the total of
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the two multiplicands. The nature of integer arithmetics feeds that
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bit in from the left behind the sign bit. A consequence of this is
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that the two leftmost bits of the resulting 32 bit integer are
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always equal, apart from one case, namely 0x8000*0x8000, or
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-32768*-32768, which results in 0x40000000. Arithmetically, we
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would expect this to be decimal-point-adjusted to the 16 bit
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representation 0x7fff. The Rockwell assembler code, however, just
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maps this to 0x8000, i.e. -1, by ignoring the special case of
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0x8000*0x8000. This explains the cryptic warnings like
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; Determine sign of Q(n) * Y(n-1)
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;
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; Do not change the sign determination method!
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in D.ASM. Personally, this is the first time ever I have seen
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anyone using arithmetics like -1 * -1 = -1 whilst -1 * -0.99 = 0.99 ;-).
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So, after this type of decimal-point-adjustment they then round off
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the lower 16 bit and just take the upper 16 to be the result.
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*/
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static vgetty_s_int32 x,y; /* local accumulator(s) */
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static vgetty_s_int16 di;
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static int i;
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di = RV_QdataIndex;
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/* Calculate coefficients a1 a2 b1 b2 b3 b4 b5 b6 . */
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for (i = 0; i < 8; i++)
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{
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x = RV_pzTable[i] * ((vgetty_s_int32) RV_PNT98);
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x <<= 1; /*
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Rockwell-adjust for decimal point shift, then round off
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lower 16 bits to obtain a 16 bit representation of the
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result.
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*/
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x = RV_round_32_into_16 (x);
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/* cx contains the NewQdata=Q(n) */
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y = ((vgetty_s_int32) cx) * ((vgetty_s_int32) RV_Qdata[di]);
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y <<= 1; /* Rockwell-adjust for decimal point shift. */
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y = RV_round_32_into_16 (y);
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x += (y < 0 ? -1 : 1) * (i < 2 ? RV_PNT012 : RV_PNT006);
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/* i<2 ? The a's get RV_PNT012. All b's get RV_PNT006. */
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/*
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The result of a multiplication needs adjusting & rounding.
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The result of an addition/subtraction needs clipping.
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*/
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RV_pzTable[i] = RV_clip_16 (x);
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di++;
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di %= 8;
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}
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}
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/*
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Taken from D.ASM:
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Design Notes: Sum of Multiplications.
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Multiplications are 16-bit signed numbers producing a signed 32-bit
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result. The two operands are usually numbers less than one; this
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requires a 32-bit shift by the macro "adjust" to bring the decimal
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point in line. The 32-bit addition is two 16-bit additions with
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carry. The "clip" macro checks for overflow and limits the result of
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the addition to 0x7fffffff or 0x80000000 (for 32-bit results), or
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0x7fff or 0x8000 (for 16-bit results). Note that the "clip" macro
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depends on the flags being set because of an addition; the 80x86
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processor does not update these flags because of a move operation.
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*/
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static vgetty_s_int32 RV_XpzCalc(vgetty_s_int16 cx){
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/*
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Linear pole and zero predictor calculate. CX,BX register pair is the
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32 bit accumulator. Local to this module.
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Input: CX = Initial Value. BX set to zero.
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Output: CX,BX contains the result of the sum of products.
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Also, DI points to (QDataIndex+7)%8.
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*/
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static vgetty_s_int32 x; /* local accumulator */
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static vgetty_s_int64 sum;
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int i;
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RV_di = RV_QdataIndex;
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sum = ((vgetty_s_int32) cx) << 16;
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for (i = 0; i < 8; i++)
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{
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x = ((vgetty_s_int32) RV_pzTable[i]) * ((vgetty_s_int32) RV_Qdata[RV_di]);
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x <<= 1; /* Rockwell-adjust for decimal point shift. */
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sum += x;
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sum = RV_clip_32 (sum);
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RV_di++;
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RV_di %= 8;
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}
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RV_di = (RV_QdataIndex + 7) % 8;
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return (vgetty_s_int32) sum;
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}
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static void RV_Reset(int bps){
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int i;
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vgetty_u_int16 tmp_int16 = 0;
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vgetty_u_int32 tmp_int32 = 0;
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tmp_int16 = ~tmp_int16;
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tmp_int16 >>= 1;
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RV_max_local_int16 = tmp_int16;
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RV_min_local_int16 = tmp_int16;
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RV_min_local_int16 = -RV_min_local_int16;
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RV_min_local_int16--;
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tmp_int32 = ~tmp_int32;
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tmp_int32 >>= 1;
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RV_max_local_int32 = tmp_int32;
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RV_min_local_int32 = tmp_int32;
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RV_min_local_int32 = -RV_min_local_int32;
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RV_min_local_int32--;
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RV_QdataIndex = 0;
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for (i = 0; i < RV_QORDER; i++)
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{
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RV_Qdata[i] = 0;
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#ifdef POSTFILTER
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RV_QPdata[i] = 0;
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RV_QPPdata[i] = 0;
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#endif
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}
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RV_Dempz = 0;
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RV_NewQdata = 0;
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RV_NewAppData = 0;
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RV_LastNu = RV_QDLMN;
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RV_QDelayMX = RV_QDelayTable[bps-2];
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RV_silence_word = RV_silence_words[bps-2];
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RV_mul_p = RV_mul[bps-2];
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RV_Zeta_p = (vgetty_s_int16 *)RV_Zeta[bps-2];
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}
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#ifdef POSTFILTER
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static vgetty_s_int16 RV_P8Table[6] = /* Adaptive post filter number 1 coefficients */
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{0x6666, 0x51eb, 0x4189, 0x346d, 0x29f1, 0x218e};
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static vgetty_s_int16 RV_PM5Table[6] = /* Adaptive post filter number 2 coefficients */
|
||
|
{0xc000, 0xe000, 0xf000, 0xf800, 0xfc00, 0xfe00};
|
||
|
|
||
|
static vgetty_s_int32 RV_App1Calc(vgetty_s_int16 cx){
|
||
|
/* Adaptive post filter number 1 */
|
||
|
/*
|
||
|
Load pointers to the predictor table and the pointer
|
||
|
to the coefficient a1.
|
||
|
*/
|
||
|
|
||
|
static vgetty_s_int32 x; /* local accumulator */
|
||
|
static vgetty_s_int64 sum;
|
||
|
static vgetty_s_int16 di;
|
||
|
int i;
|
||
|
|
||
|
di = RV_QdataIndex;
|
||
|
RV_NewAppData = cx;
|
||
|
sum = 0;
|
||
|
|
||
|
for (i = 0; i < 8; i++)
|
||
|
{
|
||
|
x = ((vgetty_s_int32) RV_pzTable[i]) * ((vgetty_s_int32) RV_P8Table[i]);
|
||
|
x <<= 1; /*
|
||
|
Rockwell-adjust for decimal point shift, then round off
|
||
|
lower 16 bits to obtain a 16 bit representation of the
|
||
|
result.
|
||
|
*/
|
||
|
x = ((vgetty_s_int32)
|
||
|
(RV_round_32_into_16 (x))) * ((vgetty_s_int32) RV_QPdata[di]);
|
||
|
x <<= 1; /* Rockwell-adjust for decimal point shift. */
|
||
|
sum += x;
|
||
|
sum = RV_clip_32 (sum);
|
||
|
di++;
|
||
|
di %= 8;
|
||
|
}
|
||
|
cx = HIWORD(sum);
|
||
|
di = (RV_QdataIndex + 7) % 8;
|
||
|
RV_QPdata[di] = cx; /* drop b6, now a1 Qdata */
|
||
|
di += 2;
|
||
|
di %= 8;
|
||
|
RV_QPdata[di] = RV_NewAppData; /* drop a2, now b1 Qdata */
|
||
|
return (vgetty_s_int32) sum;
|
||
|
}
|
||
|
|
||
|
static vgetty_s_int32 RV_App2Calc(vgetty_s_int16 cx){
|
||
|
|
||
|
/* Adaptive post filter number 2 */
|
||
|
/*
|
||
|
Load pointers to the predictor table and the pointer
|
||
|
to the coefficient a1.
|
||
|
*/
|
||
|
|
||
|
static vgetty_s_int32 x; /* local accumulator */
|
||
|
static vgetty_s_int64 sum;
|
||
|
static vgetty_s_int16 di;
|
||
|
int i;
|
||
|
|
||
|
di = RV_QdataIndex;
|
||
|
RV_NewAppData = cx;
|
||
|
sum = 0;
|
||
|
|
||
|
for (i = 0; i < 8; i++)
|
||
|
{
|
||
|
x = ((vgetty_s_int32) RV_pzTable[i]) * ((vgetty_s_int32) RV_PM5Table[i]);
|
||
|
x <<= 1; /*
|
||
|
Rockwell-adjust for decimal point shift, then round off
|
||
|
lower 16 bits to obtain a 16 bit representation of the
|
||
|
result.
|
||
|
*/
|
||
|
x = ((vgetty_s_int32) RV_round_32_into_16 (x)) * ((vgetty_s_int32) RV_QPPdata[di]);
|
||
|
x <<= 1; /* Rockwell-adjust for decimal point shift. */
|
||
|
sum += x;
|
||
|
sum = RV_clip_32 (sum);
|
||
|
di++;
|
||
|
di %= 8;
|
||
|
}
|
||
|
cx = HIWORD(sum);
|
||
|
di = (RV_QdataIndex + 7) % 8;
|
||
|
RV_QPPdata[di] = cx; /* drop b6, now a1 Qdata */
|
||
|
di += 2;
|
||
|
di %= 8;
|
||
|
RV_QPPdata[di] = RV_NewAppData; /* drop a2, now b1 Qdata */
|
||
|
return (vgetty_s_int32) sum;
|
||
|
}
|
||
|
|
||
|
#endif
|
||
|
|
||
|
static vgetty_s_int16 RV_DecomOne(vgetty_s_int16 ax, vgetty_s_int16 bx){
|
||
|
/*
|
||
|
RVDecomOne
|
||
|
|
||
|
Decode a code word. Local to this module.
|
||
|
|
||
|
Inputs:
|
||
|
AX = ML, adaptive multiplier for Nu.
|
||
|
BX = Zeta, base inverse quantizer value, modified by Nu.
|
||
|
Also, updates QdataIndex to (QdataIndex+7)%8 .
|
||
|
*/
|
||
|
static vgetty_s_int16 si;
|
||
|
static vgetty_s_int32 LastNu_bak;
|
||
|
static vgetty_s_int32 x; /* local accumulator */
|
||
|
static vgetty_s_int64 sum;
|
||
|
|
||
|
LastNu_bak = RV_LastNu;
|
||
|
x = ((vgetty_s_int32) ax) * ((vgetty_s_int32) RV_LastNu);
|
||
|
x <<= 1; /* Rockwell-adjust for decimal point shift. */
|
||
|
/* Round and Multiply by 4 */
|
||
|
x = (RV_round_32_into_16 (x) * ((vgetty_s_int32)4));
|
||
|
RV_LastNu = RV_clip_16 (x);
|
||
|
if (RV_LastNu < RV_QDLMN)
|
||
|
RV_LastNu = RV_QDLMN;
|
||
|
else if (RV_LastNu > RV_QDelayMX)
|
||
|
RV_LastNu = RV_QDelayMX;
|
||
|
|
||
|
x = bx * LastNu_bak; /* Zeta * LastNu */
|
||
|
x <<= 1; /* Rockwell-adjust for decimal point shift. */
|
||
|
x = (RV_round_32_into_16 (x) * ((vgetty_s_int32)4));
|
||
|
RV_NewQdata = RV_clip_16 (x);
|
||
|
sum = RV_XpzCalc (RV_NewQdata); /* Compute (Xp+z)(n) + Q(n) */
|
||
|
si = HIWORD(sum); /* Y(n) done, save in SI for later */
|
||
|
#ifdef POSTFILTER
|
||
|
sum = RV_App1Calc ((vgetty_s_int16)(HIWORD(sum)));
|
||
|
sum = RV_App2Calc ((vgetty_s_int16)(HIWORD(sum)));
|
||
|
#endif
|
||
|
/* Use a de-emphasis filter on Y(n) to remove the effects */
|
||
|
/* of the emphasis filter used during compression. */
|
||
|
x = RV_DEMPCF * RV_Dempz;
|
||
|
x <<= 1; /* Rockwell-adjust for decimal point shift. */
|
||
|
sum += x;
|
||
|
sum = RV_clip_32 (sum);
|
||
|
RV_Dempz = HIWORD(sum);
|
||
|
/* Update predictor filter coefficients. */
|
||
|
RV_pzPred (RV_NewQdata);
|
||
|
RV_Qdata[RV_di] = si; /* drop b6, now a1 Qdata */
|
||
|
/* Update delay line at the a1(n) table entry position. */
|
||
|
RV_QdataIndex = RV_di;
|
||
|
RV_di += 2;
|
||
|
RV_di %= 8;
|
||
|
RV_Qdata[RV_di] = RV_NewQdata; /* drop a2, now b1 Qdata */
|
||
|
return RV_Dempz;
|
||
|
}
|
||
|
|
||
|
/* Compression!! */
|
||
|
|
||
|
/* cd2x, cd3x, and cd4x are combined in cd[][], just like Torsten suggested */
|
||
|
|
||
|
static vgetty_s_int16 RV_cdx[3][16] =
|
||
|
{
|
||
|
{0x1F69},
|
||
|
{0x1005, 0x219A, 0x37F0},
|
||
|
{0x0843, 0x10B8, 0x1996, 0x232B, 0x2DFC, 0x3B02, 0x4CD6}
|
||
|
};
|
||
|
static vgetty_s_int16 RV_cdx_length[3] = { 1,3,7 };
|
||
|
static vgetty_s_int16 *RV_cd;
|
||
|
static vgetty_s_int16 RV_cd_length;
|
||
|
|
||
|
static vgetty_s_int32 RV_ComOne(vgetty_s_int16 ax)
|
||
|
{
|
||
|
/*
|
||
|
RVComOne
|
||
|
|
||
|
Code a word into a bps bit codeword. Local to this module.
|
||
|
|
||
|
Inputs:
|
||
|
AX = X(n)
|
||
|
|
||
|
*/
|
||
|
int i;
|
||
|
static vgetty_s_int16 adc16z1 = 0; /* X(n-1) */
|
||
|
static vgetty_s_int16 NewXpz = 0; /* Xp+z(n) */
|
||
|
static vgetty_s_int16 bx,cx,dx;
|
||
|
static vgetty_s_int32 x, y; /* local accumulator */
|
||
|
static vgetty_s_int64 sum;
|
||
|
|
||
|
sum = RV_XpzCalc ((vgetty_s_int16)0); /* Compute Xp+z(n) */
|
||
|
NewXpz = HIWORD(sum);
|
||
|
x = ((vgetty_s_int32) adc16z1) * RV_PDEMPCF;
|
||
|
x <<= 1; /* Rockwell-adjust for decimal point shift. */
|
||
|
sum += x;
|
||
|
sum = RV_clip_32 (sum);
|
||
|
cx = HIWORD(sum);
|
||
|
/* Optimise any of this at your own peril ! */
|
||
|
x = cx;
|
||
|
x -= ax;
|
||
|
cx = RV_clip_16 (x);
|
||
|
bx = cx;
|
||
|
if (bx<0) bx = -bx;
|
||
|
cx = -cx;
|
||
|
adc16z1 = ax;
|
||
|
y = RV_LastNu; /*
|
||
|
Optimise any of this at your own peril !
|
||
|
Ideally, the important variables
|
||
|
here should all be declared volatile.
|
||
|
If you change any of this, your
|
||
|
optimiser might break it !
|
||
|
*/
|
||
|
for (i=0;i<RV_cd_length;i++){
|
||
|
x = ((vgetty_s_int32)RV_cd[i]) * y;
|
||
|
x <<= 1; /* Rockwell-adjust for decimal point shift. */
|
||
|
/* Round and Multiply by 4 */
|
||
|
x = (RV_round_32_into_16 (x) * ((vgetty_s_int32)4));
|
||
|
dx = RV_clip_16 (x);
|
||
|
if (bx<dx) break;
|
||
|
}
|
||
|
i++;
|
||
|
if (cx<0){
|
||
|
i -= RV_cd_length;
|
||
|
i--;
|
||
|
i = -i;
|
||
|
} else i+= RV_cd_length;
|
||
|
ax = i;
|
||
|
x = ((vgetty_s_int32)RV_mul_p[i]) * y;
|
||
|
x <<= 1; /* Rockwell-adjust for decimal point shift. */
|
||
|
/* Round and Multiply by 4 */
|
||
|
x = (RV_round_32_into_16 (x) * ((vgetty_s_int32)4));
|
||
|
RV_LastNu = RV_clip_16 (x);
|
||
|
if (RV_LastNu < RV_QDLMN)
|
||
|
RV_LastNu = RV_QDLMN;
|
||
|
else if (RV_LastNu > RV_QDelayMX)
|
||
|
RV_LastNu = RV_QDelayMX;
|
||
|
/* Make a new inverse quantizer value. */
|
||
|
x = ((vgetty_s_int32)RV_Zeta_p[i]) * y;
|
||
|
x <<= 1; /* Rockwell-adjust for decimal point shift. */
|
||
|
/* Round and Multiply by 4 */
|
||
|
x = (RV_round_32_into_16 (x) * ((vgetty_s_int32)4));
|
||
|
cx = RV_clip_16 (x);
|
||
|
/* Update predictor filter coefficients. */
|
||
|
RV_pzPred (cx);
|
||
|
/* Update delay line at the a1(n) table entry position. */
|
||
|
RV_QdataIndex += 7;
|
||
|
RV_QdataIndex %= 8;
|
||
|
x = NewXpz;
|
||
|
x += cx;
|
||
|
RV_Qdata[RV_QdataIndex] = RV_clip_16 (x); /* drop b6, now a1 Qdata. */
|
||
|
RV_Qdata[(RV_QdataIndex+2)%8] = cx; /* drop a2, now b1 Qdata. */
|
||
|
return (vgetty_s_int32) ax;
|
||
|
}
|
||
|
|
||
|
#ifdef RV_HONOUR_SILENCE_CODEWORDS /* Honour silence codewords and insert the requested silence */
|
||
|
|
||
|
static void put_silence(vgetty_s_int32 num_samples, FILE * out)
|
||
|
{
|
||
|
/* Write num_samples 16 bit ints of value 0 */
|
||
|
num_samples *= 2;
|
||
|
|
||
|
while (num_samples && (putc (0, out) != EOF))
|
||
|
num_samples--;
|
||
|
|
||
|
if (num_samples)
|
||
|
{
|
||
|
perror ("write silence");
|
||
|
exit (1);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
static int getcodeword(FILE * in, vgetty_s_int32 *codeword){
|
||
|
/*
|
||
|
Rockwell modems always pass on 16bit ints in little-endian format.
|
||
|
Therefore, we have to read the data the same way if we don't want
|
||
|
to miss a silence codeword.
|
||
|
*/
|
||
|
static int c;
|
||
|
if ((c = getc (in)) == EOF) return 0;
|
||
|
*codeword = c;
|
||
|
if ((c = getc (in)) == EOF) return 8;
|
||
|
*codeword |= (c<<8);
|
||
|
return 16;
|
||
|
}
|
||
|
|
||
|
int rockwelltopvf (FILE *fd_in, FILE *fd_out, int nbits, pvf_header *header_out)
|
||
|
{
|
||
|
vgetty_s_int32 w; /* packed compressed codewords */
|
||
|
int c; /* single compressed codeword */
|
||
|
vgetty_s_int32 mask=(1<<nbits)-1; /* bitmask for the decompression */
|
||
|
vgetty_s_int32 a = 0; /* local accumulator */
|
||
|
int valbits = 0; /* number of bits valid in accumulator */
|
||
|
|
||
|
/* The pvf header should have been written by now, start with the decompression */
|
||
|
|
||
|
/* Reset the coefficient table for the pole and zero linear predictor. */
|
||
|
for (w = 0; w < 8; w++) RV_pzTable[w] = 0;
|
||
|
RV_Reset (nbits);
|
||
|
/*
|
||
|
The algorithm below (copied from Torsten Duwe's code)
|
||
|
takes care of bit concatenation.
|
||
|
*/
|
||
|
while ((c=getcodeword(fd_in,&w)))
|
||
|
/*
|
||
|
Not using the pvf library generic read_bits interface because
|
||
|
Rockwell modems always pass on 16bit ints in little-endian format.
|
||
|
Therefore, we have to read the data the same way if we don't want
|
||
|
to miss a silence codeword.
|
||
|
*/
|
||
|
{
|
||
|
if (w == RV_silence_word)
|
||
|
{
|
||
|
getcodeword(fd_in,&w);
|
||
|
put_silence (w, fd_out);
|
||
|
RV_Reset (nbits);
|
||
|
valbits = 0;
|
||
|
continue;
|
||
|
}
|
||
|
a |= w<<valbits;
|
||
|
valbits += c;
|
||
|
while (valbits >= nbits)
|
||
|
{
|
||
|
c = a & mask;
|
||
|
w = RV_DecomOne(RV_mul_p[c],RV_Zeta_p[c]);
|
||
|
w <<= 8; /* The pvf routines expect a 24bit int */
|
||
|
header_out->write_pvf_data(fd_out, w);
|
||
|
a >>= nbits;
|
||
|
valbits -= nbits;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
return(OK);
|
||
|
}
|
||
|
|
||
|
#else /* Silence codewords are just gobbled up as data */
|
||
|
|
||
|
int rockwelltopvf (FILE *fd_in, FILE *fd_out, int nbits, pvf_header *header_out)
|
||
|
{
|
||
|
state_t s = init_state;
|
||
|
int c; /* single compressed codeword or EOF */
|
||
|
|
||
|
/* The pvf header should have been written by now, start with the decompression */
|
||
|
|
||
|
/* Reset the coefficient table for the pole and zero linear predictor. */
|
||
|
for (c = 0; c < 8; c++) RV_pzTable[c] = 0;
|
||
|
RV_Reset (nbits);
|
||
|
|
||
|
while ((c = read_bits_reverse(fd_in,&s,nbits)) != EOF)
|
||
|
header_out->write_pvf_data(fd_out, /* The pvf routines expect a 24bit int */
|
||
|
((vgetty_s_int32)RV_DecomOne(RV_mul_p[c],RV_Zeta_p[c]))<<8 );
|
||
|
|
||
|
return(OK);
|
||
|
}
|
||
|
|
||
|
#endif
|
||
|
|
||
|
int pvftorockwell (FILE *fd_in, FILE *fd_out, int nbits, pvf_header *header_in)
|
||
|
{
|
||
|
state_t s = init_state;
|
||
|
vgetty_s_int32 w; /* uncompressed audio word */
|
||
|
|
||
|
/* Reset the coefficient table for the pole and zero linear predictor. */
|
||
|
for (w = 0; w < 8; w++) RV_pzTable[w] = 0;
|
||
|
RV_Reset (nbits);
|
||
|
RV_cd = RV_cdx[nbits-2];
|
||
|
RV_cd_length = RV_cdx_length[nbits-2];
|
||
|
|
||
|
/* The rmd header should have been written by now. Do the compression. */
|
||
|
|
||
|
while (1)
|
||
|
{
|
||
|
w = header_in->read_pvf_data(fd_in);
|
||
|
if (feof(fd_in))
|
||
|
break;
|
||
|
/* The pvf routines work on 24bit ints */
|
||
|
write_bits_reverse(fd_out, &s, nbits, (int)RV_ComOne((vgetty_s_int16)(w>>8)) );
|
||
|
}
|
||
|
|
||
|
if (s.nleft > 0) write_bits_reverse(fd_out, &s, 8 - s.nleft, 0x00);
|
||
|
|
||
|
return(OK);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* I borrowed this code from wav.c - it assumes the pvf is a certain size and
|
||
|
* I'm not sure this is a good assumption -- Bill Nugent <whn@topelo.lopi.com>
|
||
|
*/
|
||
|
|
||
|
int rockwellpcmtopvf (FILE *fd_in, FILE *fd_out, int nbits, pvf_header *header_out)
|
||
|
{
|
||
|
int d;
|
||
|
/* 8 bit PCM */
|
||
|
while ((d = getc(fd_in)) != EOF)
|
||
|
{
|
||
|
d -= 0x80;
|
||
|
d <<= 16;
|
||
|
header_out->write_pvf_data(fd_out, d);
|
||
|
}
|
||
|
return(OK);
|
||
|
}
|
||
|
|
||
|
int pvftorockwellpcm (FILE *fd_in, FILE *fd_out, int nbits, pvf_header *header_in)
|
||
|
{
|
||
|
int data;
|
||
|
/* 8 bit PCM */
|
||
|
|
||
|
while((data = header_in->read_pvf_data(fd_in)) != EOF)
|
||
|
{
|
||
|
data >>=16;
|
||
|
|
||
|
if (data > 0x7f)
|
||
|
data = 0x7f;
|
||
|
|
||
|
if (data < -0x80)
|
||
|
data = -0x80;
|
||
|
putc(data+0x80,fd_out);
|
||
|
};
|
||
|
|
||
|
return(OK);
|
||
|
}
|