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comparison libgsmhr1/dtx_rxfe.c @ 577:d68b2c92464a

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libgsmhr1: bring in parts of dtx.[ch] needed for RxFE
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 13 Feb 2025 03:06:11 +0000
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children 7756b23b78cd
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576:94f0cc85ad50 577:d68b2c92464a
1 /*
2 * Here we implement the subset of DTX functions that are used by the Rx
3 * front end, i.e., the part of libgsmhr1 that is common between the full
4 * decoder and our TFO transform implementation. Note that the same DTX
5 * functions will also be used by the speech encoder.
6 */
7
8 #include "typedefs.h"
9 #include "namespace.h"
10 #include "dtx_rxfe.h"
11 #include "mathhalf.h"
12 #include "mathdp31.h"
13
14 /* relevant definitions from original dtx.c */
15
16 #define PN_XOR_REG (Longword)0x00000005L
17 #define PN_XOR_ADD (Longword)0x40000000L
18
19 #define OH_SHIFT 3 /* shift corresponding to OVERHANG */
20
21 /* Values of GS for voicing state 0, all values shifted down by 2
22 shifts */
23 const LongwordRom ppLr_gsTable[4][32] =
24 {
25 {
26 0x000011ab, 0x000038d2, 0x0000773e, 0x000144ef,
27 0x00035675, 0x000648c5, 0x000c3d65, 0x0017ae17,
28 0x002a3dbb, 0x005238e7, 0x00695c1a, 0x00a60d45,
29 0x00e4cc68, 0x01c3ba6a, 0x019e3c96, 0x02d1fbac,
30 0x030453ec, 0x0549a998, 0x05190298, 0x08258920,
31 0x08daff30, 0x0c3150e0, 0x0e45d850, 0x14c111a0,
32 0x0ff7e1c0, 0x18a06860, 0x13810400, 0x1abc9ee0,
33 0x28500940, 0x41f22800, 0x22fc5040, 0x2cd90180
34 },
35
36 {
37 0x00003ede, 0x00021fc9, 0x0013f0c3, 0x003a7be2,
38 0x007a6663, 0x00fe3773, 0x012fabf4, 0x02275cd0,
39 0x01c0ef14, 0x02c0b1d8, 0x0350fc70, 0x05505078,
40 0x04175f30, 0x052c1098, 0x08ed3310, 0x0a63b470,
41 0x05417870, 0x08995ee0, 0x07bbe018, 0x0a19fa10,
42 0x0b5818c0, 0x0fd96ea0, 0x0e5cad10, 0x13b40d40,
43 0x12d45840, 0x14577320, 0x2b2e5e00, 0x333e9640,
44 0x194c35c0, 0x1c30f8c0, 0x2d16db00, 0x2cc970ff
45 },
46 {
47 0x002f18e7, 0x00a47be0, 0x01222efe, 0x01c42df8,
48 0x024be794, 0x03424c40, 0x036950fc, 0x04973108,
49 0x038405b4, 0x05d8c8f0, 0x05063e08, 0x070cdea0,
50 0x05812be8, 0x06da5fc8, 0x088fcd60, 0x0a013cb0,
51 0x0909a460, 0x09e6cf40, 0x0ee581d0, 0x0ec99f20,
52 0x0b4e7470, 0x0c730e80, 0x0ff39d20, 0x105d0d80,
53 0x158b0b00, 0x172babe0, 0x14576460, 0x181a6720,
54 0x26126e80, 0x1f590180, 0x1fdaad60, 0x2e0e8000
55 },
56 {
57 0x00c7f603, 0x01260cda, 0x01b3926a, 0x026d82bc,
58 0x0228fba0, 0x036ec5b0, 0x034bf4cc, 0x043a55d0,
59 0x044f9c20, 0x05c66f50, 0x0515f890, 0x06065300,
60 0x0665dc00, 0x0802b630, 0x0737a1c0, 0x087294e0,
61 0x09253fc0, 0x0a619760, 0x097bd060, 0x0a6d4e50,
62 0x0d19e520, 0x0e15c420, 0x0c4e4eb0, 0x0e8880e0,
63 0x11cdf480, 0x12c85800, 0x10f4c0a0, 0x13e51b00,
64 0x189dbaa0, 0x18a6bb60, 0x22e31500, 0x21615240
65 }
66 };
67
68 /*************************************************************************
69 *
70 * FUNCTION NAME: avgGsHistQntz
71 *
72 * PURPOSE:
73 *
74 * Average gs history, where history is of length OVERHANG-1
75 * frames. The last frame's (i.e. this frame) gs values are not
76 * available since quantization would have occured only after the
77 * VAD decision is made.
78 *
79 * INPUTS:
80 *
81 * pL_GsHistory[(OVERHANG-1)*N_SUB] - the GS of the past
82 * OVERHANG-1 frames. The GS values are stored shifted down by 2
83 * shifts to avoid overflow (the largest GS is greater than 2.0).
84 *
85 *
86 * OUTPUTS:
87 *
88 * *pL_GsAvgd - the average of pL_GsHistory[], also shifted down
89 * by two shifts.
90 *
91 * RETURN VALUE:
92 *
93 * none.
94 *
95 *
96 *************************************************************************/
97
98 void avgGsHistQntz(Longword pL_GsHistory[], Longword *pL_GsAvgd)
99 {
100
101 /*_________________________________________________________________________
102 | |
103 | Automatic Variables |
104 |_________________________________________________________________________|
105 */
106
107 int i;
108 Longword L_avg;
109
110 /*_________________________________________________________________________
111 | |
112 | Executable Code |
113 |_________________________________________________________________________|
114 */
115
116 L_avg = L_shift_r(pL_GsHistory[0], -(OH_SHIFT + 2));
117
118 for (i = 1; i < N_SUB * (OVERHANG - 1); i++)
119 L_avg = L_add(L_shift_r(pL_GsHistory[i], -(OH_SHIFT + 2)), L_avg);
120
121 /* avg number x/32 not x/28 */
122
123 *pL_GsAvgd = L_add(L_avg, L_mpy_ls(L_avg, 0x1249)); /* L_avg *= 32/28 */
124
125 }
126
127 /*************************************************************************
128 *
129 * FUNCTION NAME: gsQuant
130 *
131 * PURPOSE:
132 *
133 * Quantize a value of gs in any of the voicing modes. Input GS
134 * is a 32 bit number. The GSP0 index is returned.
135 *
136 * INPUTS:
137 *
138 * L_GsIn - 32 bit GS value, shifted down by 2 shifts.
139 *
140 * swVoicingMode - voicing level
141 *
142 * ppLr_gsTable[4][32] - Rom GS Table. (global), all GS values
143 * have been shifted down by 2 from their true value.
144 *
145 * OUTPUTS:
146 *
147 * none
148 *
149 * RETURN VALUE:
150 *
151 *
152 * GSP0 Index closest to the input value of GS.
153 *
154 *
155 *************************************************************************/
156
157 Shortword gsQuant(Longword L_GsIn, Shortword swVoicingMode)
158 {
159
160 /*_________________________________________________________________________
161 | |
162 | Automatic Variables |
163 |_________________________________________________________________________|
164 */
165
166 Shortword swGsIndex,
167 swBestGs;
168 Longword L_diff,
169 L_min = LW_MAX;
170
171
172 /*_________________________________________________________________________
173 | |
174 | Executable Code |
175 |_________________________________________________________________________|
176 */
177
178 for (swGsIndex = 0; swGsIndex < 32; swGsIndex++)
179 {
180 L_diff = L_abs(L_sub(L_GsIn, ppLr_gsTable[swVoicingMode][swGsIndex]));
181
182 if (L_sub(L_diff, L_min) < 0)
183 {
184 /* new minimum */
185 /* ----------- */
186
187 swBestGs = swGsIndex;
188 L_min = L_diff;
189
190 }
191 }
192
193 return (swBestGs);
194
195 }
196
197 /*************************************************************************
198 *
199 * FUNCTION NAME: getPnBits
200 *
201 * PURPOSE:
202 *
203 * Generate iBits pseudo-random bits using *pL_PNSeed as the
204 * pn-generators seed.
205 *
206 * INPUTS:
207 *
208 * iBits - integer indicating how many random bits to return.
209 * range [0,15], 0 yields 1 bit output
210 *
211 * *pL_PNSeed - 32 bit seed (changed by function)
212 *
213 * OUTPUTS:
214 *
215 * *pL_PNSeed - 32 bit seed, modified.
216 *
217 * RETURN VALUE:
218 *
219 * random bits in iBits LSB's.
220 *
221 *
222 * IMPLEMENTATION:
223 *
224 * implementation of x**31 + x**3 + 1 == PN_XOR_REG | PN_XOR_ADD a
225 * PN sequence generator using Longwords generating a 2**31 -1
226 * length pn-sequence.
227 *
228 *************************************************************************/
229
230 Shortword getPnBits(int iBits, Longword *pL_PNSeed)
231 {
232
233 /*_________________________________________________________________________
234 | |
235 | Automatic Variables |
236 |_________________________________________________________________________|
237 */
238
239 Shortword swPnBits = 0;
240 Longword L_Taps,
241 L_FeedBack;
242 int i;
243
244 /*_________________________________________________________________________
245 | |
246 | Executable Code |
247 |_________________________________________________________________________|
248 */
249
250 for (i = 0; i < iBits; i++)
251 {
252 /* update the state */
253 /* ---------------- */
254
255 L_Taps = *pL_PNSeed & PN_XOR_REG;
256 L_FeedBack = L_Taps; /* Xor tap bits to yield
257 * feedback bit */
258 L_Taps = L_shr(L_Taps, 1);
259
260 while (L_Taps)
261 {
262 L_FeedBack = L_FeedBack ^ L_Taps;
263 L_Taps = L_shr(L_Taps, 1);
264 }
265
266 /* LSB of L_FeedBack is next MSB of PN register */
267
268 *pL_PNSeed = L_shr(*pL_PNSeed, 1);
269 if (L_FeedBack & 1)
270 *pL_PNSeed = *pL_PNSeed | PN_XOR_ADD;
271
272 /* State update complete. Get the output bit from the state, add/or it
273 * into output */
274
275 swPnBits = shl(swPnBits, 1);
276 swPnBits = swPnBits | (extract_l(*pL_PNSeed) & 0x0001);
277
278 }
279 return (swPnBits);
280 }