1 /* ------------------------------------------------------------------
2  * Copyright (C) 1998-2009 PacketVideo
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
13  * express or implied.
14  * See the License for the specific language governing permissions
15  * and limitations under the License.
16  * -------------------------------------------------------------------
17  */
18 /****************************************************************************************
19 Portions of this file are derived from the following 3GPP standard:
20 
21     3GPP TS 26.073
22     ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
23     Available from http://www.3gpp.org
24 
25 (C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
26 Permission to distribute, modify and use this file under the standard license
27 terms listed above has been obtained from the copyright holder.
28 ****************************************************************************************/
29 /*
30  Pathname: ./audio/gsm-amr/c/src/q_plsf_5.c
31  Funtions:
32 
33 ------------------------------------------------------------------------------
34  REVISION HISTORY
35 
36  Description: Placed code in the PV standard template format.
37  Updated to accept new parameter, Flag *pOverflow.
38 
39  Description:
40               Eliminated unused include files.
41               For Vq_subvec()
42               1. Eliminated math operations that unnecessary checked for
43                  saturation (number are bounded to 2^12)
44               2. Eliminated access to (slow) memory by using axiliar variables
45               3. Because this routine is looking for the minimum distance,
46                  introduced 3 check conditions inside the loop, so when the
47                  partial distance is bigger than the minimun distance, the
48                  loop is not completed and process continue with next iteration
49               For Vq_subvec_s()
50               1. Eliminated math operations that unnecessary checked for
51                  saturation (number are bounded to 2^12)
52               2. Combined increasing and decreasing loops to avoid double
53                  accesses to the same table element
54               3. Eliminated access to (slow) memory by using axiliar variables
55               4. Because this routine is looking for the minimum distance,
56                  introduced 2 check conditions inside the loop, so when the
57                  partial distance is bigger than the minimun distance, the
58                  loop is not completed and process continue with next iteration
59               For Q_plsf_5()
60               1. Eliminated math operations that unnecessary checked for
61                  saturation (number are bounded to 2^12)
62               2. Replaced array addressing by pointers
63 
64  Description:  Replaced OSCL mem type functions and eliminated include
65                files that now are chosen by OSCL definitions
66 
67  Description:  Replaced "int" and/or "char" with OSCL defined types.
68 
69 
70  Description: Added #ifdef __cplusplus around extern'ed table.
71 
72  Who:                           Date:
73  Description:
74 
75 ------------------------------------------------------------------------------
76  MODULE DESCRIPTION
77 
78 
79 ------------------------------------------------------------------------------
80 */
81 
82 /*----------------------------------------------------------------------------
83 ; INCLUDES
84 ----------------------------------------------------------------------------*/
85 #include "q_plsf.h"
86 #include "typedef.h"
87 #include "basic_op.h"
88 #include "lsp_lsf.h"
89 #include "reorder.h"
90 #include "lsfwt.h"
91 
92 /*--------------------------------------------------------------------------*/
93 #ifdef __cplusplus
94 extern "C"
95 {
96 #endif
97 
98     /*----------------------------------------------------------------------------
99     ; MACROS
100     ; Define module specific macros here
101     ----------------------------------------------------------------------------*/
102 
103     /*----------------------------------------------------------------------------
104     ; DEFINES
105     ; Include all pre-processor statements here. Include conditional
106     ; compile variables also.
107     ----------------------------------------------------------------------------*/
108 
109     /*----------------------------------------------------------------------------
110     ; LOCAL FUNCTION DEFINITIONS
111     ; Function Prototype declaration
112     ----------------------------------------------------------------------------*/
113 
114     /*----------------------------------------------------------------------------
115     ; LOCAL VARIABLE DEFINITIONS
116     ; Variable declaration - defined here and used outside this module
117     ----------------------------------------------------------------------------*/
118 
119     /*----------------------------------------------------------------------------
120     ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
121     ; Declare variables used in this module but defined elsewhere
122     ----------------------------------------------------------------------------*/
123     /* Codebooks of LSF prediction residual */
124     extern const Word16 mean_lsf_5[];
125 
126     extern const Word16 dico1_lsf_5[];
127     extern const Word16 dico2_lsf_5[];
128     extern const Word16 dico3_lsf_5[];
129     extern const Word16 dico4_lsf_5[];
130     extern const Word16 dico5_lsf_5[];
131 
132     /*--------------------------------------------------------------------------*/
133 #ifdef __cplusplus
134 }
135 #endif
136 
137 /*
138 ------------------------------------------------------------------------------
139  FUNCTION NAME: Vq_subvec
140 ------------------------------------------------------------------------------
141  INPUT AND OUTPUT DEFINITIONS
142 
143  Inputs:
144     lsf_r1 -- array of type Word16 -- 1st LSF residual vector,  Q15
145     lsf_r2 -- array of type Word16 -- 2nd LSF residual vector,  Q15
146     dico -- pointer to const Word16 -- quantization codebook,   Q15
147     wf1 -- array of type Word16 -- 1st LSF weighting factors,   Q13
148     wf2 -- array of type Word16 -- 2nd LSF weighting factors,   Q13
149     dico_size -- Word16 -- size of quantization codebook,       Q0
150  Outputs:
151     pOverflow -- pointer to type Flag -- overflow indicator
152 
153  Returns:
154     Word16 -- quantization index, Q0
155 
156  Global Variables Used:
157     None
158 
159  Local Variables Needed:
160     None
161 
162 ------------------------------------------------------------------------------
163  FUNCTION DESCRIPTION
164 
165  This function performs the quantization of a 4-dimensional subvector.
166 
167 ------------------------------------------------------------------------------
168  REQUIREMENTS
169 
170  None
171 
172 ------------------------------------------------------------------------------
173  REFERENCES
174 
175  q_plsf_5.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
176 
177 ------------------------------------------------------------------------------
178  PSEUDO-CODE
179 
180 
181 ------------------------------------------------------------------------------
182  RESOURCES USED [optional]
183 
184  When the code is written for a specific target processor the
185  the resources used should be documented below.
186 
187  HEAP MEMORY USED: x bytes
188 
189  STACK MEMORY USED: x bytes
190 
191  CLOCK CYCLES: (cycle count equation for this function) + (variable
192                 used to represent cycle count for each subroutine
193                 called)
194      where: (cycle count variable) = cycle count for [subroutine
195                                      name]
196 
197 ------------------------------------------------------------------------------
198  CAUTION [optional]
199  [State any special notes, constraints or cautions for users of this function]
200 
201 ------------------------------------------------------------------------------
202 */
203 /* Quantization of a 4 dimensional subvector */
204 
Vq_subvec(Word16 * lsf_r1,Word16 * lsf_r2,const Word16 * dico,Word16 * wf1,Word16 * wf2,Word16 dico_size,Flag * pOverflow)205 static Word16 Vq_subvec( /* o : quantization index,            Q0  */
206     Word16 *lsf_r1,      /* i : 1st LSF residual vector,       Q15 */
207     Word16 *lsf_r2,      /* i : 2nd LSF residual vector,       Q15 */
208     const Word16 *dico,  /* i : quantization codebook,         Q15 */
209     Word16 *wf1,         /* i : 1st LSF weighting factors      Q13 */
210     Word16 *wf2,         /* i : 2nd LSF weighting factors      Q13 */
211     Word16 dico_size,    /* i : size of quantization codebook, Q0  */
212     Flag   *pOverflow    /* o : overflow indicator                 */
213 )
214 {
215     Word16 index = 0; /* initialization only needed to keep gcc silent */
216     Word16 i;
217     Word16 temp;
218     const Word16 *p_dico;
219     Word32 dist_min;
220     Word32 dist;
221     Word16 wf1_0;
222     Word16 wf1_1;
223     Word16 wf2_0;
224     Word16 wf2_1;
225     Word32 aux1;
226     Word32 aux2;
227     Word32 aux3;
228     Word32 aux4;
229 
230     OSCL_UNUSED_ARG(pOverflow);
231 
232     dist_min = MAX_32;
233     p_dico = dico;
234 
235     wf1_0 = wf1[0];
236     wf1_1 = wf1[1];
237     wf2_0 = wf2[0];
238     wf2_1 = wf2[1];
239 
240     aux1 = ((Word32) lsf_r1[0] * wf1_0);
241     aux2 = ((Word32) lsf_r1[1] * wf1_1);
242     aux3 = ((Word32) lsf_r2[0] * wf2_0);
243     aux4 = ((Word32) lsf_r2[1] * wf2_1);
244 
245     for (i = 0; i < dico_size; i++)
246     {
247         temp  = (aux1 - ((Word32)wf1_0 * *(p_dico++))) >> 15;
248         dist  = ((Word32)temp * temp);
249 
250         if (dist >= dist_min)
251         {
252             p_dico += 3;
253             continue;
254         }
255 
256         temp  = (aux2 - ((Word32)wf1_1 * *(p_dico++))) >> 15;
257         dist += ((Word32)temp * temp);
258 
259         if (dist >= dist_min)
260         {
261             p_dico += 2;
262             continue;
263         }
264 
265         temp  = (aux3 - ((Word32)wf2_0 * *(p_dico++))) >> 15;
266         dist += ((Word32)temp * temp);
267 
268         if (dist >= dist_min)
269         {
270             p_dico += 1;
271             continue;
272         }
273 
274         temp  = (aux4 - ((Word32)wf2_1 * *(p_dico++))) >> 15;
275         dist += ((Word32)temp * temp);
276 
277 
278         if (dist < dist_min)
279         {
280             dist_min = dist;
281             index = i;
282         }
283     }
284 
285 
286 
287     /* Reading the selected vector */
288 
289     p_dico = &dico[ index<<2];
290     lsf_r1[0] = *p_dico++;
291     lsf_r1[1] = *p_dico++;
292     lsf_r2[0] = *p_dico++;
293     lsf_r2[1] = *p_dico;
294 
295     return index;
296 
297 }
298 
299 
300 /*
301 ------------------------------------------------------------------------------
302  FUNCTION NAME: Vq_subvec_s
303 ------------------------------------------------------------------------------
304  INPUT AND OUTPUT DEFINITIONS
305 
306  Inputs:
307     lsf_r1 -- array of type Word16 -- 1st LSF residual vector,  Q15
308     lsf_r2 -- array of type Word16 -- 2nd LSF residual vector,  Q15
309     dico -- pointer to const Word16 -- quantization codebook,   Q15
310     wf1 -- array of type Word16 -- 1st LSF weighting factors,   Q13
311     wf2 -- array of type Word16 -- 2nd LSF weighting factors,   Q13
312     dico_size -- Word16 -- size of quantization codebook,       Q0
313 
314  Outputs:
315     pOverflow -- pointer to type Flag -- overflow indicator
316 
317  Returns:
318     Word16 -- quantization index, Q0
319 
320  Global Variables Used:
321     None
322 
323  Local Variables Needed:
324     None
325 
326 ------------------------------------------------------------------------------
327  FUNCTION DESCRIPTION
328 
329  This function performs the quantization of a 4-dimensional subvector.
330 
331 ------------------------------------------------------------------------------
332  REQUIREMENTS
333 
334  None
335 
336 ------------------------------------------------------------------------------
337  REFERENCES
338 
339  q_plsf_5.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
340 
341 ------------------------------------------------------------------------------
342  PSEUDO-CODE
343 
344 
345 ------------------------------------------------------------------------------
346  RESOURCES USED [optional]
347 
348  When the code is written for a specific target processor the
349  the resources used should be documented below.
350 
351  HEAP MEMORY USED: x bytes
352 
353  STACK MEMORY USED: x bytes
354 
355  CLOCK CYCLES: (cycle count equation for this function) + (variable
356                 used to represent cycle count for each subroutine
357                 called)
358      where: (cycle count variable) = cycle count for [subroutine
359                                      name]
360 
361 ------------------------------------------------------------------------------
362  CAUTION [optional]
363  [State any special notes, constraints or cautions for users of this function]
364 
365 ------------------------------------------------------------------------------
366 */
367 
368 
369 /* Quantization of a 4 dimensional subvector with a signed codebook */
370 
Vq_subvec_s(Word16 * lsf_r1,Word16 * lsf_r2,const Word16 * dico,Word16 * wf1,Word16 * wf2,Word16 dico_size,Flag * pOverflow)371 static Word16 Vq_subvec_s(  /* o : quantization index            Q0  */
372     Word16 *lsf_r1,         /* i : 1st LSF residual vector       Q15 */
373     Word16 *lsf_r2,         /* i : and LSF residual vector       Q15 */
374     const Word16 *dico,     /* i : quantization codebook         Q15 */
375     Word16 *wf1,            /* i : 1st LSF weighting factors     Q13 */
376     Word16 *wf2,            /* i : 2nd LSF weighting factors     Q13 */
377     Word16 dico_size,       /* i : size of quantization codebook Q0  */
378     Flag   *pOverflow)      /* o : overflow indicator                */
379 {
380     Word16 index = 0;  /* initialization only needed to keep gcc silent */
381     Word16 sign = 0;   /* initialization only needed to keep gcc silent */
382     Word16 i;
383     Word16 temp;
384     Word16 temp1;
385     Word16 temp2;
386     const Word16 *p_dico;
387     Word32 dist_min;
388     Word32 dist1;
389     Word32 dist2;
390 
391     Word16 lsf_r1_0;
392     Word16 lsf_r1_1;
393     Word16 lsf_r2_0;
394     Word16 lsf_r2_1;
395 
396     Word16 wf1_0;
397     Word16 wf1_1;
398     Word16 wf2_0;
399     Word16 wf2_1;
400 
401     OSCL_UNUSED_ARG(pOverflow);
402 
403     dist_min = MAX_32;
404     p_dico = dico;
405 
406 
407     lsf_r1_0 = lsf_r1[0];
408     lsf_r1_1 = lsf_r1[1];
409     lsf_r2_0 = lsf_r2[0];
410     lsf_r2_1 = lsf_r2[1];
411 
412     wf1_0 = wf1[0];
413     wf1_1 = wf1[1];
414     wf2_0 = wf2[0];
415     wf2_1 = wf2[1];
416 
417     for (i = 0; i < dico_size; i++)
418     {
419         /* test positive */
420         temp = *p_dico++;
421         temp1 = lsf_r1_0 - temp;
422         temp2 = lsf_r1_0 + temp;
423         temp1 = ((Word32)wf1_0 * temp1) >> 15;
424         temp2 = ((Word32)wf1_0 * temp2) >> 15;
425         dist1 = ((Word32)temp1 * temp1);
426         dist2 = ((Word32)temp2 * temp2);
427 
428         temp = *p_dico++;
429         temp1 = lsf_r1_1 - temp;
430         temp2 = lsf_r1_1 + temp;
431         temp1 = ((Word32)wf1_1 * temp1) >> 15;
432         temp2 = ((Word32)wf1_1 * temp2) >> 15;
433         dist1 += ((Word32)temp1 * temp1);
434         dist2 += ((Word32)temp2 * temp2);
435 
436         if ((dist1 >= dist_min) && (dist2 >= dist_min))
437         {
438             p_dico += 2;
439             continue;
440         }
441 
442         temp = *p_dico++;
443         temp1 = lsf_r2_0 - temp;
444         temp2 = lsf_r2_0 + temp;
445         temp1 = ((Word32)wf2_0 * temp1) >> 15;
446         temp2 = ((Word32)wf2_0 * temp2) >> 15;
447         dist1 += ((Word32)temp1 * temp1);
448         dist2 += ((Word32)temp2 * temp2);
449 
450         temp = *p_dico++;
451         temp1 = lsf_r2_1 - temp;
452         temp2 = lsf_r2_1 + temp;
453         temp1 = ((Word32)wf2_1 * temp1) >> 15;
454         temp2 = ((Word32)wf2_1 * temp2) >> 15;
455         dist1 += ((Word32)temp1 * temp1);
456         dist2 += ((Word32)temp2 * temp2);
457 
458         if (dist1 < dist_min)
459         {
460             dist_min = dist1;
461             index = i;
462             sign = 0;
463         }
464 
465         /* test negative */
466 
467         if (dist2 < dist_min)
468         {
469             dist_min = dist2;
470             index = i;
471             sign = 1;
472         }
473     }
474 
475     /* Reading the selected vector */
476 
477     p_dico = &dico[index<<2];
478     index <<= 1;
479     if (sign)
480     {
481         lsf_r1[0] = - (*p_dico++);
482         lsf_r1[1] = - (*p_dico++);
483         lsf_r2[0] = - (*p_dico++);
484         lsf_r2[1] = - (*p_dico);
485         index +=  1;
486     }
487     else
488     {
489         lsf_r1[0] = *p_dico++;
490         lsf_r1[1] = *p_dico++;
491         lsf_r2[0] = *p_dico++;
492         lsf_r2[1] = *p_dico;
493     }
494 
495     return index;
496 
497 }
498 
499 /*
500 ------------------------------------------------------------------------------
501  FUNCTION NAME: Q_plsf_5
502 ------------------------------------------------------------------------------
503  INPUT AND OUTPUT DEFINITIONS
504 
505 
506  Inputs:
507     st   -- pointer to Q_plsfState -- state information
508     lsp1 -- array of type Word16 -- 1st LSP vector,  Q15
509     lsp2 -- array of type Word16 -- 2nd LSP vector,  Q15
510 
511  Outputs:
512     lps1_q -- array of type Word16 -- quantized 1st LSP vector,   Q15
513     lps2_q -- array of type Word16 -- quantized 2nd LSP vector,   Q15
514     indices -- array of type Word16 -- quantization indices of 5 matrics, Q0
515     pOverflow -- pointer to type Flag -- overflow indicator
516 
517  Returns:
518     None
519 
520  Global Variables Used:
521     mean_lsf_5[];
522 
523     dico1_lsf_5[];
524     dico2_lsf_5[];
525     dico3_lsf_5[];
526     dico4_lsf_5[];
527     dico5_lsf_5[];
528 
529  Local Variables Needed:
530     None
531 
532 ------------------------------------------------------------------------------
533  FUNCTION DESCRIPTION
534 
535  PURPOSE:  Quantization of 2 sets of LSF parameters using 1st order MA
536            prediction and split by 5 matrix quantization (split-MQ)
537 
538  DESCRIPTION:
539 
540       p[i] = pred_factor*past_rq[i];   i=0,...,m-1
541       r1[i]= lsf1[i] - p[i];           i=0,...,m-1
542       r2[i]= lsf2[i] - p[i];           i=0,...,m-1
543  where:
544       lsf1[i]           1st mean-removed LSF vector.
545       lsf2[i]           2nd mean-removed LSF vector.
546       r1[i]             1st residual prediction vector.
547       r2[i]             2nd residual prediction vector.
548       past_r2q[i]       Past quantized residual (2nd vector).
549 
550  The residual vectors r1[i] and r2[i] are jointly quantized using
551  split-MQ with 5 codebooks. Each 4th dimension submatrix contains 2
552  elements from each residual vector. The 5 submatrices are as follows:
553    {r1[0], r1[1], r2[0], r2[1]};  {r1[2], r1[3], r2[2], r2[3]};
554    {r1[4], r1[5], r2[4], r2[5]};  {r1[6], r1[7], r2[6], r2[7]};
555                   {r1[8], r1[9], r2[8], r2[9]}
556 
557 ------------------------------------------------------------------------------
558  REQUIREMENTS
559 
560  None
561 
562 ------------------------------------------------------------------------------
563  REFERENCES
564 
565  q_plsf_5.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
566 
567 ------------------------------------------------------------------------------
568  PSEUDO-CODE
569 
570 
571 ------------------------------------------------------------------------------
572  RESOURCES USED [optional]
573 
574  When the code is written for a specific target processor the
575  the resources used should be documented below.
576 
577  HEAP MEMORY USED: x bytes
578 
579  STACK MEMORY USED: x bytes
580 
581  CLOCK CYCLES: (cycle count equation for this function) + (variable
582                 used to represent cycle count for each subroutine
583                 called)
584      where: (cycle count variable) = cycle count for [subroutine
585                                      name]
586 
587 ------------------------------------------------------------------------------
588  CAUTION [optional]
589  [State any special notes, constraints or cautions for users of this function]
590 
591 ------------------------------------------------------------------------------
592 */
593 
Q_plsf_5(Q_plsfState * st,Word16 * lsp1,Word16 * lsp2,Word16 * lsp1_q,Word16 * lsp2_q,Word16 * indice,Flag * pOverflow)594 void Q_plsf_5(
595     Q_plsfState *st,
596     Word16 *lsp1,      /* i : 1st LSP vector,                     Q15 */
597     Word16 *lsp2,      /* i : 2nd LSP vector,                     Q15 */
598     Word16 *lsp1_q,    /* o : quantized 1st LSP vector,           Q15 */
599     Word16 *lsp2_q,    /* o : quantized 2nd LSP vector,           Q15 */
600     Word16 *indice,    /* o : quantization indices of 5 matrices, Q0  */
601     Flag   *pOverflow  /* o : overflow indicator                      */
602 )
603 {
604     Word16 i;
605     Word16 lsf1[M];
606     Word16 lsf2[M];
607     Word16 wf1[M];
608     Word16 wf2[M];
609     Word16 lsf_p[M];
610     Word16 lsf_r1[M];
611     Word16 lsf_r2[M];
612     Word16 lsf1_q[M];
613     Word16 lsf2_q[M];
614 
615     Word16 *p_lsf_p;
616     Word16 *p_lsf1;
617     Word16 *p_lsf2;
618     Word16 *p_lsf_r1;
619     Word16 *p_lsf_r2;
620 
621     /* convert LSFs to normalize frequency domain 0..16384  */
622 
623     Lsp_lsf(lsp1, lsf1, M, pOverflow);
624     Lsp_lsf(lsp2, lsf2, M, pOverflow);
625 
626     /* Compute LSF weighting factors (Q13) */
627 
628     Lsf_wt(lsf1, wf1, pOverflow);
629     Lsf_wt(lsf2, wf2, pOverflow);
630 
631     /* Compute predicted LSF and prediction error */
632 
633     p_lsf_p  = &lsf_p[0];
634     p_lsf1   = &lsf1[0];
635     p_lsf2   = &lsf2[0];
636     p_lsf_r1 = &lsf_r1[0];
637     p_lsf_r2 = &lsf_r2[0];
638 
639     for (i = 0; i < M; i++)
640     {
641         *(p_lsf_p) = mean_lsf_5[i] +
642                      (((Word32)st->past_rq[i] * LSP_PRED_FAC_MR122) >> 15);
643 
644         *(p_lsf_r1++) = *(p_lsf1++) - *(p_lsf_p);
645         *(p_lsf_r2++) = *(p_lsf2++) - *(p_lsf_p++);
646     }
647 
648     /*---- Split-MQ of prediction error ----*/
649 
650     indice[0] = Vq_subvec(&lsf_r1[0], &lsf_r2[0], dico1_lsf_5,
651                           &wf1[0], &wf2[0], DICO1_5_SIZE, pOverflow);
652 
653     indice[1] = Vq_subvec(&lsf_r1[2], &lsf_r2[2], dico2_lsf_5,
654                           &wf1[2], &wf2[2], DICO2_5_SIZE, pOverflow);
655 
656     indice[2] = Vq_subvec_s(&lsf_r1[4], &lsf_r2[4], dico3_lsf_5,
657                             &wf1[4], &wf2[4], DICO3_5_SIZE, pOverflow);
658 
659     indice[3] = Vq_subvec(&lsf_r1[6], &lsf_r2[6], dico4_lsf_5,
660                           &wf1[6], &wf2[6], DICO4_5_SIZE, pOverflow);
661 
662     indice[4] = Vq_subvec(&lsf_r1[8], &lsf_r2[8], dico5_lsf_5,
663                           &wf1[8], &wf2[8], DICO5_5_SIZE, pOverflow);
664 
665     /* Compute quantized LSFs and update the past quantized residual */
666 
667     p_lsf_r1 = &lsf_r1[0];
668     p_lsf_r2 = &lsf_r2[0];
669     p_lsf_p  = &lsf_p[0];
670     p_lsf1   = &lsf1_q[0];
671     p_lsf2   = &lsf2_q[0];
672 
673 
674     for (i = 0; i < M; i++)
675     {
676         *(p_lsf1++) = *(p_lsf_r1++) + *(p_lsf_p);
677         *(p_lsf2++) = *(p_lsf_r2) + *(p_lsf_p++);
678         st->past_rq[i] = *(p_lsf_r2++);
679     }
680 
681     /* verification that LSFs has minimum distance of LSF_GAP */
682 
683     Reorder_lsf(lsf1_q, LSF_GAP, M, pOverflow);
684     Reorder_lsf(lsf2_q, LSF_GAP, M, pOverflow);
685 
686     /*  convert LSFs to the cosine domain */
687 
688     Lsf_lsp(lsf1_q, lsp1_q, M, pOverflow);
689     Lsf_lsp(lsf2_q, lsp2_q, M, pOverflow);
690 }
691 
692