| /* ------------------------------------------------------------------ |
| * Copyright (C) 1998-2009 PacketVideo |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either |
| * express or implied. |
| * See the License for the specific language governing permissions |
| * and limitations under the License. |
| * ------------------------------------------------------------------- |
| */ |
| /**************************************************************************************** |
| Portions of this file are derived from the following 3GPP standard: |
| |
| 3GPP TS 26.073 |
| ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec |
| Available from http://www.3gpp.org |
| |
| (C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC) |
| Permission to distribute, modify and use this file under the standard license |
| terms listed above has been obtained from the copyright holder. |
| ****************************************************************************************/ |
| /* |
| ------------------------------------------------------------------------------ |
| |
| |
| |
| Filename: /audio/gsm_amr/c/src/g_code.c |
| |
| Date: 01/31/2002 |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| Description: The return of L_mult was being stored in a Word16 before it was |
| being operated on (extract_h). Data loss happened here. |
| |
| Description: |
| 1. Eliminated unused include files. |
| 2. Replaced array addressing by pointers |
| 3. Eliminated math operations that unnecessary checked for |
| saturation, in some cases this by shifting before adding and |
| in other cases by evaluating the operands |
| 4. Unrolled loops to speed up processing |
| 5. Eliminated calls to shifts left and right functions by adding |
| if-else statements that do the same faster. |
| |
| Description: Added casting to eliminate warnings |
| |
| Description: Replaced "int" and/or "char" with OSCL defined types. |
| |
| Description: 1. Using inlines from fxp_arithmetic.h |
| 2. Removing a compiler warning. |
| |
| Description: Replacing fxp_arithmetic.h with basic_op.h. |
| |
| Description: |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| #include "g_code.h" |
| #include "cnst.h" |
| #include "basic_op.h" |
| /*---------------------------------------------------------------------------- |
| ; MACROS |
| ; [Define module specific macros here] |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; DEFINES |
| ; [Include all pre-processor statements here. Include conditional |
| ; compile variables also.] |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL FUNCTION DEFINITIONS |
| ; [List function prototypes here] |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL VARIABLE DEFINITIONS |
| ; [Variable declaration - defined here and used outside this module] |
| ----------------------------------------------------------------------------*/ |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: G_code |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| xn2[] = target vector (Word16) |
| y2[] = filtered innovation vector |
| pOverflow = pointer to overflow (Flag) |
| |
| Outputs: |
| pOverflow -> 1 if the innovative gain calculation resulted in overflow |
| |
| Returns: |
| gain = Gain of Innovation code (Word16) |
| |
| Global Variables Used: |
| None |
| |
| Local Variables Needed: |
| None |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| This function computes the innovative codebook gain. |
| |
| The innovative codebook gain is given by |
| g = <x[], y[]> / <y[], y[]> |
| |
| where x[] is the target vector, y[] is the filtered innovative codevector, |
| and <> denotes dot product. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| [1] g_code.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| Word16 G_code ( // out : Gain of innovation code |
| Word16 xn2[], // in : target vector |
| Word16 y2[] // in : filtered innovation vector |
| ) |
| { |
| Word16 i; |
| Word16 xy, yy, exp_xy, exp_yy, gain; |
| Word16 scal_y2[L_SUBFR]; |
| Word32 s; |
| |
| // The original ETSI implementation uses a global overflow flag. However in |
| // actual implementation a pointer to Overflow flag is passed into the |
| // function for access by the low level math functions. |
| |
| // Scale down Y[] by 2 to avoid overflow |
| |
| for (i = 0; i < L_SUBFR; i++) |
| { |
| scal_y2[i] = shr (y2[i], 1); |
| } |
| |
| // Compute scalar product <X[],Y[]> |
| |
| s = 1L; // Avoid case of all zeros |
| for (i = 0; i < L_SUBFR; i++) |
| { |
| s = L_mac (s, xn2[i], scal_y2[i]); |
| } |
| exp_xy = norm_l (s); |
| xy = extract_h (L_shl (s, exp_xy)); |
| |
| // If (xy < 0) gain = 0 |
| |
| if (xy <= 0) |
| return ((Word16) 0); |
| |
| // Compute scalar product <Y[],Y[]> |
| |
| s = 0L; |
| for (i = 0; i < L_SUBFR; i++) |
| { |
| s = L_mac (s, scal_y2[i], scal_y2[i]); |
| } |
| exp_yy = norm_l (s); |
| yy = extract_h (L_shl (s, exp_yy)); |
| |
| // compute gain = xy/yy |
| |
| xy = shr (xy, 1); // Be sure xy < yy |
| gain = div_s (xy, yy); |
| |
| // Denormalization of division |
| i = add (exp_xy, 5); // 15-1+9-18 = 5 |
| i = sub (i, exp_yy); |
| |
| gain = shl (shr (gain, i), 1); // Q0 -> Q1/ |
| |
| return (gain); |
| } |
| |
| |
| ------------------------------------------------------------------------------ |
| RESOURCES USED [optional] |
| |
| When the code is written for a specific target processor the |
| the resources used should be documented below. |
| |
| HEAP MEMORY USED: x bytes |
| |
| STACK MEMORY USED: x bytes |
| |
| CLOCK CYCLES: (cycle count equation for this function) + (variable |
| used to represent cycle count for each subroutine |
| called) |
| where: (cycle count variable) = cycle count for [subroutine |
| name] |
| |
| ------------------------------------------------------------------------------ |
| CAUTION [optional] |
| [State any special notes, constraints or cautions for users of this function] |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| /*---------------------------------------------------------------------------- |
| ; FUNCTION CODE |
| ----------------------------------------------------------------------------*/ |
| Word16 G_code( /* o : Gain of innovation code */ |
| Word16 xn2[], /* i : target vector */ |
| Word16 y2[], /* i : filtered innovation vector */ |
| Flag *pOverflow /* i/o : overflow flag */ |
| ) |
| { |
| Word16 i; |
| Word16 xy, yy, exp_xy, exp_yy, gain; |
| Word32 s; |
| |
| Word16 *p_xn2 = xn2; |
| Word16 *p_y2 = y2; |
| Word16 temp; |
| Word32 temp2; |
| |
| OSCL_UNUSED_ARG(pOverflow); |
| |
| /* Compute scalar product <X[],Y[]> */ |
| s = 0; |
| |
| for (i = (L_SUBFR >> 2); i != 0 ; i--) |
| { |
| temp2 = (Word32)(*(p_y2++) >> 1); |
| s = amrnb_fxp_mac_16_by_16bb((Word32) * (p_xn2++), temp2, s); |
| temp2 = (Word32)(*(p_y2++) >> 1); |
| s = amrnb_fxp_mac_16_by_16bb((Word32) * (p_xn2++), temp2, s); |
| temp2 = (Word32)(*(p_y2++) >> 1); |
| s = amrnb_fxp_mac_16_by_16bb((Word32) * (p_xn2++), temp2, s); |
| temp2 = (Word32)(*(p_y2++) >> 1); |
| s = amrnb_fxp_mac_16_by_16bb((Word32) * (p_xn2++), temp2, s); |
| } |
| s <<= 1; |
| exp_xy = norm_l(s + 1); /* Avoid case of all zeros, add 1 */ |
| |
| if (exp_xy < 17) /* extra right shift to be sure xy < yy */ |
| { |
| xy = (Word16)(s >> (17 - exp_xy)); |
| } |
| else |
| { |
| xy = (Word16)(s << (exp_xy - 17)); |
| } |
| |
| /* If (xy < 0) gain = 0 */ |
| |
| if (xy <= 0) |
| { |
| return ((Word16) 0); |
| } |
| |
| /* Compute scalar product <Y[],Y[]> */ |
| |
| s = 0L; |
| p_y2 = y2; |
| |
| for (i = (L_SUBFR >> 1); i != 0 ; i--) |
| { |
| temp = *(p_y2++) >> 1; |
| s += ((Word32) temp * temp) >> 2; |
| temp = *(p_y2++) >> 1; |
| s += ((Word32) temp * temp) >> 2; |
| } |
| s <<= 3; |
| exp_yy = norm_l(s); |
| |
| if (exp_yy < 16) |
| { |
| yy = (Word16)(s >> (16 - exp_yy)); |
| } |
| else |
| { |
| yy = (Word16)(s << (exp_yy - 16)); |
| } |
| |
| gain = div_s(xy, yy); |
| |
| /* Denormalization of division */ |
| i = exp_xy + 5; /* 15-1+9-18 = 5 */ |
| i -= exp_yy; |
| |
| // gain = shl (shr (gain, i), 1); /* Q0 -> Q1 */ |
| |
| if (i > 1) |
| { |
| gain >>= i - 1; |
| } |
| else |
| { |
| gain <<= 1 - i; |
| } |
| |
| |
| return (gain); |
| } |
