| /* ------------------------------------------------------------------ |
| * 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/round.c |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| Description: Created separate file for the round function. Sync'ed up |
| with the current template and fixed tabs. |
| |
| Description: Made changes based on review meeting: |
| 1. Removed long in Inputs Definitions. |
| 2. Changed L_var1 to var_out and description in |
| Output Definitions. |
| |
| Description: Added a parameter to the function interface, pOverflow which is |
| a pointer to the overflow flag. This flag is required by the |
| L_add() function invoked by round(). |
| Removed code that updates the MOPS counter. |
| Created a new return variable result. |
| |
| Description: Removed embedded tabs. Included comment in the Pseudo code |
| Section about using pointer to overflow flag in the actual |
| implementation instead of using a global flag. |
| |
| Description: Changed function name to pv_round to avoid conflict with |
| round function in C standard library. |
| |
| Who: Date: |
| Description: |
| |
| ------------------------------------------------------------------------------ |
| MODULE DESCRIPTION |
| |
| Rounding function with saturation. |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| #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: pv_round |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| L_var1 = 32 bit signed integer (Word32) whose value falls |
| in the range : 0x8000 0000 <= L_var1 <= 0x7fff ffff. |
| |
| pOverflow = pointer to overflow (Flag) |
| |
| Outputs: |
| None |
| |
| Returns: |
| result = MS 16 bits of rounded input L_var1. |
| |
| Global Variables Used: |
| None |
| |
| Local Variables Needed: |
| None |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| This function rounds the lower 16 bits of the 32 bit input number into the |
| MS 16 bits with saturation. Shift the resulting bits right by 16 and return |
| the 16 bit number: |
| pv_round(L_var1) = extract_h(L_add(L_var1,32768)) |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| [1] round() function in basic_op2.c, UMTS GSM AMR speech codec, R99 - |
| Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| Word16 pv_round (Word32 L_var1) |
| { |
| Word16 var_out; |
| Word32 L_rounded; |
| |
| * The reference ETSI code uses a global flag for Overflow in the L_add() function. |
| * In the actual implementation a pointer to Overflow flag is passed in as a |
| * parameter to the function. |
| |
| L_rounded = L_add (L_var1, (Word32) 0x00008000L); |
| #if (WMOPS) |
| multiCounter[currCounter].L_add--; |
| #endif |
| var_out = extract_h (L_rounded); |
| #if (WMOPS) |
| multiCounter[currCounter].extract_h--; |
| multiCounter[currCounter].round++; |
| #endif |
| return (var_out); |
| } |
| |
| ------------------------------------------------------------------------------ |
| 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 pv_round(register Word32 L_var1, Flag *pOverflow) |
| { |
| Word16 result; |
| |
| L_var1 = L_add(L_var1, (Word32) 0x00008000L, pOverflow); |
| result = (Word16)(L_var1 >> 16); |
| |
| return (result); |
| } |