| /* ------------------------------------------------------------------ |
| * 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. |
| ****************************************************************************************/ |
| /* |
| |
| Pathname: ./gsm-amr/c/src/norm_s.c |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| Description: Created separate file for the norm_s function. Sync'ed up |
| with the current template and fixed tabs. |
| |
| Description: Updated input/output definition and module description to |
| be the same as the equivalent assembly file (norm_s.asm). |
| |
| Description: Updated definition of var1 to be the same as that in the |
| assembly file (norm_s.asm). |
| |
| Description: Removed conditional code that updates WMOPS counter |
| |
| Who: Date: |
| Description: |
| |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| var1 = 16 bit signed integer of type Word16, whose value falls |
| in the range: 0x8000 <= var1 <= 0x7fff |
| |
| Local Stores/Buffers/Pointers Needed: |
| None |
| |
| Global Stores/Buffers/Pointers Needed: |
| None |
| |
| Outputs: |
| var_out = number of left shifts need to normalize var1 (Word16) |
| |
| Pointers and Buffers Modified: |
| None |
| |
| Local Stores Modified: |
| None |
| |
| Global Stores Modified: |
| None |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| This function produces the number of left shifts needed to normalize the 16 |
| bit variable var1 for positive values on the interval with minimum of 0x4000 |
| and maximum of 0x7fff, and for negative values on the interval with minimum |
| of 0x8000 and maximum of 0xc000. Note that when var1 is zero, the resulting |
| output var_out is set to zero. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| [1] basicop2.c, ETS Version 2.0.0, February 8, 1999 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| Word16 norm_s (Word16 var1) |
| { |
| Word16 var_out; |
| |
| if (var1 == 0) |
| { |
| var_out = 0; |
| } |
| else |
| { |
| if (var1 == (Word16) 0xffff) |
| { |
| var_out = 15; |
| } |
| else |
| { |
| if (var1 < 0) |
| { |
| var1 = ~var1; |
| } |
| for (var_out = 0; var1 < 0x4000; var_out++) |
| { |
| var1 <<= 1; |
| } |
| } |
| } |
| |
| #if (WMOPS) |
| multiCounter[currCounter].norm_s++; |
| #endif |
| return (var_out); |
| } |
| |
| ------------------------------------------------------------------------------ |
| RESOURCES USED |
| When the code is written for a specific target processor the |
| the resources used should be documented below. |
| |
| STACK USAGE: [stack count for this module] + [variable to represent |
| stack usage for each subroutine called] |
| |
| where: [stack usage variable] = stack usage for [subroutine |
| name] (see [filename].ext) |
| |
| DATA MEMORY USED: x words |
| |
| PROGRAM MEMORY USED: x words |
| |
| CLOCK CYCLES: [cycle count equation for this module] + [variable |
| used to represent cycle count for each subroutine |
| called] |
| |
| where: [cycle count variable] = cycle count for [subroutine |
| name] (see [filename].ext) |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; 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 |
| ; Function Prototype declaration |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL STORE/BUFFER/POINTER DEFINITIONS |
| ; Variable declaration - defined here and used outside this module |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; EXTERNAL FUNCTION REFERENCES |
| ; Declare functions defined elsewhere and referenced in this module |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES |
| ; Declare variables used in this module but defined elsewhere |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; FUNCTION CODE |
| ----------------------------------------------------------------------------*/ |
| #if !( defined(PV_ARM_V5) || defined(PV_ARM_GCC_V5) ) |
| |
| Word16 norm_s(Word16 var1) |
| { |
| /*---------------------------------------------------------------------------- |
| ; Define all local variables |
| ----------------------------------------------------------------------------*/ |
| |
| Word16 var_out = 0; |
| |
| /*---------------------------------------------------------------------------- |
| ; Function body here |
| ----------------------------------------------------------------------------*/ |
| |
| if (var1) |
| { |
| Word16 y = var1 - (var1 < 0); |
| var1 = y ^(y >> 15); |
| |
| while (!(0x4000 & var1)) |
| { |
| var_out++; |
| if ((0x2000 & var1)) |
| { |
| break; |
| } |
| var_out++; |
| if ((0x1000 & var1)) |
| { |
| break; |
| } |
| var_out++; |
| if ((0x0800 & var1)) |
| { |
| break; |
| } |
| var_out++; |
| var1 <<= 4; |
| } |
| } |
| |
| /*---------------------------------------------------------------------------- |
| ; Return nothing or data or data pointer |
| ----------------------------------------------------------------------------*/ |
| return (var_out); |
| } |
| |
| #endif |