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Diffstat (limited to 'opencore/codecs_v2/audio/gsm_amr/amr_nb/common/src/shr.cpp')
| -rw-r--r-- | opencore/codecs_v2/audio/gsm_amr/amr_nb/common/src/shr.cpp | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/opencore/codecs_v2/audio/gsm_amr/amr_nb/common/src/shr.cpp b/opencore/codecs_v2/audio/gsm_amr/amr_nb/common/src/shr.cpp new file mode 100644 index 0000000..a0fbd35 --- /dev/null +++ b/opencore/codecs_v2/audio/gsm_amr/amr_nb/common/src/shr.cpp @@ -0,0 +1,201 @@ +/* ------------------------------------------------------------------ + * 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: shr.cpp + +------------------------------------------------------------------------------ + MODULE DESCRIPTION + Shift right function with overflow control +------------------------------------------------------------------------------ +*/ + +/*---------------------------------------------------------------------------- +; 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: shr +------------------------------------------------------------------------------ + INPUT AND OUTPUT DEFINITIONS + + Inputs: + var1 = 16 bit short signed integer (Word16) whose value falls in + the range : 0xffff 8000 <= var1 <= 0x0000 7fff. + + var2 = 16 bit short signed integer (Word16) whose value falls in + the range : 0xffff 8000 <= var2 <= 0x0000 7fff. + + pOverflow = pointer to overflow (Flag) + + Outputs: + pOverflow -> 1 if the shift operation resulted in overflow + + Returns: + product = Shifted result limited to 16 bits (Word16) + + Global Variables Used: + None + + Local Variables Needed: + None + +------------------------------------------------------------------------------ + FUNCTION DESCRIPTION + + This function arithmetically shifts the 16 bit input var1 right var2 positions + with sign extension. If var2 is negative, arithmetically shift var1 left by + -var2 with sign extension. Saturate the result in case of underflows or + overflows. + +------------------------------------------------------------------------------ + REQUIREMENTS + None +------------------------------------------------------------------------------ + REFERENCES + + [1] shr() function in basic_op2.c, UMTS GSM AMR speech codec, R99 - + Version 3.2.0, March 2, 2001 + +------------------------------------------------------------------------------ + PSEUDO-CODE + +Word16 shr_std (Word16 var1, Word16 var2) +{ + Word16 var_out; + + if (var2 < 0) + { + if (var2 < -16) + var2 = -16; + var_out = shl_std (var1, -var2); +#if (WMOPS) + mult_stdiCounter[currCounter].shl_std--; +#endif + } + else + { + if (var2 >= 15) + { + var_out = (var1 < 0) ? -1 : 0; + } + else + { + if (var1 < 0) + { + var_out = ~((~var1) >> var2); + } + else + { + var_out = var1 >> var2; + } + } + } + +#if (WMOPS) + mult_stdiCounter[currCounter].shr_std++; +#endif + return (var_out); +} +------------------------------------------------------------------------------ + CAUTION [optional] + [State any special notes, constraints or cautions for users of this function] + +------------------------------------------------------------------------------ +*/ + +/*---------------------------------------------------------------------------- +; FUNCTION CODE +----------------------------------------------------------------------------*/ +OSCL_EXPORT_REF Word16 shr(register Word16 var1, register Word16 var2, Flag *pOverflow) +{ + register Word16 result; + + if (var2 != 0) + { + if (var2 > 0) + { + if (var2 > 15) + { + var2 = 15; + } + + result = var1 >> var2; + + } + else + { + var2 = -var2; /* Shift right negative is equivalent */ + + if (var2 > 15) + { + var2 = 15; + } + + result = (var1 << var2); + if ((result >> var2) != var1) + { + *pOverflow = 1; + result = ((var1 > 0) ? MAX_16 : MIN_16); + } + } + + } + else + { + result = var1; + } + + return (result); +} + |