diff options
Diffstat (limited to 'media/libstagefright/codecs/aacdec/pv_sqrt.cpp')
| -rw-r--r-- | media/libstagefright/codecs/aacdec/pv_sqrt.cpp | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/aacdec/pv_sqrt.cpp b/media/libstagefright/codecs/aacdec/pv_sqrt.cpp new file mode 100644 index 0000000..065fa38 --- /dev/null +++ b/media/libstagefright/codecs/aacdec/pv_sqrt.cpp @@ -0,0 +1,218 @@ +/* ------------------------------------------------------------------ + * 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. + * ------------------------------------------------------------------- + */ +/* + + Filename: pv_sqrt.c + +------------------------------------------------------------------------------ + REVISION HISTORY + + + Who: Date: MM/DD/YYYY + Description: + +------------------------------------------------------------------------------ + INPUT AND OUTPUT DEFINITIONS + + Int32 x 32-bit integer + + Int32 y 32-bit integer + + +------------------------------------------------------------------------------ + FUNCTION DESCRIPTION + + Implement root squared of a number + +------------------------------------------------------------------------------ + REQUIREMENTS + + +------------------------------------------------------------------------------ + REFERENCES + +------------------------------------------------------------------------------ + PSEUDO-CODE + +------------------------------------------------------------------------------ +*/ + + +/*---------------------------------------------------------------------------- +; INCLUDES +----------------------------------------------------------------------------*/ + +#ifdef AAC_PLUS + + +#include "pv_audio_type_defs.h" + +#include "fxp_mul32.h" +#include "pv_sqrt.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 +----------------------------------------------------------------------------*/ +#define R_SHIFT 28 +#define Q_fmt(x) (Int32)(x*((Int32)1<<R_SHIFT) + (x>=0?0.5F:-0.5F)) + + +const Int32 sqrt_table[9] = +{ + Q_fmt(-0.13829740941110F), Q_fmt(0.95383399963991F), + Q_fmt(-2.92784603873353F), Q_fmt(5.27429191920042F), + Q_fmt(-6.20272445821478F), Q_fmt(5.04717433019620F), + Q_fmt(-3.03362807640415F), Q_fmt(1.86178814410910F), + Q_fmt(0.16540758699193F) +}; + +/*---------------------------------------------------------------------------- +; 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 +----------------------------------------------------------------------------*/ + + +void pv_sqrt(Int32 man, Int32 exp, Root_sq *result, Int32 *sqrt_cache) +{ + + Int32 y; + Int32 xx; + Int32 nn; + Int32 i; + const Int32 *pt_table = sqrt_table; + + + if (sqrt_cache[0] == man && sqrt_cache[1] == exp) + { + result->root = sqrt_cache[2]; + result->shift_factor = (Int16)sqrt_cache[3]; + } + else + { + + sqrt_cache[0] = man; + sqrt_cache[1] = exp; + + + if (man > 0) + { + xx = man; + if (man >= Q_fmt(1.0f)) + { + nn = exp + 1; + while ((xx >>= 1) > Q_fmt(1.0f)) + { + nn++; + } + } + else if (man < Q_fmt(0.5f)) + { + nn = exp - 1; + while ((xx <<= 1) < Q_fmt(0.5f)) + { + nn--; + } + } + else + { + nn = exp; + } + + + y = fxp_mul32_Q28(*(pt_table++), xx); + + for (i = 3; i != 0; i--) + { + y += *(pt_table++); + y = fxp_mul32_Q28(y, xx); + y += *(pt_table++); + y = fxp_mul32_Q28(y, xx); + } + y += *(pt_table++); + y = fxp_mul32_Q28(y, xx) + *(pt_table++); + + if (nn >= 0) + { + if (nn&1) + { + y = fxp_mul32_Q29(y, Q_fmt(1.41421356237310F)); + result->shift_factor = (nn >> 1) - 28; + } + else + { + result->shift_factor = (nn >> 1) - 29; + } + } + else + { + if (nn&1) + { + y = fxp_mul32_Q28(y, Q_fmt(0.70710678118655F)); + } + + result->shift_factor = -((-nn) >> 1) - 29; + } + + result->root = y; + + } + else + { + result->root = 0; + result->shift_factor = 0; + } + + } + + sqrt_cache[2] = result->root; + sqrt_cache[3] = result->shift_factor; + +} + + +#endif + + |