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Diffstat (limited to 'media/libstagefright/codecs/aacdec/fft_rx4_long.cpp')
| -rw-r--r-- | media/libstagefright/codecs/aacdec/fft_rx4_long.cpp | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/aacdec/fft_rx4_long.cpp b/media/libstagefright/codecs/aacdec/fft_rx4_long.cpp new file mode 100644 index 0000000..c517e7e --- /dev/null +++ b/media/libstagefright/codecs/aacdec/fft_rx4_long.cpp @@ -0,0 +1,428 @@ +/* ------------------------------------------------------------------ + * 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. + * ------------------------------------------------------------------- + */ +/* + + Pathname: ./src/fft_rx4_long.c + Funtions: fft_rx4_long + +------------------------------------------------------------------------------ + REVISION HISTORY + + Description: + (1) Eliminated search for max in the main loop. + (2) Reduced precision on w_256rx4 from Q15 to Q10 + + Description: + (1) Created function fft_rx4_long_no_max to overcome LTP problem. + + Description: + (1) Modified shift so the accumulation growths faster than the + downshift, so now the input can be as high as 1.0 and saturation + will not occurre. The accumulation times the Q10 format will + never exceed 31 bits. This increases precision + (2) Eliminated unneeded data moves, used before for max search. + (3) Eliminated function fft_rx4_long_no_max. + + Description: + (1) Added comment to explain max search elimination and + Q format during multiplications + + Who: Date: + Description: + +------------------------------------------------------------------------------ + INPUT AND OUTPUT DEFINITIONS + + Inputs: + Data = Input complex vector, arranged in the following order: + real, imag, real, imag... + This is a complex vector whose elements (real and Imag) are + Int32. + type Int32 * + + peak_value = Input, peak value of the input vector + Output, peak value of the resulting vector + type Int32 * + + Local Stores/Buffers/Pointers Needed: + None + + Global Stores/Buffers/Pointers Needed: + None + + Outputs: + None + + Pointers and Buffers Modified: + calculation are done in-place and returned in Data + + Local Stores Modified: + None + + Global Stores Modified: + None + +------------------------------------------------------------------------------ + FUNCTION DESCRIPTION + + Fast Fourier Transform, radix 4 with Decimation in Frequency and block + floating point arithmetic. + The radix-4 FFT simply divides the FFT into four smaller FFTs. Each of + the smaller FFTs is then further divided into smaller ones and so on. + It consists of log 4 N stages and each stage consists of N/4 dragonflies. + + An FFT is nothing but a bundle of multiplications and summations which + may overflow during calculations. + + + This routine uses a scheme to test and scale the result output from + each FFT stage in order to fix the accumulation overflow. + + The Input Data should be in Q13 format to get the highest precision. + At the end of each dragonfly calculation, a test for possible bit growth + is made, if bit growth is possible the Data is scale down back to Q13. + +------------------------------------------------------------------------------ + REQUIREMENTS + + This function should provide a fixed point FFT for an input array + of size 256. + +------------------------------------------------------------------------------ + REFERENCES + + [1] Advance Digital Signal Processing, J. Proakis, C. Rader, F. Ling, + C. Nikias, Macmillan Pub. Co. + +------------------------------------------------------------------------------ + PSEUDO-CODE + + + MODIFY( x[] ) + RETURN( exponent ) + +------------------------------------------------------------------------------ + 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 "pv_audio_type_defs.h" +#include "fft_rx4.h" + +#include "fxp_mul32.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 VARIABLE DEFINITIONS +; Variable declaration - defined here and used outside this module +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; EXTERNAL FUNCTION REFERENCES +; Declare functions defined elsewhere and referenced in this module +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; EXTERNAL VARIABLES REFERENCES +; Declare variables used in this module but defined elsewhere +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES +; Declare variables used in this module but defined elsewhere +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; FUNCTION CODE +----------------------------------------------------------------------------*/ + + +void fft_rx4_long( + Int32 Data[], + Int32 *peak_value) + +{ + Int n1; + Int n2; + Int j; + Int k; + Int i; + + Int32 t1; + Int32 t2; + Int32 r1; + Int32 r2; + Int32 r3; + Int32 r4; + Int32 s1; + Int32 s2; + Int32 s3; + Int32 *pData1; + Int32 *pData2; + Int32 *pData3; + Int32 *pData4; + Int32 temp1; + Int32 temp2; + Int32 temp3; + Int32 temp4; + Int32 max; + + Int32 exp_jw1; + Int32 exp_jw2; + Int32 exp_jw3; + + + + const Int32 *pw = W_256rx4; + + n2 = FFT_RX4_LONG; + + for (k = FFT_RX4_LONG; k > 4; k >>= 2) + { + + n1 = n2; + n2 >>= 2; + + for (i = 0; i < FFT_RX4_LONG; i += n1) + { + pData1 = &Data[ i<<1]; + pData2 = pData1 + n1; + + temp1 = *pData1; + temp2 = *pData2; + + r1 = temp1 + temp2; + r2 = temp1 - temp2; + + pData3 = pData1 + (n1 >> 1); + pData4 = pData3 + n1; + temp3 = *pData3++; + temp4 = *pData4++; + + t1 = temp3 + temp4; + + *(pData1++) = (r1 + t1); + t2 = temp3 - temp4; + *(pData2++) = (r1 - t1); + + temp1 = *pData1; + temp2 = *pData2; + + s1 = temp1 + temp2; + temp3 = *pData3; + s2 = temp1 - temp2; + temp4 = *pData4; + *pData3-- = (s2 - t2); + *pData4-- = (s2 + t2); + + t1 = temp3 + temp4; + + *pData1 = (s1 + t1); + *pData2 = (s1 - t1); + + r1 = temp3 - temp4; + + *pData4 = (r2 - r1); + *pData3 = (r2 + r1); + + } /* i */ + + + + for (j = 1; j < n2; j++) + { + + exp_jw1 = (*pw++); + exp_jw2 = (*pw++); + exp_jw3 = (*pw++); + + + for (i = j; i < FFT_RX4_LONG; i += n1) + { + pData1 = &Data[ i<<1]; + pData2 = pData1 + n1; + + temp1 = *pData1; + temp2 = *pData2++; + + r1 = temp1 + temp2; + r2 = temp1 - temp2; + + pData3 = pData1 + (n1 >> 1); + pData4 = pData3 + n1; + temp3 = *pData3++; + temp4 = *pData4++; + + r3 = temp3 + temp4; + r4 = temp3 - temp4; + + *(pData1++) = (r1 + r3); + r1 = (r1 - r3) << 1; + + temp2 = *pData2; + temp1 = *pData1; + + s1 = temp1 + temp2; + s2 = temp1 - temp2; + s3 = (s2 + r4) << 1; + s2 = (s2 - r4) << 1; + + temp3 = *pData3; + temp4 = *pData4; + + t1 = temp3 + temp4; + t2 = temp3 - temp4; + + *pData1 = (s1 + t1); + s1 = (s1 - t1) << 1; + + *pData2-- = cmplx_mul32_by_16(s1, -r1, exp_jw2); + r3 = (r2 - t2) << 1; + *pData2 = cmplx_mul32_by_16(r1, s1, exp_jw2); + + r2 = (r2 + t2) << 1; + + *pData3-- = cmplx_mul32_by_16(s2, -r2, exp_jw1); + *pData3 = cmplx_mul32_by_16(r2, s2, exp_jw1); + + *pData4-- = cmplx_mul32_by_16(s3, -r3, exp_jw3); + *pData4 = cmplx_mul32_by_16(r3, s3, exp_jw3); + + } /* i */ + + } /* j */ + + } /* k */ + + + max = 0; + + pData1 = Data - 7; + + + for (i = ONE_FOURTH_FFT_RX4_LONG; i != 0 ; i--) + { + pData1 += 7; + pData2 = pData1 + 4; + + + temp1 = *pData1; + temp2 = *pData2++; + + r1 = temp1 + temp2; + r2 = temp1 - temp2; + + pData3 = pData1 + 2; + pData4 = pData1 + 6; + temp1 = *pData3++; + temp2 = *pData4++; + + t1 = temp1 + temp2; + t2 = temp1 - temp2; + + temp1 = (r1 + t1); + r1 = (r1 - t1); + *(pData1++) = temp1; + max |= (temp1 >> 31) ^ temp1; + + + + temp2 = *pData2; + temp1 = *pData1; + + s1 = temp1 + temp2; + s2 = temp1 - temp2; + + + temp1 = *pData3; + temp2 = *pData4; + + s3 = (s2 + t2); + s2 = (s2 - t2); + + t1 = temp1 + temp2; + t2 = temp1 - temp2; + + temp1 = (s1 + t1); + *pData1 = temp1; + temp2 = (s1 - t1); + + max |= (temp1 >> 31) ^ temp1; + *pData2-- = temp2; + max |= (temp2 >> 31) ^ temp2; + + *pData2 = r1; + max |= (r1 >> 31) ^ r1; + *pData3-- = s2; + max |= (s2 >> 31) ^ s2; + *pData4-- = s3; + max |= (s3 >> 31) ^ s3; + + temp1 = (r2 - t2); + *pData4 = temp1; + temp2 = (r2 + t2); + *pData3 = temp2; + max |= (temp1 >> 31) ^ temp1; + max |= (temp2 >> 31) ^ temp2; + + } /* i */ + + *peak_value = max; + + return ; + +} + |