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Diffstat (limited to 'media/openmax_dl/dl/sp/src/omxSP_FFTInit_R_S32.c')
-rw-r--r-- | media/openmax_dl/dl/sp/src/omxSP_FFTInit_R_S32.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/media/openmax_dl/dl/sp/src/omxSP_FFTInit_R_S32.c b/media/openmax_dl/dl/sp/src/omxSP_FFTInit_R_S32.c new file mode 100644 index 000000000..337f2a20b --- /dev/null +++ b/media/openmax_dl/dl/sp/src/omxSP_FFTInit_R_S32.c @@ -0,0 +1,261 @@ +/* + * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE file in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + * + * This file was originally licensed as follows. It has been + * relicensed with permission from the copyright holders. + */ + +/** + * + * File Name: omxSP_FFTInit_R_S32.c + * OpenMAX DL: v1.0.2 + * Last Modified Revision: 7777 + * Last Modified Date: Thu, 27 Sep 2007 + * + * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved. + * + * + * Description: + * Initialize the real forward-FFT specification information struct. + */ + +#include "dl/api/armOMX.h" +#include "dl/api/omxtypes.h" +#include "dl/sp/api/armSP.h" +#include "dl/sp/api/omxSP.h" + + + +/** + * Function: omxSP_FFTInit_R_S32 + * + * Description: + * Initialize the real forward-FFT specification information struct. + * + * Remarks: + * This function is used to initialize the specification structures + * for functions <ippsFFTFwd_RToCCS_S32_Sfs> and + * <ippsFFTInv_CCSToR_S32_Sfs>. Memory for *pFFTSpec must be + * allocated prior to calling this function. The number of bytes + * required for *pFFTSpec can be determined using + * <FFTGetBufSize_R_S32>. + * + * Parameters: + * [in] order base-2 logarithm of the desired block length; + * valid in the range [0,12]. + * [out] pFFTFwdSpec pointer to the initialized specification structure. + * + * Return Value: + * Standard omxError result. See enumeration for possible result codes. + * + */ +OMXResult omxSP_FFTInit_R_S32( + OMXFFTSpec_R_S32* pFFTSpec, + OMX_INT order +) +{ + OMX_INT i,j; + OMX_SC32 *pTwiddle,*pTwiddle1,*pTwiddle2,*pTwiddle3,*pTwiddle4; + OMX_S32 *pBuf; + OMX_U16 *pBitRev; + OMX_U32 pTmp; + OMX_INT Nby2,N,M,diff, step; + OMX_S32 x,y,xNeg; + ARMsFFTSpec_R_SC32 *pFFTStruct = 0; + + + pFFTStruct = (ARMsFFTSpec_R_SC32 *) pFFTSpec; + + /* if order zero no init is needed */ + if (order == 0) + { + pFFTStruct->N = 1; + pFFTStruct->pTwiddle = NULL; + pFFTStruct->pBuf = (OMX_S32 *) + (sizeof(ARMsFFTSpec_R_SC32) + (OMX_S8*) pFFTSpec); + + return OMX_Sts_NoErr; + } + + /* Do the initializations */ + Nby2 = 1 << (order - 1); + N = Nby2 << 1; + + + + pBitRev = NULL ; /* optimized implementations don't use bitreversal */ + + pTwiddle = (OMX_SC32 *) + (sizeof(ARMsFFTSpec_R_SC32) + (OMX_S8*) pFFTSpec); + + /* Align to 32 byte boundary */ + pTmp = ((OMX_U32)pTwiddle)&31; /* (OMX_U32)pTwiddle % 32 */ + if(pTmp != 0) + pTwiddle = (OMX_SC32*) ((OMX_S8*)pTwiddle + (32-pTmp)); + + pBuf = (OMX_S32*) + (sizeof(OMX_SC32) * (5*N/8) + (OMX_S8*) pTwiddle); + + /* Align to 32 byte boundary */ + pTmp = ((OMX_U32)pBuf)&31; /* (OMX_U32)pBuf % 32 */ + if(pTmp != 0) + pBuf = (OMX_S32*) ((OMX_S8*)pBuf + (32-pTmp)); + + + + + /* + * Filling Twiddle factors : exp^(-j*2*PI*k/ (N/2) ) ; k=0,1,2,...,3/4(N/2) + * N/2 point complex FFT is used to compute N point real FFT + * The original twiddle table "armSP_FFT_S32TwiddleTable" is of size (MaxSize/8 + 1) + * Rest of the values i.e., upto MaxSize are calculated using the symmetries of sin and cos + * The max size of the twiddle table needed is 3/4(N/2) for a radix-4 stage + * + * W = (-2 * PI) / N + * N = 1 << order + * W = -PI >> (order - 1) + */ + + M = Nby2>>3; + diff = 12 - (order-1); + step = 1<<diff; /* step into the twiddle table for the current order */ + + x = armSP_FFT_S32TwiddleTable[0]; + y = armSP_FFT_S32TwiddleTable[1]; + xNeg = 0x7FFFFFFF; + + if((order-1) >=3) + { + /* i = 0 case */ + pTwiddle[0].Re = x; + pTwiddle[0].Im = y; + pTwiddle[2*M].Re = -y; + pTwiddle[2*M].Im = xNeg; + pTwiddle[4*M].Re = xNeg; + pTwiddle[4*M].Im = y; + + + for (i=1; i<=M; i++) + { + j = i*step; + + x = armSP_FFT_S32TwiddleTable[2*j]; + y = armSP_FFT_S32TwiddleTable[2*j+1]; + + pTwiddle[i].Re = x; + pTwiddle[i].Im = y; + pTwiddle[2*M-i].Re = -y; + pTwiddle[2*M-i].Im = -x; + pTwiddle[2*M+i].Re = y; + pTwiddle[2*M+i].Im = -x; + pTwiddle[4*M-i].Re = -x; + pTwiddle[4*M-i].Im = y; + pTwiddle[4*M+i].Re = -x; + pTwiddle[4*M+i].Im = -y; + pTwiddle[6*M-i].Re = y; + pTwiddle[6*M-i].Im = x; + } + + + } + else + { + if ((order-1) == 2) + { + pTwiddle[0].Re = x; + pTwiddle[0].Im = y; + pTwiddle[1].Re = -y; + pTwiddle[1].Im = xNeg; + pTwiddle[2].Re = xNeg; + pTwiddle[2].Im = y; + + } + if ((order-1) == 1) + { + pTwiddle[0].Re = x; + pTwiddle[0].Im = y; + + } + + + } + + + /* + * Now fill the last N/4 values : exp^(-j*2*PI*k/N) ; k=1,3,5,...,N/2-1 + * These are used for the final twiddle fix-up for converting complex to real FFT + */ + + M = N>>3; + diff = 12 - order; + step = 1<<diff; + + pTwiddle1 = pTwiddle + 3*N/8; + pTwiddle4 = pTwiddle1 + (N/4-1); + pTwiddle3 = pTwiddle1 + N/8; + pTwiddle2 = pTwiddle1 + (N/8-1); + + x = armSP_FFT_S32TwiddleTable[0]; + y = armSP_FFT_S32TwiddleTable[1]; + xNeg = 0x7FFFFFFF; + + if((order) >=3) + { + + + for (i=1; i<=M; i+=2 ) + { + j = i*step; + + x = armSP_FFT_S32TwiddleTable[2*j]; + y = armSP_FFT_S32TwiddleTable[2*j+1]; + + pTwiddle1[0].Re = x; + pTwiddle1[0].Im = y; + pTwiddle1 += 1; + pTwiddle2[0].Re = -y; + pTwiddle2[0].Im = -x; + pTwiddle2 -= 1; + pTwiddle3[0].Re = y; + pTwiddle3[0].Im = -x; + pTwiddle3 += 1; + pTwiddle4[0].Re = -x; + pTwiddle4[0].Im = y; + pTwiddle4 -= 1; + + } + + + } + else + { + if (order == 2) + { + + pTwiddle1[0].Re = -y; + pTwiddle1[0].Im = xNeg; + + } + + + } + + + /* Update the structure */ + pFFTStruct->N = N; + pFFTStruct->pTwiddle = pTwiddle; + pFFTStruct->pBitRev = pBitRev; + pFFTStruct->pBuf = pBuf; + + return OMX_Sts_NoErr; +} +/***************************************************************************** + * END OF FILE + *****************************************************************************/ + |