| /* |
| * 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_C_SC16.c |
| * OpenMAX DL: v1.0.2 |
| * Last Modified Revision: 15322 |
| * Last Modified Date: Wed, 15 Oct 2008 |
| * |
| * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved. |
| * |
| * |
| * Description: |
| * Initializes the specification structures required |
| */ |
| |
| #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_C_SC16 |
| * |
| * Description: |
| * These functions initialize the specification structures required for the |
| * complex FFT and IFFT functions. |
| * |
| * Remarks: |
| * Desired block length is specified as an input. The function is used to |
| * initialize the specification structures for functions <FFTFwd_CToC_SC16_Sfs> |
| * and <FFTInv_CToC_SC16_Sfs>. Memory for the specification structure *pFFTSpec |
| * must be allocated prior to calling this function. The space required for |
| * *pFFTSpec, in bytes, can be determined using <FFTGetBufSize_C_SC16>. |
| * |
| * Parameters: |
| * [in] order base-2 logarithm of the desired block length; |
| * valid in the range [0,12]. |
| * [out] pFFTSpec pointer to initialized specification structure. |
| * |
| * Return Value: |
| * Standard omxError result. See enumeration for possible result codes. |
| * |
| */ |
| |
| OMXResult omxSP_FFTInit_C_SC16( |
| OMXFFTSpec_C_SC16* pFFTSpec, |
| OMX_INT order |
| ) |
| { |
| OMX_INT i,j; |
| OMX_SC16 *pTwiddle, *pBuf; |
| OMX_U16 *pBitRev; |
| OMX_INT Nby2,N,M,diff,step; |
| OMX_U32 pTmp; |
| ARMsFFTSpec_SC16 *pFFTStruct = 0; |
| OMX_S16 x,y,xNeg; |
| OMX_S32 xS32,yS32; |
| |
| |
| pFFTStruct = (ARMsFFTSpec_SC16 *) pFFTSpec; |
| |
| /* if order zero no init is needed */ |
| if (order == 0) |
| { |
| pFFTStruct->N = 1; |
| return OMX_Sts_NoErr; |
| } |
| |
| /* Do the initializations */ |
| Nby2 = 1 << (order - 1); |
| N = Nby2 << 1; |
| M = N>>3; |
| |
| pBitRev = NULL ; |
| |
| pTwiddle = (OMX_SC16 *) |
| (sizeof(ARMsFFTSpec_SC16) + (OMX_S8*) pFFTSpec); |
| |
| /* Align to 32 byte boundary */ |
| pTmp = ((OMX_U32)pTwiddle)&31; /* (OMX_U32)pTwiddle % 32 */ |
| if(pTmp != 0) |
| pTwiddle = (OMX_SC16*) ((OMX_S8*)pTwiddle + (32-pTmp)); |
| |
| pBuf = (OMX_SC16 *) |
| (sizeof(OMX_SC16) * (3*N/4) + (OMX_S8*) pTwiddle); |
| |
| /* Align to 32 byte boundary */ |
| pTmp = ((OMX_U32)pBuf)&31; /* (OMX_U32)pBuf % 32 */ |
| if(pTmp != 0) |
| pBuf = (OMX_SC16*) ((OMX_S8*)pBuf + (32-pTmp)); |
| |
| |
| |
| /* |
| * Filling Twiddle factors : |
| * The original twiddle table "armSP_FFT_S16TwiddleTable" 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 3N/4 for a radix-4 stage |
| * |
| * W = (-2 * PI) / N |
| * N = 1 << order |
| * W = -PI >> (order - 1) |
| */ |
| |
| |
| |
| diff = 12 - order; |
| step = 1<<diff; /* step into the twiddle table for the current order */ |
| |
| xS32 = armSP_FFT_S32TwiddleTable[0]; |
| yS32 = armSP_FFT_S32TwiddleTable[1]; |
| x = (xS32+0x8000)>>16; |
| y = (yS32+0x8000)>>16; |
| |
| xNeg = 0x7FFF; |
| |
| if(order >=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; |
| |
| xS32 = armSP_FFT_S32TwiddleTable[2*j]; |
| yS32 = armSP_FFT_S32TwiddleTable[2*j+1]; |
| x = (xS32+0x8000)>>16; |
| y = (yS32+0x8000)>>16; |
| |
| 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 == 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) |
| { |
| pTwiddle[0].Re = x; |
| pTwiddle[0].Im = y; |
| |
| } |
| |
| |
| } |
| |
| |
| /* Update the structure */ |
| pFFTStruct->N = N; |
| pFFTStruct->pTwiddle = pTwiddle; |
| pFFTStruct->pBitRev = pBitRev; |
| pFFTStruct->pBuf = pBuf; |
| |
| return OMX_Sts_NoErr; |
| } |
| |
| /***************************************************************************** |
| * END OF FILE |
| *****************************************************************************/ |
| |