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authorAndreas Huber <andih@google.com>2009-12-07 09:56:32 -0800
committerAndreas Huber <andih@google.com>2009-12-07 11:02:28 -0800
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tree028b1d81643bbb332464b42b50a0f79ba5359142 /media/libstagefright/codecs/aacdec/fwd_long_complex_rot.cpp
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Initial check in of stagefright software AAC decoder based on PV source code.
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+/* ------------------------------------------------------------------
+ * 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/fwd_long_complex_rot.c
+ Funtions: fwd_long_complex_rot
+
+------------------------------------------------------------------------------
+ REVISION HISTORY
+
+ Date: 10/18/2002
+ Description:
+ (1) Change the input arguments, no shifts information from
+ long_fft_rx4 is passed, only a single max is passed.
+ (2) Eliminate search for max, a fixed shift has replaced the
+ search for max with minimal loss of precision.
+ (3) Eliminated unused variables
+
+ Date: 10/28/2002
+ Description:
+ (1) Added comments per code review
+ (2) Eliminated hardly used condition on if-else (exp==0)
+
+ Description:
+
+ ------------------------------------------------------------------------------
+ INPUT AND OUTPUT DEFINITIONS
+
+ Inputs:
+
+ Data_in = Input vector (sized for long windows
+ TWICE_FWD_LONG_CX_ROT_LENGTH), with time domain samples
+ type Int32 *
+
+ Data_out = Output vector with a post-rotation by exp(-j(2pi/N)(k+1/8)),
+ (sized for long windows TWICE_FWD_LONG_CX_ROT_LENGTH)
+ type Int32 *
+
+ max = Input, carries the maximum value of the input vector
+ "Data_in"
+ type Int32
+
+
+ Local Stores/Buffers/Pointers Needed:
+ None
+
+ Global Stores/Buffers/Pointers Needed:
+ None
+
+ Outputs:
+ exp = shift factor to reflect signal scaling
+
+ Pointers and Buffers Modified:
+ Results are return in "Data_out"
+
+ Local Stores Modified:
+ None
+
+ Global Stores Modified:
+ None
+------------------------------------------------------------------------------
+ FUNCTION DESCRIPTION
+
+ fwd_long_complex_rot() performs the pre complex rotation for the MDCT
+ for the case of long windows. It also performs digit reverse ordering of
+ the first and second halves of the input vector "Data_in", as well as
+ reordering of the two half vectors (following radix-2 decomposition)
+ Word normalization is also done to ensure 16 by 16 bit multiplications.
+
+------------------------------------------------------------------------------
+ REQUIREMENTS
+
+ fwd_long_complex_rot() should execute a pre-rotation by
+ exp(-j(2pi/N)(k+1/8)), digit reverse ordering and normalization
+------------------------------------------------------------------------------
+ REFERENCES
+
+------------------------------------------------------------------------------
+ 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 "fwd_long_complex_rot.h"
+#include "digit_reversal_tables.h"
+#include "imdct_fxp.h"
+#include "pv_normalize.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
+----------------------------------------------------------------------------*/
+
+Int fwd_long_complex_rot(
+ Int32 *Data_in,
+ Int32 *Data_out,
+ Int32 max)
+{
+ Int i;
+ const Int32 *p_rotate;
+ Int32 temp_re;
+ Int32 temp_im;
+ Int32 *pData_in_ref1;
+ Int32 *pData_in_ref2;
+ Int32 exp_jw;
+ Int32 temp_re_32;
+ Int32 temp_im_32;
+
+ Int32 *pData_out_1;
+ Int32 *pData_out_2;
+ Int32 *pData_out_3;
+ Int32 *pData_out_4;
+
+ Int32 *pData_in_1;
+ Int32 *pData_in_2;
+
+ Int exp;
+
+ p_rotate = exp_rotation_N_2048;
+
+ pData_in_ref1 = Data_in;
+ pData_in_ref2 = &Data_in[TWICE_FWD_LONG_CX_ROT_LENGTH];
+
+ pData_out_1 = Data_out;
+ pData_out_2 = &Data_out[LONG_WINDOW_LENGTH_m_1];
+ pData_out_3 = &Data_out[LONG_WINDOW_LENGTH];
+ pData_out_4 = &Data_out[TWICE_LONG_WINDOW_LENGTH_m_1];
+
+ /*
+ * Data_out
+ * >>>> <<<<
+ * pData_out_3 pData_out_4
+ * | | | | |
+ * pData_out_1 pData_out_2
+ * >>>> <<<<
+ */
+
+
+ exp = 16 - pv_normalize(max);
+
+ if (exp < 0)
+ {
+ exp = 0;
+ }
+
+ /*
+ * Apply A/2^(diff) + B
+ */
+
+
+ pData_in_1 = pData_in_ref1;
+ pData_in_2 = pData_in_ref2;
+
+ for (i = FWD_LONG_CX_ROT_LENGTH; i != 0; i--)
+ {
+
+ /*
+ * cos_n + j*sin_n == exp(j(2pi/N)(k+1/8))
+ */
+
+ exp_jw = *p_rotate++;
+
+ /*
+ * Use auxiliary variables to avoid double accesses to memory.
+ * Data in is scaled to use only lower 16 bits.
+ */
+
+ temp_re = *(pData_in_1++) >> exp;
+ temp_im = *(pData_in_1++) >> exp;
+
+ /*
+ * Pre-rotation
+ */
+
+ temp_re_32 = (cmplx_mul32_by_16(temp_re, temp_im, exp_jw));
+ temp_im_32 = (cmplx_mul32_by_16(temp_im, -temp_re, exp_jw));
+
+ *(pData_out_1++) = - temp_re_32;
+ *(pData_out_2--) = temp_im_32;
+ *(pData_out_3++) = - temp_im_32;
+ *(pData_out_4--) = temp_re_32;
+
+ /*
+ * Pointer increment to jump over imag (1 & 4) or real parts
+ * (2 & 3)
+ */
+ pData_out_1++;
+ pData_out_2--;
+ pData_out_3++;
+ pData_out_4--;
+
+ /*
+ * Repeat procedure for odd index at the output
+ */
+
+ exp_jw = *p_rotate++;
+
+ temp_re = *(pData_in_2++) >> exp;
+ temp_im = *(pData_in_2++) >> exp;
+
+ temp_re_32 = (cmplx_mul32_by_16(temp_re, temp_im, exp_jw));
+ temp_im_32 = (cmplx_mul32_by_16(temp_im, -temp_re, exp_jw));
+
+ *(pData_out_1++) = - temp_re_32;
+ *(pData_out_2--) = temp_im_32;
+ *(pData_out_3++) = - temp_im_32;
+ *(pData_out_4--) = temp_re_32;
+
+ pData_out_1++;
+ pData_out_2--;
+ pData_out_3++;
+ pData_out_4--;
+
+ }
+
+ return (exp + 1);
+}