62 lines
1.5 KiB
C++
62 lines
1.5 KiB
C++
/*
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* Project 25 IMBE Encoder/Decoder Fixed-Point implementation
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* Developed by Pavel Yazev E-mail: pyazev@gmail.com
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* Version 1.0 (c) Copyright 2009
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*
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* This is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* The software is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this; see the file COPYING. If not, write to the Free
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* Software Foundation, Inc., 51 Franklin Street, Boston, MA
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* 02110-1301, USA.
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*/
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#include "typedef.h"
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#include "basic_op.h"
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static UWord32 seed = 1;
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//-----------------------------------------------------------------------------
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// PURPOSE:
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// Generate pseudo-random numbers in range -1...1
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//
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//
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// INPUT:
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// None
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//
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// OUTPUT:
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// None
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//
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// RETURN:
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// Pseudo-random number in signed Q1.16 format
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//
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//-----------------------------------------------------------------------------
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Word16 rand_gen(void)
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{
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UWord32 hi, lo;
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lo = 16807 * (seed & 0xFFFF);
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hi = 16807 * (seed >> 16);
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lo += (Word32)(hi & 0x7FFF) << 16;
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lo += (hi >> 15);
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if(lo > 0x7FFFFFFF)
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lo -= 0x7FFFFFFF;
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seed = lo;
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return (Word16)lo;
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}
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