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dbrochart |
######################################################################
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#### ####
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#### select.py ####
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#### ####
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#### This file is part of the turbo decoder IP core project ####
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#### http://www.opencores.org/projects/turbocodes/ ####
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#### ####
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#### Author(s): ####
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#### - David Brochart(dbrochart@opencores.org) ####
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#### ####
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#### All additional information is available in the README.txt ####
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#### file. ####
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#### ####
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######################################################################
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#### ####
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#### Copyright (C) 2005 Authors ####
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#### ####
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#### This source file may be used and distributed without ####
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#### restriction provided that this copyright statement is not ####
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#### removed from the file and that any derivative work contains ####
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#### the original copyright notice and the associated disclaimer. ####
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#### ####
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#### This source file is free software; you can redistribute it ####
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#### and/or modify it under the terms of the GNU Lesser General ####
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#### Public License as published by the Free Software Foundation; ####
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#### either version 2.1 of the License, or (at your option) any ####
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#### later version. ####
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#### ####
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#### This source is distributed in the hope that it will be ####
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#### useful, but WITHOUT ANY WARRANTY; without even the implied ####
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#### warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ####
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#### PURPOSE. See the GNU Lesser General Public License for more ####
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#### details. ####
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#### ####
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#### You should have received a copy of the GNU Lesser General ####
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#### Public License along with this source; if not, download it ####
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#### from http://www.opencores.org/lgpl.shtml ####
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#### ####
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######################################################################
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from misc import min4, cod2, mux4, min8, cod3
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from myhdl import Signal, instances
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def accDistSel(accDist, accDistCod, accDistOut, q = 8):
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""" Accumulated distance selection (one out of four, per state)
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accDist -- in : array of 32 (q+1)-bit accumulated distances
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accDistCod -- out : array of 8 2-bit selection signals
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accDistOut -- out : array of 8 (q+1)-bit selected accumulated distances
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"""
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min4_i = [None for i in range(8)]
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cod2_i = [None for i in range(8)]
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mux4_i = [None for i in range(8)]
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comp = [Signal(bool(0)) for i in range(24)]
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from2to = [0, 25, 6, 31, 8, 17, 14, 23, 20, 13, 18, 11, 28, 5, 26, 3, 4, 29, 2, 27, 12, 21, 10, 19, 16, 9, 22, 15, 24, 1, 30, 7]
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for i in range(8):
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min4_i[i] = min4(accDist[from2to[4*i]], accDist[from2to[4*i+1]], accDist[from2to[4*i+2]], accDist[from2to[4*i+3]], comp[3*i], comp[3*i+1], comp[3*i+2], q)
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for i in range(8):
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cod2_i[i] = cod2(comp[3*i], comp[3*i+1], comp[3*i+2], accDistCod[i])
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for i in range(8):
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mux4_i[i] = mux4(accDist[from2to[4*i]], accDist[from2to[4*i+1]], accDist[from2to[4*i+2]], accDist[from2to[4*i+3]], accDistCod[i], accDistOut[i])
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return min4_i, cod2_i, mux4_i
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def stateSel(stateDist, selState, q = 8):
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""" State selection (one out of eight).
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q -- accumulated distance width
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stateDist -- in : state accumulated distance
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selState -- out : selected state code
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"""
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tmp = [Signal(bool(0)) for i in range(7)]
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min8_i0 = min8(stateDist, tmp, q)
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cod3_i0 = cod3(tmp, selState)
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return min8_i0, cod3_i0
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