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dbrochart |
######################################################################
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#### ####
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#### acs.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 selec import accDistSel, stateSel
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from misc import opposite, delayer, mux8, mux4, sub
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from distances import distances, accDist
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from myhdl import Signal, instances, intbv
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def acs(clk, rst, a, b, y1, y2, z, selStateL, selDistL, selState, stateDist, weight, q = 8, l = 20, n = 4, r = 5):
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""" Add-Compare-Select top level.
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q -- accumulated distance width
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l -- first trellis length
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n -- received decoder signal width
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r -- extrinsic information width
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clk, rst -- in : clock and negative reset
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a, b, y1, y2 -- in : received decoder signals
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z -- in : extrinsic information
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selStateL -- in : selected state at t = L
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selDistL -- in : selected transition at selStateL
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selState -- out : selected state
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stateDist -- out : selected accumulated distances (per state)
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weight -- out : four weights sorted by transition code
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"""
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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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distance16 = [Signal(intbv(0, 0, 4*(2**(n-1))+(2**r))) for i in range(16)]
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accDist8 = [Signal(intbv(0, 0, 2**q)) for i in range(8)]
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accDist32 = [Signal(intbv(0, 0, 2**q)) for i in range(32)]
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accDistDel32 = [[Signal(intbv(0, 0, 2**q)) for i in range(4)] for j in range(8)]
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accDistDel4 = [Signal(intbv(0, 0, 2**q)) for i in range(4)]
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selAccDistL = Signal(intbv(0, 0, 2**q))
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delayer_i = [None for i in range(32)]
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distances_i0 = distances(a, b, y1, y2, z, distance16)
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accDist_i0 = accDist(clk, rst, accDist8, distance16, accDist32, q)
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for i in range(8):
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for j in range(4):
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delayer_i[i * 4 + j] = delayer(clk, rst, accDist32[from2to[i * 4 + j]], accDistDel32[i][j], l - 1, 0, 2**(q+1))
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mux8_i0 = mux8(accDistDel32[0], accDistDel32[1], accDistDel32[2], accDistDel32[3], accDistDel32[4], accDistDel32[5], accDistDel32[6], accDistDel32[7], selStateL, accDistDel4)
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mux4_i0 = mux4(accDistDel4[0], accDistDel4[1], accDistDel4[2], accDistDel4[3], selDistL, selAccDistL)
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sub_i0 = sub(accDistDel4[0], selAccDistL, weight[0])
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sub_i1 = sub(accDistDel4[1], selAccDistL, weight[1])
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sub_i2 = sub(accDistDel4[2], selAccDistL, weight[2])
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sub_i3 = sub(accDistDel4[3], selAccDistL, weight[3])
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accDistSel_i0 = accDistSel(accDist32, stateDist, accDist8, q)
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stateSel_i0 = stateSel(accDist8, selState, q)
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return distances_i0, accDist_i0, mux8_i0, mux4_i0, sub_i0, sub_i1, sub_i2, sub_i3, accDistSel_i0, stateSel_i0, delayer_i
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