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// Chuck Benz, Hollis, NH Copyright (c)2002
//
// The information and description contained herein is the
// property of Chuck Benz.
//
// Permission is granted for any reuse of this information
// and description as long as this copyright notice is
// preserved. Modifications may be made as long as this
// notice is preserved.
// per Widmer and Franaszek
module decode_8b10b (datain, dispin, dataout, dispout, code_err, disp_err) ;
input [9:0] datain ;
input dispin ;
output [8:0] dataout ;
output dispout ;
output code_err ;
output disp_err ;
wire ai = datain[0] ;
wire bi = datain[1] ;
wire ci = datain[2] ;
wire di = datain[3] ;
wire ei = datain[4] ;
wire ii = datain[5] ;
wire fi = datain[6] ;
wire gi = datain[7] ;
wire hi = datain[8] ;
wire ji = datain[9] ;
wire aeqb = (ai & bi) | (!ai & !bi) ;
wire ceqd = (ci & di) | (!ci & !di) ;
wire p22 = (ai & bi & !ci & !di) |
(ci & di & !ai & !bi) |
( !aeqb & !ceqd) ;
wire p13 = ( !aeqb & !ci & !di) |
( !ceqd & !ai & !bi) ;
wire p31 = ( !aeqb & ci & di) |
( !ceqd & ai & bi) ;
wire p40 = ai & bi & ci & di ;
wire p04 = !ai & !bi & !ci & !di ;
wire disp6a = p31 | (p22 & dispin) ; // pos disp if p22 and was pos, or p31.
wire disp6a2 = p31 & dispin ; // disp is ++ after 4 bits
wire disp6a0 = p13 & ! dispin ; // -- disp after 4 bits
wire disp6b = (((ei & ii & ! disp6a0) | (disp6a & (ei | ii)) | disp6a2 |
(ei & ii & di)) & (ei | ii | di)) ;
// The 5B/6B decoding special cases where ABCDE != abcde
wire p22bceeqi = p22 & bi & ci & (ei == ii) ;
wire p22bncneeqi = p22 & !bi & !ci & (ei == ii) ;
wire p13in = p13 & !ii ;
wire p31i = p31 & ii ;
wire p13dei = p13 & di & ei & ii ;
wire p22aceeqi = p22 & ai & ci & (ei == ii) ;
wire p22ancneeqi = p22 & !ai & !ci & (ei == ii) ;
wire p13en = p13 & !ei ;
wire anbnenin = !ai & !bi & !ei & !ii ;
wire abei = ai & bi & ei & ii ;
wire cdei = ci & di & ei & ii ;
wire cndnenin = !ci & !di & !ei & !ii ;
// non-zero disparity cases:
wire p22enin = p22 & !ei & !ii ;
wire p22ei = p22 & ei & ii ;
//wire p13in = p12 & !ii ;
//wire p31i = p31 & ii ;
wire p31dnenin = p31 & !di & !ei & !ii ;
//wire p13dei = p13 & di & ei & ii ;
wire p31e = p31 & ei ;
wire compa = p22bncneeqi | p31i | p13dei | p22ancneeqi |
p13en | abei | cndnenin ;
wire compb = p22bceeqi | p31i | p13dei | p22aceeqi |
p13en | abei | cndnenin ;
wire compc = p22bceeqi | p31i | p13dei | p22ancneeqi |
p13en | anbnenin | cndnenin ;
wire compd = p22bncneeqi | p31i | p13dei | p22aceeqi |
p13en | abei | cndnenin ;
wire compe = p22bncneeqi | p13in | p13dei | p22ancneeqi |
p13en | anbnenin | cndnenin ;
wire ao = ai ^ compa ;
wire bo = bi ^ compb ;
wire co = ci ^ compc ;
wire do = di ^ compd ;
wire eo = ei ^ compe ;
wire feqg = (fi & gi) | (!fi & !gi) ;
wire heqj = (hi & ji) | (!hi & !ji) ;
wire fghj22 = (fi & gi & !hi & !ji) |
(!fi & !gi & hi & ji) |
( !feqg & !heqj) ;
wire fghjp13 = ( !feqg & !hi & !ji) |
( !heqj & !fi & !gi) ;
wire fghjp31 = ( (!feqg) & hi & ji) |
( !heqj & fi & gi) ;
wire dispout = (fghjp31 | (disp6b & fghj22) | (hi & ji)) & (hi | ji) ;
wire ko = ( (ci & di & ei & ii) | ( !ci & !di & !ei & !ii) |
(p13 & !ei & ii & gi & hi & ji) |
(p31 & ei & !ii & !gi & !hi & !ji)) ;
wire alt7 = (fi & !gi & !hi & // 1000 cases, where disp6b is 1
((dispin & ci & di & !ei & !ii) | ko |
(dispin & !ci & di & !ei & !ii))) |
(!fi & gi & hi & // 0111 cases, where disp6b is 0
(( !dispin & !ci & !di & ei & ii) | ko |
( !dispin & ci & !di & ei & ii))) ;
wire k28 = (ci & di & ei & ii) | ! (ci | di | ei | ii) ;
// k28 with positive disp into fghi - .1, .2, .5, and .6 special cases
wire k28p = ! (ci | di | ei | ii) ;
wire fo = (ji & !fi & (hi | !gi | k28p)) |
(fi & !ji & (!hi | gi | !k28p)) |
(k28p & gi & hi) |
(!k28p & !gi & !hi) ;
wire go = (ji & !fi & (hi | !gi | !k28p)) |
(fi & !ji & (!hi | gi |k28p)) |
(!k28p & gi & hi) |
(k28p & !gi & !hi) ;
wire ho = ((ji ^ hi) & ! ((!fi & gi & !hi & ji & !k28p) | (!fi & gi & hi & !ji & k28p) |
(fi & !gi & !hi & ji & !k28p) | (fi & !gi & hi & !ji & k28p))) |
(!fi & gi & hi & ji) | (fi & !gi & !hi & !ji) ;
wire disp6p = (p31 & (ei | ii)) | (p22 & ei & ii) ;
wire disp6n = (p13 & ! (ei & ii)) | (p22 & !ei & !ii) ;
wire disp4p = fghjp31 ;
wire disp4n = fghjp13 ;
assign code_err = p40 | p04 | (fi & gi & hi & ji) | (!fi & !gi & !hi & !ji) |
(p13 & !ei & !ii) | (p31 & ei & ii) |
(ei & ii & fi & gi & hi) | (!ei & !ii & !fi & !gi & !hi) |
(ei & !ii & gi & hi & ji) | (!ei & ii & !gi & !hi & !ji) |
(!p31 & ei & !ii & !gi & !hi & !ji) |
(!p13 & !ei & ii & gi & hi & ji) |
(((ei & ii & !gi & !hi & !ji) |
(!ei & !ii & gi & hi & ji)) &
! ((ci & di & ei) | (!ci & !di & !ei))) |
(disp6p & disp4p) | (disp6n & disp4n) |
(ai & bi & ci & !ei & !ii & ((!fi & !gi) | fghjp13)) |
(!ai & !bi & !ci & ei & ii & ((fi & gi) | fghjp31)) |
(fi & gi & !hi & !ji & disp6p) |
(!fi & !gi & hi & ji & disp6n) |
(ci & di & ei & ii & !fi & !gi & !hi) |
(!ci & !di & !ei & !ii & fi & gi & hi) ;
assign dataout = {ko, ho, go, fo, eo, do, co, bo, ao} ;
// my disp err fires for any legal codes that violate disparity, may fire for illegal codes
assign disp_err = ((dispin & disp6p) | (disp6n & !dispin) |
(dispin & !disp6n & fi & gi) |
(dispin & ai & bi & ci) |
(dispin & !disp6n & disp4p) |
(!dispin & !disp6p & !fi & !gi) |
(!dispin & !ai & !bi & !ci) |
(!dispin & !disp6p & disp4n) |
(disp6p & disp4p) | (disp6n & disp4n)) ;
endmodule
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