test :- Strdata = [10,20,5,100,1,6,2,3],
    datagen(Strdata,Data),
    pipe(Data,Out),
    length(18),
    #write(Out).

        % Data Generator

datagen([],[]).
datagen([H|T],Out) :-
    Out = [H],
    @T = T, @datagen(T,Out).

        % Pipeline Merge Sorter

pipe(I0,Out) :-
    I1 = [], I2 = [], Out = [],
    proc_start(I0,I1, 2,1),
    proc_start(I1,I2, 4,2),
    proc_start(I2,Out,8,4).

    % Processor Unit

proc_start(I,O,P,PP) :-
    X = [], Y = [], Z = [], T = 1,
    #proc(I,O,X,Y,Z,T,P,PP).

proc(I,O,X,Y,Z,T,P,PP) :- X=[],Y=[],I=[],!,
    @X=X, @Y=Y, @Z=Z, @O=[], @T=1.
proc(I,O,X,Y,Z,T,P,PP) :-
     load(I,O,X,Y,Yn,Z,Zn,T,P,PP),
    merge(I,O,X,Y,Yn,Z,Zn,T,P,PP).

load(I,O,X,Y,Yn,Z,Zn,T,P,PP) :- T=<PP, !,
    append(Z,I,Zn), @Z=Zn, Yn=Y,
    @T=T+1.
load(I,O,X,Y,Yn,Z,Zn,T,P,PP) :- 
    append(Y,I,Yn), @Z=[],
    (if T<P then @T=T+1 else @T=1).

merge(I,O,X,Y,Yn,Z,Zn,T,P,PP) :-X=[],Yn=[],!,
    @O=[], @Y=Yn,
    (if T=PP then @X=Zn else @X=X).
merge(I,O,X,Y,Yn,Z,Zn,T,P,PP) :- X=[A|L],Yn=[],!,
    @O=[A], @Y=Yn,
    (if T=PP then @X=Zn else @X=L).
merge(I,O,X,Y,Yn,Z,Zn,T,P,PP) :-X=[],Yn=[B|N],!,
    @O=[B], @Y=N,
    (if T=PP then @X=Zn else @X=X).
merge(I,O,X,Y,Yn,Z,Zn,T,P,PP) :-X=[A|L],Yn=[B|N],!,
    (if A<B then
	@O=[A], @X=L, @Y=Yn
    else
	@O=[B], @Y=N, @X=X).

append(Nil,L,L1) :- Nil=[],L=L1.
append(X,L,Y) :-[H|T]=X,[H1|M]=Y,
     H=H1,append(T,L,M).