\def\avr@debug#1{%
  \typeout{\the\avr@pc: #1}%
}

\def\avr@error#1{%
  \typeout{#1}\bye%
}


% Execution Engine
\def\avr@instr@step{%
  \avr@code@get{\avr@instr@current}%
  % Dispatch Instruction by prefix
  \expandafter\avr@instr@dispatch\avr@instr@current\@nnil%
  \relax%
}

\newcount\avr@instr@steps
\def\avr@instr@stepn#1{%
  \avr@instr@steps=#1%
  \def\avr@instr@stepn@helper{
    \ifnum \avr@instr@steps > 0%
      \advance \avr@instr@steps by -1\relax%
      \avr@instr@step%
      \avr@instr@stepn@helper%
    \fi%
  }%
  \avr@instr@stepn@helper%
}

\def\avr@instr@dispatch#1#2#3#4#5#6#7#8#9\@nnil{%
  \ifcsdef{avr@instr@#1#2#3#4#5#6#7#8#9}{%
    \csuse{avr@instr@#1#2#3#4#5#6#7#8#9}\@nnil%
  }{\ifcsdef{avr@instr@#1#2#3#4#5#6#7#8}{%
    \csuse{avr@instr@#1#2#3#4#5#6#7#8}#9\@nnil%
  }{\ifcsdef{avr@instr@#1#2#3#4#5#6#7}{%
    \csuse{avr@instr@#1#2#3#4#5#6#7}#8#9\@nnil%
  }{\ifcsdef{avr@instr@#1#2#3#4#5#6}{%
    \csuse{avr@instr@#1#2#3#4#5#6}#7#8#9\@nnil%
  }{\ifcsdef{avr@instr@#1#2#3#4#5}{%
    \csuse{avr@instr@#1#2#3#4#5}#6#7#8#9\@nnil%
  }{\ifcsdef{avr@instr@#1#2#3#4}{%
    \csuse{avr@instr@#1#2#3#4}#5#6#7#8#9\@nnil%
  }{\ifcsdef{avr@instr@#1#2#3}{%
    \csuse{avr@instr@#1#2#3}#4#5#6#7#8#9\@nnil%
  }{\ifcsdef{avr@instr@#1#2}{%
    \csuse{avr@instr@#1#2}#3#4#5#6#7#8#9\@nnil%
  }{\ifcsdef{avr@instr@#1}{%
    \csuse{avr@instr@#1}#2#3#4#5#6#7#8#9\@nnil%
  }{% Not found
    \avr@error{Unkown Instruction: #1#2#3#4#5#6#7#8#9}%
  }}}}}}}}}%
}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Helpers
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\def\avr@instr@gen@tworegs#1#2#3#4{%
  \avr@bin@msb@del{#3}{\avr@ADD@dddd}{\avr@ADD@d}%
  \avr@bin@msb@del{#4}{\avr@ADD@rrrr}{\avr@ADD@r}%
  \avr@code@set{#1\avr@ADD@r\avr@ADD@d\avr@ADD@dddd\avr@ADD@rrrr}{#2}%
}

\def\avr@instr@gen@regconst#1#2#3#4{%
  \avr@bin@msb@del{#3}{\avr@LDI@dddd}{\avr@LDI@d}%
  \avr@bin@nibble@high{#4}{\avr@LDI@H}%
  \avr@bin@nibble@low{#4}{\avr@LDI@L}%
  \avr@code@set{#1\avr@LDI@H\avr@LDI@dddd\avr@LDI@L}{#2}%
}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Arithmetic instructions
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% ADD -- Add without Carry
\def\avr@instr@ADD{\avr@instr@gen@tworegs{000011}}

\csdef{avr@instr@000011}#1#2#3#4#5#6#7\@nnil{%
  \def\avr@instr@extracarry{0}%
  \avr@reg@get{#1#7}{\avr@Rr}%
  \avr@reg@get{#2#3#4#5#6}{\avr@Rd}%
  \avr@debug{ADD - \%#2#3#4#5#6 <- #2#3#4#5#6 + \%#1#7}%
  \avr@debug{ADD - \avr@Rd <- \avr@Rd + \avr@Rr}%
  \def\avr@instr@adder@RrPreprocess{\avr@bit@id}%
  \csuse{avr@instr@adder@helper}%
  \avr@reg@set{\avr@Rx}{#2#3#4#5#6}%
  \avr@pc@inc%
}

% ADC -- Add with Carry
\def\avr@instr@ADC{\avr@instr@gen@tworegs{000111}}

\csdef{avr@instr@000111}#1#2#3#4#5#6#7\@nnil{%
  \avr@reg@get{#1#7}{\avr@Rr}%
  \avr@reg@get{#2#3#4#5#6}{\avr@Rd}%
  \avr@flag@get C \avr@instr@extracarry%
  \avr@debug{ADC - \%#2#3#4#5#6 <- #2#3#4#5#6 + \%#1#7}%
  \avr@debug{ADC - \avr@Rd <- \avr@Rd + \avr@Rr + \avr@instr@extracarry}%
  \def\avr@instr@adder@RrPreprocess{\avr@bit@id}%
  \csuse{avr@instr@adder@helper}%
  % Set the result register
  \avr@reg@set{\avr@Rx}{#2#3#4#5#6}%
  \avr@pc@inc%
}

% SUB -- Substract without carry
\def\avr@instr@SUB{\avr@instr@gen@tworegs{000110}}
\csdef{avr@instr@000110}#1#2#3#4#5#6#7\@nnil{%
  \avr@reg@get{#1#7}{\avr@Rr}%
  \avr@reg@get{#2#3#4#5#6}{\avr@Rd}%
  \def\avr@instr@extracarry{1}%
  \avr@debug{SUB - \%#2#3#4#5#6 <- #2#3#4#5#6 + \%#1#7}%
  \avr@debug{SUB - \avr@Rd <- \avr@Rd - \avr@Rr}%
  \def\avr@instr@adder@RrPreprocess{\avr@bit@negate}%
  \csuse{avr@instr@adder@helper}%
  % Set the result register
  \avr@reg@set{\avr@Rx}{#2#3#4#5#6}%
  \avr@pc@inc%
}
% SBC - Substract with Carry
\def\avr@instr@SBC{\avr@instr@gen@tworegs{000010}}
\csdef{avr@instr@000010}#1#2#3#4#5#6#7\@nnil{%
  \avr@reg@get{#1#7}{\avr@Rr}%
  \avr@reg@get{#2#3#4#5#6}{\avr@Rd}%
  \avr@flag@get C \@@carry%
  \xdef \avr@instr@extracarry {\avr@bit@negate \@@carry}%
  \avr@debug{SBC - \%#2#3#4#5#6 <- #2#3#4#5#6 + \%#1#7}%
  \avr@debug{SBC - \avr@Rd <- \avr@Rd - \avr@Rr - \@@carry}%
  \def\avr@instr@adder@RrPreprocess{\avr@bit@negate}%
  \csuse{avr@instr@adder@helper}%
  % Set the result register
  \avr@reg@set{\avr@Rx}{#2#3#4#5#6}%
  \avr@pc@inc%
}

% SUBI - Substract Immediate
\def\avr@instr@SUBI{\avr@instr@gen@regconst{0101}}
\csdef{avr@instr@0101}#1#2#3#4#5#6#7#8#9\@nnil{%
  \avr@reg@get{1#5#6#7#8}{\avr@Rd}%
  \def\avr@Rr{#1#2#3#4#9}%
  \def\avr@instr@extracarry{1}%
  \avr@debug{SUBI - \%#2#3#4#5#6 <- #2#3#4#5#6(=\avr@Rd) - \avr@Rr}%
  \def\avr@instr@adder@RrPreprocess{\avr@bit@negate}%
  \csuse{avr@instr@adder@helper}%
  % Set the result register
  \avr@reg@set{\avr@Rx}{1#5#6#7#8}%
  \avr@pc@inc%
}

% SBCI - Substract Immediate
\def\avr@instr@SBCI{\avr@instr@gen@regconst{0100}}
\csdef{avr@instr@0100}#1#2#3#4#5#6#7#8#9\@nnil{%
  \avr@reg@get{1#5#6#7#8}{\avr@Rd}%
  \def\avr@Rr{#1#2#3#4#9}%
  \avr@flag@get C \@@carry%
  \xdef \avr@instr@extracarry {\avr@bit@negate \@@carry}%
  \avr@debug{SBCI - \%#2#3#4#5#6 <- #2#3#4#5#6(=\avr@Rd) - \avr@Rr -\@@carry}%
  \def\avr@instr@adder@RrPreprocess{\avr@bit@negate}%
  \csuse{avr@instr@adder@helper}%
  % Set the result register
  \avr@reg@set{\avr@Rx}{1#5#6#7#8}%
  \avr@pc@inc%
}

% CP -- Compare without Carry
\def\avr@instr@CP{\avr@instr@gen@tworegs{000101}}

\csdef{avr@instr@000101}#1#2#3#4#5#6#7\@nnil{%
  \avr@reg@get{#1#7}{\avr@Rr}%
  \avr@reg@get{#2#3#4#5#6}{\avr@Rd}%
  \def\avr@instr@extracarry{1}%
  \avr@debug{CP - #2#3#4#5#6(=\avr@Rd) - \%#1#7(=\avr@Rr)}%
  \def\avr@instr@adder@RrPreprocess{\avr@bit@negate}%
  \csuse{avr@instr@adder@helper}%
  % Do not set the output register
  \avr@pc@inc%
}

% CPC -- Compare with Carry
\def\avr@instr@CPC{\avr@instr@gen@tworegs{000001}}

\csdef{avr@instr@000001}#1#2#3#4#5#6#7\@nnil{%
  \avr@reg@get{#1#7}{\avr@Rr}%
  \avr@reg@get{#2#3#4#5#6}{\avr@Rd}%
  \avr@flag@get C \@@carry%
  \xdef \avr@instr@extracarry {\avr@bit@negate \@@carry}%
  \avr@debug{CP - #2#3#4#5#6(=\avr@Rd) - \%#1#7(=\avr@Rr)}%
  \def\avr@instr@adder@RrPreprocess{\avr@bit@negate}%
  \csuse{avr@instr@adder@helper}%
  % Do not set the output register
  \avr@pc@inc%
}

\csdef{avr@instr@adder@helper}{%
  % Convert the Bitstring to Integer values
  \avr@bin@tocount{\avr@Rd}{\avr@accA}%
  \avr@bin@map{\avr@instr@adder@RrPreprocess}{\avr@Rr}{\avr@Rr}%
  \avr@bin@tocount{\avr@Rr}{\avr@accB}%
  \advance \avr@accA by \avr@accB\relax%
  \advance \avr@accA by \avr@instr@extracarry\relax%
  \avr@count@modulo@byte{\avr@accA}%
  \avr@count@tobin@b{\avr@accA}{\avr@Rx}%
  % Calculate the Flags
  \let\@@not=\avr@bit@negate%
  \let\@@and=\avr@bit@and%
  \let\@@or=\avr@bit@or%
  %% Carry
  \avr@bin@msb@get{\avr@Rr}{\@@R}%
  \avr@bin@msb@get{\avr@Rd}{\@@D}%
  \avr@bin@msb@get{\avr@Rx}{\@@X}%
  % \avr@debug{R: \@@R D: \@@D X:\@@X}%
  \def\avr@ADD@carry{%
    \@@or {\@@and \@@D {\@@not \@@X}}%
          {%
            \@@or{\@@and \@@R \@@D}%
                 {\@@and \@@R {\@@not \@@X}}}}%
  \avr@flag@set C {\avr@instr@adder@RrPreprocess{\avr@ADD@carry}}%
  % Two's Complement Overflow
  \def\@@tmp{\@@or%
    {\@@and \@@D {\@@and \@@R {\@@not \@@X}}}%
    {\@@and {\@@not \@@D} {\@@and {\@@not \@@R} \@@X}}}%
  \avr@flag@set V \@@tmp%
  % Half Carry
  \avr@bin@getbit{\avr@Rr}{3}{\@@R}%
  \avr@bin@getbit{\avr@Rd}{3}{\@@D}%
  \avr@bin@getbit{\avr@Rx}{3}{\@@X}%
  \def\avr@ADD@carry{%
    \@@or {\@@and \@@D {\@@not \@@X}}%
          {%
            \@@or{\@@and \@@R \@@D}%
                 {\@@and \@@R {\@@not \@@X}}}}%
  \avr@flag@set H {\avr@instr@adder@RrPreprocess{\avr@ADD@carry}}%
  %% Update Dependend Flags (N, Z, S)
  \avr@flags@update \avr@Rx%
}

% LDI -- Load Immediate Value
\def\avr@instr@LDI{\avr@instr@gen@regconst{1110}}
\def\avr@instr@SER#1#2{\avr@instr@gen@regconst{1110}{#1}{#2}{11111111}}
\csdef{avr@instr@1110}#1#2#3#4#5#6#7#8#9\@nnil{%
  \avr@debug{LDI - \%1#5#6#7#8 <- #1#2#3#4#9}%
  \avr@reg@set{#1#2#3#4#9}{1#5#6#7#8}%
  \avr@pc@inc%
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Branch Instructions
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Encode 6 Bit Value to PC Offset
\def\avr@instr@jump@enc#1#2{%
  \avr@count@tmpa=#1%
  \ifnum #1 < 0%
     \avr@count@tmpb=\avr@count@tmpa%
     \avr@count@tmpa=255%
     \advance \avr@count@tmpa by \avr@count@tmpb\relax%
     \advance \avr@count@tmpa by 1\relax%
  \fi%
  \avr@count@tobin@b{\avr@count@tmpa}{\@@res}%
  \avr@bin@msb@del{\@@res}{#2}{\@tempa}
}
\def\avr@instr@jump@dec#1#2{%
  \avr@bin@tocount{0#1}{\avr@count@tmpa}%
  \ifnum \avr@count@tmpa > 63%
     \avr@count@tmpb=\avr@count@tmpa%
     \avr@count@tmpa=-128%
     \advance \avr@count@tmpa by \avr@count@tmpb\relax%
  \fi%
  #2=\avr@count@tmpa\relax%
}

% BRBC -- Branch if Bit in SREG is cleared
\def\avr@instr@BRBC#1#2#3{% ADD PC, Bit, Offset
  \avr@instr@jump@enc{#3}{\@@offset}%
  \avr@code@set{111101\@@offset#2}{#1}%
}

% BRBS -- Branch if Bit in SREG is set
\def\avr@instr@BRBS#1#2#3{% ADD PC, Bit, Offset
  \avr@instr@jump@enc{#3}{\@@offset}%
  \avr@code@set{111100\@@offset#2}{#1}%
}

% BRCC - Branch if Carry Cleared
\def\avr@instr@BRCC#1#2{% PC, Offset
  \avr@instr@BRBC{#1}{000}{#2}%
}
% BRSH - Branch if Same or Higher
\def\avr@instr@BRSH{\avr@instr@BRCC}

% BRCS - Branch if Carry Set
\def\avr@instr@BRCS#1#2{% PC, Offset
  \avr@instr@BRBS{#1}{000}{#2}%
}
% BRSH - Branch if Lower
\def\avr@instr@BRLO{\avr@instr@BRCS}


% BRHC - Branch if Half Carry Cleared
\def\avr@instr@BRHC#1#2{% PC, Offset
  \avr@instr@BRBC{#1}{101}{#2}%
}
% BRHS - Branch if Half Carry Set
\def\avr@instr@BRHS#1#2{% PC, Offset
  \avr@instr@BRBS{#1}{101}{#2}%
}

% BRID - Branch if Global Interrupt Disabled
\def\avr@instr@BRID#1#2{% PC, Offset
  \avr@instr@BRBC{#1}{111}{#2}%
}
% BRIE - Branch if Global Interrupt Enabled
\def\avr@instr@BRIE#1#2{% PC, Offset
  \avr@instr@BRBS{#1}{111}{#2}%
}

% BRMI - Branch if Minus
\def\avr@instr@BRMI#1#2{% PC, Offset
  \avr@instr@BRBS{#1}{010}{#2}%
}
% BRPL - Branch if Plus
\def\avr@instr@BRPL#1#2{% PC, Offset
  \avr@instr@BRBC{#1}{010}{#2}%
}
% BRNE - Branch if Not Equal
\def\avr@instr@BRNE#1#2{% PC, Offset
  \avr@instr@BRBC{#1}{001}{#2}%
}
% BREQ - Branch if Equal
\def\avr@instr@BREQ#1#2{% PC, Offset
  \avr@instr@BRBS{#1}{001}{#2}%
}

% BRTC - Branch if T flag cleared
\def\avr@instr@BRTC#1#2{% PC, Offset
  \avr@instr@BRTC{#1}{110}{#2}%
}
% BRTS - Branch if T flag set
\def\avr@instr@BRTS#1#2{% PC, Offset
  \avr@instr@BRTS{#1}{110}{#2}%
}

% BRVC - Branch if Overflow flag cleared
\def\avr@instr@BRVC#1#2{% PC, Offset
  \avr@instr@BRBC{#1}{011}{#2}%
}
% BRVS - Branch if Overflow flag set
\def\avr@instr@BRVS#1#2{% PC, Offset
  \avr@instr@BRBS{#1}{011}{#2}%
}

% BRGE - Branch if greater Equal (signed)
\def\avr@instr@BRGE#1#2{% PC, Offset
  \avr@instr@BRBC{#1}{100}{#2}%
}
% BRLT - Branch if less than (signed)
\def\avr@instr@BRLT#1#2{% PC, Offset
  \avr@instr@BRBS{#1}{100}{#2}%
}

% #1 = Value to be reached
\csdef{avr@instr@11110}#1#2#3#4#5#6#7#8#9\@nnil{
  \edef\@@required{\avr@bit@negate #1}%
  \def\@@offset{#2#3#4#5#6#7#8}%
  \def\@@bit{00000#9}%
  \avr@sreg@get{\@@sreg}%
  \avr@bin@tocount{\@@bit}{\avr@count@tmpa}%
  \edef\@@bit{\the\avr@count@tmpa}%
  \avr@bin@getbit{\@@sreg}{\@@bit}{\@@found}%
  \avr@count@tmpa=\@@required%
  \avr@count@tmpb=\@@found\relax%
  \avr@debug{BRB{CS} - (\@@sreg[\@@bit] == \@@required) ? +\@@offset : +0}
  \ifnum \avr@count@tmpa = \avr@count@tmpb%
     \avr@instr@jump@dec{\@@offset}{\avr@count@tmpa}%
     \avr@debug{BRB -- JUMP \the\avr@count@tmpa}%
     \avr@pc@add{\avr@count@tmpa}%
  \fi%
  \avr@pc@inc%
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Data transfert instructions
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% MOV
\def\avr@instr@MOV{\avr@instr@gen@tworegs{001011}}

\csdef{avr@instr@001011}#1#2#3#4#5#6#7\@nnil{%
  \avr@reg@get{#1#7}{\avr@Rr}%
  \avr@reg@set{\avr@Rr}{#2#3#4#5#6}%
  \avr@debug{MOV - #2#3#4#5#6 <- #1#7(=\avr@Rr)}
  \avr@pc@inc%
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Misc
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\def\avr@instr@BREAK#1{% BREAK PC
  \avr@code@set{1001010110011000}{#1}%
}

\csdef{avr@instr@1001010110011000}\@nnil{%
  \avr@debug{BREAK}%
  \avr@instr@steps=0\relax%
  \avr@pc@inc%
}

\def\avr@instr@NOP#1{% BREAK PC
  \avr@code@set{0000000000000000}{#1}%
}

\csdef{avr@instr@0000000000000000}\@nnil{%
  \avr@debug{NOP}%
  \avr@pc@inc%
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Logical Instructions
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\def\avr@instr@bitop@helper{%
  \avr@debug{\avr@instr@bitop  - {\avr@Rd} AND {\avr@Rr}}%
  \csuse{avr@bin@\avr@instr@bitop}{\avr@Rr}{\avr@Rd}{\avr@Rx}%
  \avr@flag@set V 0%
  \avr@flags@update \avr@Rx%
}

\def\avr@instr@AND{\avr@instr@gen@tworegs{001000}}
\def\avr@instr@TST#1#2{\avr@instr@gen@tworegs{001000}{#1}{#2}{#2}}
\csdef{avr@instr@001000}#1#2#3#4#5#6#7\@nnil{%
  \avr@reg@get{#1#7}{\avr@Rr}%
  \avr@reg@get{#2#3#4#5#6}{\avr@Rd}%
  \def\avr@instr@bitop{and}%
  \avr@instr@bitop@helper%
  % Set the result register
  \avr@reg@set{\avr@Rx}{#2#3#4#5#6}%
  \avr@pc@inc%
}

\def\avr@instr@ANDI{\avr@instr@gen@regconst{0111}}
\csdef{avr@instr@0111}#1#2#3#4#5#6#7#8#9\@nnil{%
  \avr@reg@get{1#5#6#7#8}{\avr@Rd}%
  \def\avr@Rr{#1#2#3#4#9}%
  \def\avr@instr@bitop{and}%
  \avr@instr@bitop@helper%
  % Set the result register
  \avr@reg@set{\avr@Rx}{1#5#6#7#8}%
  \avr@pc@inc%
}


\def\avr@instr@OR{\avr@instr@gen@tworegs{001010}}
\csdef{avr@instr@001010}#1#2#3#4#5#6#7\@nnil{%
  \avr@reg@get{#1#7}{\avr@Rr}%
  \avr@reg@get{#2#3#4#5#6}{\avr@Rd}%
  \def\avr@instr@bitop{or}%
  \avr@instr@bitop@helper%
  % Set the result register
  \avr@reg@set{\avr@Rx}{#2#3#4#5#6}%
  \avr@pc@inc%
}

\def\avr@instr@ORI{\avr@instr@gen@regconst{0110}}
\csdef{avr@instr@0110}#1#2#3#4#5#6#7#8#9\@nnil{%
  \avr@reg@get{1#5#6#7#8}{\avr@Rd}%
  \def\avr@Rr{#1#2#3#4#9}%
  \def\avr@instr@bitop{or}%
  \avr@instr@bitop@helper%
  % Set the result register
  \avr@reg@set{\avr@Rx}{1#5#6#7#8}%
  \avr@pc@inc%
}

\def\avr@instr@EOR{\avr@instr@gen@tworegs{001001}}
\def\avr@instr@CLR#1#2{\avr@instr@EOR{#1}{#2}{#2}}
\csdef{avr@instr@001001}#1#2#3#4#5#6#7\@nnil{%
  \avr@reg@get{#1#7}{\avr@Rr}%
  \avr@reg@get{#2#3#4#5#6}{\avr@Rd}%
  \def\avr@instr@bitop{xor}%
  \avr@instr@bitop@helper%
  % Set the result register
  \avr@reg@set{\avr@Rx}{#2#3#4#5#6}%
  \avr@pc@inc%
}



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