byteOpFlag: bit{1}

RRC := b000
SWPB:= b001
RRA := b010
SXT := b011
PUSH:= b100
CALL:= b101
RETI:= b110

oneOpCode: bit{3} :=
  RRC | SWPB | RRA | SXT | PUSH | CALL | RETI

JNE := b000
JEQ := b001
JNC := b010
JC  := b011
JN  := b100
JGE := b101
JL  := b110
JMP := b111

jumpCondition: bit{3} :=
  JNE | JEQ | JNC | JC | JN | JGE | JL | JMP

MOV := b0100
ADD := b0101
ADDC:= b0110
SUBC:= b0111
SUB := b1000
CMP := b1001
DADD:= b1010
BIT := b1011
BIC := b1100
BIS := b1101
XOR := b1110
AND := b1111

twoOpCode: bit{4} :=
  MOV | ADD | ADDC | SUBC | SUB | CMP | DADD | BIT | BIC | BIS | XOR | AND

Symbolic := b1
Absolute := b1
RegisterDirect := b0
Indexed := b1

twoOpDestMode: bit{1} :=
  RegisterDirect | Indexed | Absolute | Symbolic

NextWord := b11
Const0 := b00
Const1 := b01
Const2 := b10
Const4 := b10
Const8 := b11
ConstNeg1 := b11
RegisterDirect := b00
Indexed := b01
RegisterIndirect := b10
IndirectAutoInc := b11

twoOpSourceMode: bit{2} :=
  NextWord | Const0 | Const1 |
  Const2 | Const4 | Const8 |
  ConstNeg1 | RegisterDirect | Indexed |
  RegisterIndirect | IndirectAutoInc

oneOpDestMode: bit{2} := twoOpSourceMode

twoOpDestModePrime :=
  Symbolic:b0000 |
  Absolute:b0010 |
  RegisterDirect:register |
  Indexed:register

# replace with register names!
twoOpSourceModePrime :=
  NextWord:b0000
  Const4:b0010
  Const8:b0010
  Const0:b0011
  Const1:b0011
  Const2:b0011
  ConstNeg1:b0011
  RegisterDirect:register
  Indexed:register
  RegisterIndirect:register
  IndirectAutoInc:register

sourceReg: bit{4}
destReg: bit{4} := sourceReg

noOp := b001:jumpCondition:pcOffset
oneOp:= b000100:oneOpCode:byteOpFlag:oneOpDestMode:destReg
twoOp := twoOpCode:sourceReg:twoOpDestMode:byteOpFlag:twoOpSourceMode:destReg
twoOpRewrite $= twoOp =>
  twoOpCode:byteOpFlag:twoOpSourceMode:sourceReg:sourceReg:twoOpDestMode:destReg:destReg
twoOpPrime := twoOpCode:byteOpFlag:twoOpSourceModePrime:sourceReg:twoOpDestModePrime:destReg

root := oneOp | twoOp | noOp