--[[--------------------------------------------------------------------
  masks for instruction properties. The format is:
  bits 0-1: op mode
  bits 2-3: C arg mode
  bits 4-5: B arg mode
  bit 6: instruction set register A
  bit 7: operator is a test

  for OpArgMask:
  OpArgN - argument is not used
  OpArgU - argument is used
  OpArgR - argument is a register or a jump offset
  OpArgK - argument is a constant or register/constant
----------------------------------------------------------------------]]