tcg/TODO

   1 - Add new instructions such as: andnot, ror, rol, setcond, clz, ctz,
   2   popcnt.
   3
   4 - See if it is worth exporting mul2, mulu2, div2, divu2.
   5
   6 - Support of globals saved in fixed registers between TBs.
   7
   8 Ideas:
   9
  10 - Move the slow part of the qemu_ld/st ops after the end of the TB.
  11
  12 - Change exception syntax to get closer to QOP system (exception
  13   parameters given with a specific instruction).
  14
  15 - Add float and vector support.