- Add new instructions such as: andnot, ror, rol, setcond, clz, ctz,

popcnt.

- See if it is worth exporting mul2, mulu2, div2, divu2.

- Support of globals saved in fixed registers between TBs.

Ideas:

- Move the slow part of the qemu_ld/st ops after the end of the TB.

- Change exception syntax to get closer to QOP system (exception

parameters given with a specific instruction).

- Add float and vector support.