TODO

   1 - tests for each target CPU
   2 - ppc qemu test
   3 - optimize FPU operations (evaluate x87 stack pointer statically) and
   4   fix cr0.TS emulation
   5 - fix some 16 bit sp push/pop overflow
   6 - sysenter/sysexit emulation
   7 - finish segment ops (call far, ret far, load_seg suppressed)
   8 - fix CCOP optimisation
   9 - fix all remaining thread lock issues (must put TBs in a specific invalid
  10   state, find a solution for tb_flush()).
  11 - cpu loop optimisation (optimise ret case as the cpu state does not change)
  12 - fix arm fpu rounding (at least for float->integer conversions)
  13
  14 lower priority:
  15 --------------
  16 - add IPC syscalls
  17 - SMP support
  18 - use -msoft-float on ARM
  19 - use kernel traps for unaligned accesses on ARM ?
  20 - handle rare page fault cases (in particular if page fault in heplers or
  21   in syscall emulation code).
  22 - fix thread stack freeing (use kernel 2.5.x CLONE_CHILD_CLEARTID)
  23 - more syscalls (in particular all 64 bit ones, IPCs, fix 64 bit
  24   issues, fix 16 bit uid issues)
  25 - use page_unprotect_range in every suitable syscall to handle all
  26   cases of self modifying code.
  27 - use gcc as a backend to generate better code (easy to do by using
  28   op-i386.c operations as local inline functions).
  29 - add SSE2/MMX operations