TODO

   1 short term:
   2 ----------
   3 - physical memory cache (reduce qemu-fast address space size to about 32 MB)
   4 - better code fetch (different exception handling + CS.limit support)
   5 - do not resize vga if invalid size.
   6 - avoid looping if only exceptions
   7 - handle fast timers + add explicit clocks
   8 - OS/2 install bug
   9 - cycle counter for all archs
  10 - TLB code protection support for PPC
  11 - add sysenter/sysexit and fxsr for L4 pistachio 686
  12 - basic VGA optimizations
  13 - disable SMC handling for ARM/SPARC/PPC (not finished)
  14 - see undefined flags for BTx insn
  15 - user/kernel PUSHL/POPL in helper.c
  16 - keyboard output buffer filling timing emulation
  17 - return UD exception if LOCK prefix incorrectly used
  18 - test ldt limit < 7 ?
  19 - tests for each target CPU
  20 - fix CCOP optimisation
  21 - fix all remaining thread lock issues (must put TBs in a specific invalid
  22   state, find a solution for tb_flush()).
  23 - fix arm fpu rounding (at least for float->integer conversions)
  24 - SMP support
  25
  26 lower priority:
  27 --------------
  28 - HDD geometry in CMOS (not used except for very old DOS programs)
  29 - suppress shift_mem ops
  30 - fix some 16 bit sp push/pop overflow (pusha/popa, lcall lret)
  31 - sysenter/sysexit emulation
  32 - optimize FPU operations (evaluate x87 stack pointer statically)
  33 - add IPC syscalls
  34 - use -msoft-float on ARM
  35 - use kernel traps for unaligned accesses on ARM ?
  36 - handle rare page fault cases (in particular if page fault in heplers or
  37   in syscall emulation code).
  38 - fix thread stack freeing (use kernel 2.5.x CLONE_CHILD_CLEARTID)
  39 - more syscalls (in particular all 64 bit ones, IPCs, fix 64 bit
  40   issues, fix 16 bit uid issues)
  41 - use page_unprotect_range in every suitable syscall to handle all
  42   cases of self modifying code.
  43 - use gcc as a backend to generate better code (easy to do by using
  44   op-i386.c operations as local inline functions).
  45 - add SSE2/MMX operations