> well, i think i have to agree ... if it wasnt for Wine's 0x40 descriptor.  
> But it certainly does not come free. We could have 3 TLS entries (0x40
> will be the last entry), and the copying cost is 9 cycles. (compared to 6
> cycles in the 2 entries case.) Good enough?
Or we could leave 0x40 fixed to 0x400 and use only 2.

This loses flexibility but anyway the only 2 apps that could use it are
dosemu and wine and I think that they already need to have it mapped at
0x400 for vm86 (no one uses 16-bit DLLs anymore).

Of course this is only valid if Win32 doesn't use it because otherwise
we would lose the ability to do null-pointer checking in programs using
Win32 DLLs (e.g. mplayer).