No BIOS MPFP structure with smp=92 and more

qemu 0.12.2, SeaBios 0.5.1, running qemu-system-x86_64.exe with option -smp.
If smp>=92 then no MP floating point structure present in 1 Mb. This may be verified by pmemsave 0 0x100000 in debugger and search for _MP_ signature in file.

qemu 0.10.5 (bios build 05/08/09) can smp=128 (and even 255 if not hangs :).

Host win 7 x64 RTM 7600.