a) If the real EM (EMr)
bit is set, the host is supplying or is capable of supplying floating point
emulation.
b) If the MPv bit is
not set, the host may not need to save the coprocessor state for this virtual
machine to improve system performance.
c) MPr bit setting should
be consistent with the setting of coprocessor type information. Ignore
MPr bit information if it is in conflict with the coprocessor type information.
d) If the virtual EM
(EMv) bit is set, the host delivers all coprocessor exceptions to the client,
and the client is performing its own floating point emulation (whether
or not a coprocessor is present or the host also has a floating point emulator).
In other words, if the EMv bit is set, the host sets the EM bit in the
real CR0 while the virtual machine is active, and reflects coprocessor
not present faults (INT 07h) to the virtual machine.
e) A client can determine
the CPU type with DPMI function 0400h but a client should not draw any
conclusions about the presence or absence of a coprocessor based on the
CPU type alone.
f) DOS/32 Advanced DPMI
will not distinguish between 80387 and 80487 (80486 with built-in FPU).
That is, if the CPU installed in machine is 80486SX, and an 80387 FPU is
present, DOS/32 Advanced DPMI will report the presence of an 80487.
g) DOS/32 Advanced DPMI
does not have a built-in FPU emulator. That is, when client enables FPU
emulation (using Set Coprocessor Emulation DPMI function 0E01h), but does
not handle the exception 07h (Coprocessor not available), the first instruction
executed by the CPU that uses FPU will cause exception 07h which will be
trapped by DOS/32 Advanced which in its turn will terminate the client
and return to DOS with an error message.