config: Do not instantiate membus when using ruby
This patch moves the instantiation of system.membus in se.py to the area of
code where classic memory system has been dealt with. Ruby does not require
this bus and hence it should not be instantiated.
Added tag stable_2013_06_16 for changeset 07352f119e48
x86: Fix the flag handling code in FABS and FCHS

This changeset fixes two problems in the FABS and FCHS
implementation. First, the ISA parser expects the assignment in
flag_code to be a pure assignment and not an and-assignment, which
leads to the isa_parser omitting the misc reg update. Second, the FCHS
and FABS macro-ops don't set the SetStatus flag, which means that the
default micro-op version, which doesn't update FSW, is executed.
x86: Add helper functions to access rflags

The rflags register is spread across several different registers. Most
of the flags are stored in MISCREG_RFLAGS, but some are stored in
microcode registers. When accessing RFLAGS, we need to reconstruct it
from these registers. This changeset adds two functions,
X86ISA::getRFlags() and X86ISA::setRFlags(), that take care of this
magic.
kvm: Use the address finalization code in the TLB

Reuse the address finalization code in the TLB instead of replicating
it when handling MMIO. This patch also adds support for injecting
memory mapped IPR requests into the memory system.
x86: Make fprem like the fprem on a real x87

The current implementation of fprem simply does an fmod and doesn't
simulate any of the iterative behavior in a real fprem. This isn't
normally a problem, however, it can lead to problems when switching
between CPU models. If switching from a real CPU in the middle of an
fprem loop to a simulated CPU, the output of the fprem loop becomes
correupted. This changeset changes the fprem implementation to work
like the one on real hardware.
x86: Make the boot state VMX compliant

This patch allows the default x86 state to be used when by CPUs that
use hardware virtualization.
x86: Initialize the MXCSR register
x86: Fix loading of floating point constants

This changeset actually fixes two issues:

 * The lfpimm instruction didn't work correctly when applied to a
   floating point constant (it did work for integers containing the
   bit string representation of a constant) since it used
   reinterpret_cast to convert a double to a uint64_t. This caused a
   compilation error, at least, in gcc 4.6.3.

 * The instructions loading floating point constants in the x87
   processor didn't work correctly since they just stored a truncated
   integer instead of a double in the floating point register. This
   changeset fixes the old microcode by using lfpimm instruction
   instead of the limm instructions.
x86: Add support for maintaining the x87 tag word

The current implementation of the x87 never updates the x87 tag
word. This is currently not a big issue since the simulated x87 never
checks for stack overflows, however this becomes an issue when
switching between a virtualized CPU and a simulated CPU. This
changeset adds support, which is enabled by default, for updating the
tag register to every floating point microop that updates the stack
top using the spm mechanism.

The new tag words is generated by the helper function
X86ISA::genX87Tags(). This function is currently limited to flagging a
stack position as valid or invalid and does not try to distinguish
between the valid, zero, and special states.