Optionally, make memory access helpers take a parameter for CPUState
instead of relying on global env.

On most targets, perform simple moves to reorder registers. On i386,
switch from regparm(3) calling convention to standard stack-based
version.
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

Use stack based calling convention (GCC default) for interfacing with
generated code instead of register based convention (regparm(3)).
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

Add some comments to describe each file.
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5115 c046a42c-6fe2-441c-8c8c-71466251a162