> Your most important comment:
>
> > I am trying to read/write registers in the FPGA.
>
> The FPGA interface uses a 16-bit interface, and
> since the TS example code uses PEEK and POKE
> routines to implement accesses to ensure that
> *specific assembly instructions* are used to
> access the FPGA interface locations, then I'd
> be wary of letting the compiler just select
> any old memory instruction it likes.
Note that writing driver code such that it uses
specific assembly instructions is not uncommon.
In Linux drivers for PCI interfaces you're supposed
to use readl(), writel(), readb(), writeb() etc.
These routines perform little-endian accesses no
matter what the processor, since the PCI bus is
defined as little-endian.
On PowerPC processor, out_be32(), in_be32() are
used to generate 32-bit processor calls.
I haven't looked at the implementations, but I suspect
some of these commands probably have flush routines
to maintain instruction ordering, or you have to
include those commands to make sure your write
gets to your hardware, before you go and read from
it, eg. write-to-enable, followed by a polling routine,
or ISR, etc.
They key thing is that; using pointers to access
hardware registers is generally *not* recommended.
Cheers,
Dave
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