Re: Help in getting application to access I/O space

Paul,

You talked about this code working for 16-bit quantities instead of 8-bit.
I need to do 32-bit.
Can this same technique be extended to 32-bits?
I am not an x86 assembly language expert, so if you could provide some more
pointers for how to do 32-bit I/O space accesses, that would be great.



"Paul G. Tobey [eMVP]" <p space tobey no spam AT no instrument no spam DOT
com> wrote in message news:%239IPKsZtGHA.4748@xxxxxxxxxxxxxxxxxxxxxxx
You can do it with some simple inline assembly. Again, remember the
restrictions on this and its lack of portability. No one is later going
to look at this code and think how smart you are...

BYTE inpb( USHORT addr )
{
BYTE val;
__asm
{
xor eax, eax
mov dx, addr
in al, dx
mov val, al
}

return val;
}

void outpb( USHORT addr, BYTE val )
{
__asm
{
mov dx, addr
mov al, val
out dx, al
}
}

Similar things would be done to do word-wide, rather than byte-wide,
outputs, if that's what your hardware requires.

Paul T.

"Andy Purcell" <Andy_Purcell@xxxxxxxxxxx> wrote in message
news:uCwISlZtGHA.4748@xxxxxxxxxxxxxxxxxxxxxxx
The processor is x86.
What code would I start to modify to create my own _inp() and _outp() for
r/w?




"Paul G. Tobey [eMVP]" <p space tobey no spam AT no instrument no spam
DOT com> wrote in message news:OrOFFnYtGHA.1504@xxxxxxxxxxxxxxxxxxxxxxx
What sort of a processor is it? If it's x86, there's a separate set of
instructions that access it and you could write your own versions of
_inp() and _outp() to read and write. If it's not an x86, then I/O =
memory, so you'll want to use MmMapIoSpace() with appropriate
parameters. Based on that address, I'm guessing x86.

A twist is that it's also possible that your platform uses bus-relative
addresses, in which case BusTransBusAddrToVirtual() would be more
appropriate. Are you sure you shouldn't be doing this in a driver and
not the application?

Paul T.

"Andy Purcell" <Andy_Purcell@xxxxxxxxxxx> wrote in message
news:%23dbEJiYtGHA.1512@xxxxxxxxxxxxxxxxxxxxxxx
I need to write CE app to manipulate my CPU GPIO outputs. The
documentation for the CPU registers that control GPIO signals says that
the registers are mapped as offsets into "I/O Space". The base address
is 0xF0.

So the question is - how can my application access these registers?
- can I use WRITE_PORT_ULONG()?
- must I map this space using some API?











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