Direct memory access

[Gordy <gbissell@coventry.ac.uk>]

I'm using GNAT v3.11 for IBM PC platforms. 

I'm trying to write some code to allow direct access to memory (for 
testing memory on an embedded system). I simply want something like 'C' 
pointers, so I can write/read values to a given memory address.

I've had a look at the Machine_Code package (to write my own functions) 
but there must be a better way (i.e is there a function in the System 
package which will allow writes to memory given a value and a 
System.Address)?

Any help greatly appreciated.

Gordon.