porting from Meridian Ada to Gnat

porting from Meridian Ada to Gnat

[DRW HOLTON]

I'm porting a DOS program from Meridian Open Ada (ver. 4.1.4) to Gnat
and have come up against a minor problem. The program uses the Port
package from the DOS Environment Library to access the 80x86 I/O
ports. For example the specification of the in_bye function is:

	function in_word (port_number : integer) return integer;

I would like re-write this package for Gnat (unless someone has
already done so, in which case please let me know!), which should be
really simple since there is a close correspondence between the
subprograms in the package and 80x86 assembly language instructions
(e.g. in_word is just a variant of the IN instruction). However I
don't know how best to go about doing this - should I write small
assembly language (or even C) modules and import them? Can I inline
the assembly language directly in the Ada package? I would prefer the
latter option since it is more self contained, but don't know how to
do it or even if it is possible. (In case it's important, I'm using
the ez2load distribution of gnat 3.05.)

I'd be grateful for any pointers or help. Please cc me any answers
since news isn't always reliable here.

TIA,

	Rob

Re: porting from Meridian Ada to Gnat

[Jerry van Dijk]

van Dijk, you moron, why can't you pay attention:

>	   return Integer (Inport_Word (Integer (Port_Number)));

should, of course, be:

return Integer (Inport_Word 
  (Unsigned_16 (Unsigned_32 (Port_Number) And 16#FF#)));

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