Machine Code..._(re)

Wed, 4 Jun 1997 22:51:11 +0200 (MET DST)

Hi!  Just cleaning up a little ...

According to PredatorZeta:
> 
> Type
> Byteint = __byte__ Integer;
> Byte = __unsigned__ Byteint;
> Shortint =__short__ Integer;
> Word16 = __unsigned__ Shortint;

`ByteInt', `Byte', and `ShortInt' like above are already built-in in
recent (alpha) versions of GPC.  `Word16' also exists but is named
`ShortWord'.

> Function Inportw(port : integer) : word16;
> var temp : word16=0;
> begin
> Asm("inw %%dx, %%ax" : "=a" (temp) : "d" (port));
> Inportw:=temp;
> end;
>
> Function Inportb(port : integer) : byte;
> var temp : byte=0;
> begin
> Asm("inw %%dx, %%al" : "=a" (temp) : "d" (port));
> Inportb:=temp;
> end;

This can be abbreviated further (and indented;-):


    Function InPortW ( port: Integer ) result: ShortWord;

    begin (* InPortW *)
      asm ( 'inw %%dx, %%ax' : '=a' ( result ) : 'd' ( port ) );
    end (* InPortW *);


    Function InPortB ( port: Integer ) result: Byte;

    begin (* InPortB *)
      asm ( 'inw %%dx, %%al' : '=a' ( result ) : 'd' ( port ) );
    end (* InPortB *);


(NOT TESTED, sorry!)

PredatorZeta, are you sure that it's `inw' in the second case,
not `inb'?

BTW, you can even use these as procedures in your program without loss of
speed:  With full optimization `-O3', GPC will automatically inline the
above.

Hope this helps,

    Peter

 Dr. rer. nat. [970604] Peter Gerwinski, Essen, free physicist and programmer
peter.gerwinski@uni-essen.de - http://home.pages.de/~peter.gerwinski/ [970201]
 maintainer GNU Pascal [970510] - http://home.pages.de/~gnu-pascal/ [970125]

Peter Gerwinski (peter@agnes.dida.physik.uni-essen.de)