low-level routines

[Daan Vreeken [PA4DAN]]

On Sunday 20 April 2003 04:17, RMH wrote:
> Hello gentlemen,
>
> could you point me to some function(s) used by FreeBSD to read\write values
> from\to hardware ports? I remember outp\inp (or outportb\inportb for
> Borland Turbo C) from DOS times, but these of course don't work for UNIX...

To read/write io ports directly on FreeBSD, you need to open /dev/io
After your process has successfully opened /dev/io you can read/write ports 
with these pieces of inline-assembly :

unsigned char inp(unsigned short Port)
{
        unsigned char   Data = 0;
 
        __asm __volatile("inb %%dx,%0" : "=a" (Data) : "d" (Port) );
 
        return Data;
}

void outp(unsigned short Port, unsigned char Data)
{
        unsigned char D = Data;
 
        __asm __volatile("outb %0,%%dx" : : "a" (D), "d" (Port) );
}


Here's a link to some code that I use to write to the parallel port directly :
http://danovitsch.dnsq.org/cgi-bin/gpl/cat.cgi/lampd/v1.0?lampd.c

grtz,
Daan