#!/usr/bin/perl
#
# 8259A
#

use strict;
use warnings;

use Getopt::Std;

sub outb
{
    my $data = shift;
    my $port = shift;

    open(IO, "> /dev/port") || die "open /dev/port: $!\n";
    sysseek(IO, $port, 0) || die;
    my $x = pack("C", $data);
    syswrite(IO, $x, 1);
    close(IO);
}

sub inb
{
    my $port = shift;
    my $data;

    open(IO, "/dev/port") || die "open /dev/port: $!\n";
    sysseek(IO, $port, 0) || die;
    sysread(IO, $data, 1);
    close(IO);

    return unpack("C", $data);
}

sub set_edge_level
{
    my $irq = shift;
    my $to = shift;
    my $mask = 1 << ($irq & 7);
    my $port = 0x4d0 + ($irq >> 3);
    my $val = inb($port);

    if ($to eq "edge") {
	outb($val & ~$mask, $port);
    } else {
	outb($val | $mask, $port);
    }
    print "irq $irq: -> $to\n";
}

our($opt_e, $opt_l);
getopts('e:l:');

if ($opt_e and ($opt_e < 15)) {
    set_edge_level($opt_e, "edge");
} elsif ($opt_l and ($opt_l < 15)) {
    set_edge_level($opt_l, "level");
}

foreach my $irq (0..15) {
    my $mask = 1 << ($irq & 7);
    my $port = 0x4d0 + ($irq >> 3);
    my $val = inb($port);

    printf "irq %d: %02x, %s\n", $irq, $val, ($val & $mask) ? "level" : "edge";
}