--- VRac.pm	2007/08/04 20:28:51	128
+++ VRac.pm	2007/08/05 13:27:27	145
@@ -12,7 +12,7 @@
 
 =head1 NAME
 
-VRac - Virtualno Računalo
+VRac - Virtualno Računalo
 
 =head1 VERSION
 
@@ -27,7 +27,7 @@
 Emulator of 8-bit architectures based on L<M6502> or L<Z80> emulation.
 
 This project is homage to 8-bit computers in Croatia and former Yugoslavia
-from 1980-1990. Word B<vrac> means also I<wizzard> in Croatian.
+from 1980-1990. Word B<vrac> means also I<wizard> in Croatian.
 
 =cut
 
@@ -49,17 +49,43 @@
 	confess "please implement $self::run\n";
 }
 
-=head2 jump
 
-Start execution from some location (modify PC)
+=head1 Memory management
+
+VRac implements callback for all I/O operations. This was main reason why
+L<Acme::6502> module with tied memory was too slow to emulate L<Orao>, so I
+had to write C binding for L<M6502>.
+
+B<This functions will die with stack trace when called>. They should be
+implemented for each architecture.
 
 =cut
 
-sub jump {
+=head2 read
+
+Read from memory
+
+  $byte = read( $address );
+
+=cut
+
+sub read {
 	my $self = shift;
-	confess "please implement $self::jump\n";
+	confess "please implement $self::read()";
 }
 
+=head2 write
+
+Write into emory
+
+  write( $address, $byte );
+
+=cut
+
+sub write {
+	my $self = shift;
+	confess "please implement $self::write()";
+}
 
 =head1 Helper functions
 
@@ -121,12 +147,16 @@
 	$from ||= 0;
 	$to ||= 0xffff;
 
-	open(my $fh, '>', $path) || die "can't open $path: $!";
-	print $fh $self->read_chunk( $from, $to );
-	close($fh);
+	if ( open(my $fh, '>', $path) ) {
+		print $fh $self->read_chunk( $from, $to );
+		close($fh);
+
+		my $size = -s $path;
+		warn sprintf "saved %s %04x-%04x %d %x bytes\n", $path, $from, $to, $size, $size;
+	} else {
+		warn "can't create $path: $!";
+	}
 
-	my $size = -s $path;
-	warn sprintf "saved %s %d %x bytes\n", $path, $size, $size;
 }
 
 =head2 hexdump
@@ -152,37 +182,21 @@
 	);
 }
 
-=head1 Memory management
+=head2 append_to_file
 
-VRac implements all I/O using mmap addresses. This was main reason why
-L<Acme::6502> was just too slow to handle it.
+  $self->append_to_file( '/path/to/file', $byte, $byte ... );
 
 =cut
 
-=head2 read
-
-Read from memory
-
-  $byte = read( $address );
-
-=cut
-
-sub read {
+sub append_to_file {
 	my $self = shift;
-	confess "please implement $self::read()";
-}
+	my $path = shift || confess "no path?";
+	my $bytes = join('', @_);
 
-=head2 write
+	open(my $fh, '>>', $path) || confess "can't open $path: $!";
 
-Write into emory
-
-  write( $address, $byte );
-
-=cut
-
-sub write {
-	my $self = shift;
-	confess "please implement $self::write()";
+	print $fh $bytes;
+	warn sprintf("## append_to_file('%s',%s)\n", $path, dump($bytes));
 }
 
 =head1 Command Line
@@ -330,6 +344,12 @@
 	return $run_for;
 }
 
+=head1 SEE ALSO
+
+Components: L<M6502>, L<Z80>, L<Screen>, L<Tape>
+
+Emulators: L<Orao>, L<Galaksija>
+
 =head1 AUTHOR
 
 Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >>