--- M6502/M6502.pm	2007/08/01 22:25:37	86
+++ M6502/M6502.pm	2007/08/02 13:04:29	94
@@ -15,9 +15,11 @@
 
 M6502 - perl bindings for M6502 CPU emulator
 
+=head1 FUNCTIONS
+
 =cut
 
-my $debug = 1;
+our $debug = 0;
 
 our @mem = (0xff) x 0x10000;	# 64M
 
@@ -37,47 +39,43 @@
 # Exec6502 cycles
 our $run_for = 0;
 
-=head1 FUNCTIONS
-
 =head2 init
 
-Called before C<Run6502>
-
-=cut
-
-sub init {
-	my $self = shift;
-	warn "inside init low-level M6502 from $self\n";
-};
-
-=head2 read
-
-Read from memory
+Setup read and write memory hooks (to implement memory mapped devices)
 
-  $byte = read( $address );
+  $init->(
+	read => sub {
+		return $mem[$_[0]];
+	},
+	write => sub {
+		$mem[$_[0]] = $_[1];
+	},
+  );
 
 =cut
 
-sub read {
-	my ($addr) = @_;
-	my $byte = $mem[$addr];
-	warn "## M6502::read(",dump(@_),") = ",dump( $byte ),"\n" if $debug;
-	return $byte;
-}
-
-=head2 write
-
-Write into emory
+our $_rw_hooks = {
+	read => sub {
+		warn sprintf("# callback read(%04x) not implemented\n", @_) if $debug;
+		return $mem[$_[0]];
+	},
+	write => sub {
+		warn sprintf("# callback write(%04x,%02x) not implemented", @_) if $debug;
+		$mem[$_[0]] = $_[1];
+	},
+};
 
-  write( $address, $byte );
+sub init {
+	my $self = shift;
+	my $args = {@_};
+	warn "inside init low-level M6502 from ",ref($self),"\n";
 
-=cut
+	foreach my $p ( qw/read write/ ) {
+		confess "need $p argument as coderef" unless ( $args->{$p} && ref($args->{$p}) eq 'CODE' );
+		$_rw_hooks->{$p} = $args->{$p};
+	}
 
-sub write {
-	warn "## M6502::write(",dump(@_),")\n" if $debug;
-	my ($addr,$byte) = @_;
-	$mem[$addr] = $byte;
-}
+};
 
 =head2 poke_code
 
@@ -94,7 +92,7 @@
 	warn sprintf("## M6502::poke_code(%04x,%s)\n", $addr, dump( @_ )) if $self->debug;
 	#$mem[$addr++] = $_ foreach @_;
 	# call low-level write
-	Arch::write($addr++, $_) foreach @_;
+	$_rw_hooks->{write}->( $addr++, $_ ) foreach @_;
 }
 
 =head2 ram
@@ -137,18 +135,84 @@
 	return 1;
 }
 
-=head2 push_R
+=head1 XS Callbacks
+
+This functions are called from C<M6502.xs>
+
+=head2 _read
+
+Read from memory C callback
+
+  $byte = M6502::_read( $address );
+
+=cut
+
+sub _read {
+	return $_rw_hooks->{read}->( @_ );
+}
+
+=head2 _write
+
+Write into memory C callback
+
+  M6502:_write( $address, $byte );
+
+=cut
+
+sub _write {
+	return $_rw_hooks->{write}->( @_ );
+}
+
+=head2 _update_perl_R
 
-called by C<perl.c> to push changes in registars back to perl variables
+called by C<M6502.xs> to push changes in registars back to perl variables
 
 =cut
 
-sub push_R {
-	warn "## M6502::push_R(",dump(@_),")\n" if $debug;
+sub _update_perl_R {
+	warn "## M6502::update_perl_R(",dump(@_),")\n" if $debug;
 	( $A, $P, $X, $Y, $S, $PC, $IPeriod, $ICount, $IRequest, $IAutoReset, $TrapBadOps, $Trap, $Trace ) = @_;
 	dump_R();
 }
 
+=head1 XS
+
+Following functions are implemented in C<M6502.xs> and exported to perl.
+
+=head2 set_debug
+
+  M6502::set_debug( 0 );
+
+=head2 get_debug
+
+  my $debug = M6502::set_debug();
+
+=head2 reset
+
+Reset 6502 CPU, reading PC from C<0xfffc>
+
+  M6502::reset();
+
+=head2 update_C_R
+
+Push perl notion of register values to CPU emulator
+
+  M6502::update_C_R();
+
+=head2 update_perl_R
+
+Update perl notion of register values
+
+  M6502::update_perl_R();
+
+=head2 exec
+
+Execute cpu for specified number of cycles
+
+  my $cycles_left = M6502::exec( $execute_cpu_cycles );
+
+=head1 Helpers
+
 =head2 dump_R
 
 helper function which dumps registers in humanly readable form
@@ -167,6 +231,27 @@
 	return $dump;
 }
 
+=head2 debug
+
+Turn perl and C-level debugging on/off
+
+  $emu->debug( 0 );
+  $emu->debug( 1 );
+  print $emu->debug;
+
+=cut
+
+sub debug {
+	my $self = shift;
+	my $value = shift;
+	if (defined($value)) {
+		$debug = M6502::set_debug($value);
+	} else {
+		$debug = M6502::get_debug();
+	}
+	return $debug;
+}
+
 =head1 SEE ALSO
 
 L<Orao> is sample implementation using this module