--- M6502/M6502.pm	2007/07/30 14:02:31	25
+++ M6502/M6502.pm	2007/07/31 12:35:02	51
@@ -3,17 +3,152 @@
 use strict;
 use warnings;
 
-# Dobrica Pavlinusic, <dpavlin@rot13.org> 07/30/07 13:23:19 CEST
-#
-# Simple Orao emulation
+use Data::Dump qw/dump/;
+use Carp qw/confess/;
+use Exporter 'import';
+our @EXPORT = qw'@mem $PC $A $P $X $Y $S $IPeriod $run_for $debug';
 
-my $mem = (0) x 0x10000;	# 64M
+=head1 NAME
+
+M6502 - perl bindings for 6502 emulator
+
+=cut
+
+my $debug = 0;
+
+our $VERSION = qw(0.0.1);
+
+our @mem = (0xff) x 0x10000;	# 64M
 
 # program counter
 our $PC = 0xbeef;
 # CPU registars
 our ( $A, $P, $X, $Y, $S ) = (0) x 5;
 # Set IPeriod to number of CPU cycles between calls to Loop6502
-our $IPeriod = 20000;
+our $IPeriod = 1;
+# Exec6502 cycles
+our $run_for = 0;
+
+=head1 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
+
+  $byte = read( $address );
+
+=cut
+
+sub read {
+	my ($addr) = @_;
+	my $byte = $mem[$addr];
+	warn "## M6502::read(",dump(@_),") = ",dump( $byte ),"\n" if $debug;
+	return $byte;
+}
+
+=head2 write
+
+Write into emory
+
+  write( $address, $byte );
+
+=cut
+
+sub write {
+	warn "## M6502::write(",dump(@_),")\n" if $debug;
+	my ($addr,$byte) = @_;
+	$mem[$addr] = $byte;
+}
+
+=head2 poke_code
+
+Write series of bytes into memory passing through MMU (C<read> and C<write>)
+functions. If you don't want to trigger MMU, use C<write_chunk>.
+
+  $emu->poke_code( 0xbeef, 0xff, 0x00, 0xff, 0x00, 0xaa );
+
+=cut
+
+sub poke_code {
+	my $self = shift;
+	my $addr = shift;
+	warn sprintf("## M6502::poke_code(%04x,%s)\n", $addr, dump( @_ )) if $self->debug;
+	#$mem[$addr++] = $_ foreach @_;
+	# call low-level write
+	Arch::write($addr++, $_) foreach @_;
+}
+
+=head2 ram
+
+Read series of bytes into memory without MMU interaction
+
+  my @code = $emu->ram( 0xc000, 0xc1000 );
+
+=cut
+
+sub ram {
+	my $self = shift;
+	my ( $from, $to ) = @_;
+	warn sprintf("## M6502::ram(%04x,%04x)\n", $from, $to) if $self->debug;
+	return @mem[ $from .. $to ];
+}
+
+=head2 write_chunk
+
+Low-level update of memory, overriding user specified MMU functions C<read> and C<write>
+
+  $emu->write_chunk( $address, $chunk_of_data );
+
+=cut
+
+sub write_chunk {
+	my ($self, $addr, $chunk) = @_;
+	my $len = length($chunk);
+	splice @mem, $addr, $len, unpack('C*', $chunk);
+}
+
+=head2 prompt
+
+Call this after C<< $run_for >> cycles have been run on processor
+
+=cut
+
+sub prompt {
+	warn "prompt -- you should override this\n";
+	return 1;
+}
+
+=head2 push_R
+
+called by C<perl.c> to push changes in registars back to perl variables
+
+=cut
+
+sub push_R {
+	warn "## M6502::push_R(",dump(@_),")\n" if $debug;
+	my ( $a, $p, $x, $y, $s, $pc ) = @_;
+	$PC = $pc;
+	$S=$s; $X=$x; $Y=$y; $P=$p; $A=$a;
+	dump_R();
+}
+
+=head2 dump_R
+
+helper function which dumps registers
+
+=cut
+
+sub dump_R {
+	warn sprintf("## M6502::dump_R PC: %04x A:%02x P:%02x X:%02x Y:%02x S:%02x\n", $PC, $A, $P, $X, $Y, $S) if $debug;
+}
 
 1;