VRac/M6502/M6502.pm

package M6502;

use strict;
use warnings;

use Data::Dump qw/dump/;
use Carp qw/confess/;
use Exporter 'import';
our @EXPORT = qw'@mem $PC $A $P $X $Y $S $IPeriod';

=head1 NAME

M6502 - perl bindings for 6502 emulator

=cut

my $debug = 1;

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 ) = (0x42) x 5;
# Set IPeriod to number of CPU cycles between calls to Loop6502
our $IPeriod = 1;

=head1 init

Called before C<Run6502>

=cut

sub init {
        my $self = shift;
        warn dump(@_);
        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 "# read(",dump(@_),") = ",dump( $byte ),"\n" if $debug;
        return $byte;
}

=head2 write

Write into emory

  write( $address, $byte );

=cut

sub write {
        warn "# write(",dump(@_),")\n" if $debug;
        my ($addr,$byte) = @_;
        $mem[$addr] = $byte;
}

=head2 poke_code

Write series of bytes into memory without passing through MMU

  $emu->poke_code( 0xbeef, 0xff, 0x00, 0xff, 0x00, 0xaa );

=cut

sub poke_code {
        my $self = shift;
        my $addr = shift;
        warn sprintf("# poke_code(%04x,%s)\n", $addr, dump( @_ )) if $self->debug;
        $mem[$addr++] = $_ foreach @_;
}

=head2 write_chunk

  $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 ram

Read searies of bytes from memory without passing through MMU

  $emu->ram( $from, $to );

=cut

sub ram {
        my $self = shift;
        my ($from,$to) = @_;
        warn "ram($from,$to)\n";
        if ($from + $to) {
                printf "ram %04x - %04x\n", $from, $to;
                return @mem[$from .. $to - 1];
        }
        printf "ram %04x\n", $from;
        return $mem[$from] if defined($from);
        confess "no from address";
}

1;
1	package M6502;
2
3	use strict;
4	use warnings;
5
6	use Data::Dump qw/dump/;
7	use Carp qw/confess/;
8	use Exporter 'import';
9	our @EXPORT = qw'@mem $PC $A $P $X $Y $S $IPeriod';
10
11	=head1 NAME
12
13	M6502 - perl bindings for 6502 emulator
14
15	=cut
16
17	my $debug = 1;
18
19	our $VERSION = qw(0.0.1);
20
21	our @mem = (0xff) x 0x10000; # 64M
22
23	# program counter
24	our $PC = 0xbeef;
25	# CPU registars
26	our ( $A, $P, $X, $Y, $S ) = (0x42) x 5;
27	# Set IPeriod to number of CPU cycles between calls to Loop6502
28	our $IPeriod = 1;
29
30	=head1 init
31
32	Called before C<Run6502>
33
34	=cut
35
36	sub init {
37	my $self = shift;
38	warn dump(@_);
39	warn "inside init low-level M6502 from $self\n";
40	};
41
42	=head2 read
43
44	Read from memory
45
46	$byte = read( $address );
47
48	=cut
49
50	sub read {
51	my ($addr) = @_;
52	my $byte = $mem[$addr];
53	warn "# read(",dump(@_),") = ",dump( $byte ),"\n" if $debug;
54	return $byte;
55	}
56
57	=head2 write
58
59	Write into emory
60
61	write( $address, $byte );
62
63	=cut
64
65	sub write {
66	warn "# write(",dump(@_),")\n" if $debug;
67	my ($addr,$byte) = @_;
68	$mem[$addr] = $byte;
69	}
70
71	=head2 poke_code
72
73	Write series of bytes into memory without passing through MMU
74
75	$emu->poke_code( 0xbeef, 0xff, 0x00, 0xff, 0x00, 0xaa );
76
77	=cut
78
79	sub poke_code {
80	my $self = shift;
81	my $addr = shift;
82	warn sprintf("# poke_code(%04x,%s)\n", $addr, dump( @_ )) if $self->debug;
83	$mem[$addr++] = $_ foreach @_;
84	}
85
86	=head2 write_chunk
87
88	$emu->write_chunk( $address, $chunk_of_data );
89
90	=cut
91
92	sub write_chunk {
93	my ($self, $addr, $chunk) = @_;
94	my $len = length($chunk);
95	splice @mem, $addr, $len, unpack('C*', $chunk);
96	}
97
98	=head2 ram
99
100	Read searies of bytes from memory without passing through MMU
101
102	$emu->ram( $from, $to );
103
104	=cut
105
106	sub ram {
107	my $self = shift;
108	my ($from,$to) = @_;
109	warn "ram($from,$to)\n";
110	if ($from + $to) {
111	printf "ram %04x - %04x\n", $from, $to;
112	return @mem[$from .. $to - 1];
113	}
114	printf "ram %04x\n", $from;
115	return $mem[$from] if defined($from);
116	confess "no from address";
117	}
118
119	1;