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 $run_for';

=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 ) = (0) x 5;
# Set IPeriod to number of CPU cycles between calls to Loop6502
our $IPeriod = 1;
# Exec6502 cycles
our $run_for = 1;
$run_for = 0x42;

=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";
}

=head2 push_R

called by C<perl.c> to push changes in registars back to perl variables

=cut

sub push_R {
        warn "push_R(",dump(@_),")\n";
        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("PC: %04x A:%02x P:%02x X:%02x Y:%02x S:%02x\n", $PC, $A, $P, $X, $Y, $S);
}

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 $run_for';
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 ) = (0) x 5;
27	# Set IPeriod to number of CPU cycles between calls to Loop6502
28	our $IPeriod = 1;
29	# Exec6502 cycles
30	our $run_for = 1;
31	$run_for = 0x42;
32
33	=head1 init
34
35	Called before C<Run6502>
36
37	=cut
38
39	sub init {
40	my $self = shift;
41	warn dump(@_);
42	warn "inside init low-level M6502 from $self\n";
43	};
44
45	=head2 read
46
47	Read from memory
48
49	$byte = read( $address );
50
51	=cut
52
53	sub read {
54	my ($addr) = @_;
55	my $byte = $mem[$addr];
56	warn "# read(",dump(@_),") = ",dump( $byte ),"\n" if $debug;
57	return $byte;
58	}
59
60	=head2 write
61
62	Write into emory
63
64	write( $address, $byte );
65
66	=cut
67
68	sub write {
69	warn "# write(",dump(@_),")\n" if $debug;
70	my ($addr,$byte) = @_;
71	$mem[$addr] = $byte;
72	}
73
74	=head2 poke_code
75
76	Write series of bytes into memory without passing through MMU
77
78	$emu->poke_code( 0xbeef, 0xff, 0x00, 0xff, 0x00, 0xaa );
79
80	=cut
81
82	sub poke_code {
83	my $self = shift;
84	my $addr = shift;
85	warn sprintf("# poke_code(%04x,%s)\n", $addr, dump( @_ )) if $self->debug;
86	$mem[$addr++] = $_ foreach @_;
87	}
88
89	=head2 write_chunk
90
91	$emu->write_chunk( $address, $chunk_of_data );
92
93	=cut
94
95	sub write_chunk {
96	my ($self, $addr, $chunk) = @_;
97	my $len = length($chunk);
98	splice @mem, $addr, $len, unpack('C*', $chunk);
99	}
100
101	=head2 ram
102
103	Read searies of bytes from memory without passing through MMU
104
105	$emu->ram( $from, $to );
106
107	=cut
108
109	sub ram {
110	my $self = shift;
111	my ($from,$to) = @_;
112	warn "ram($from,$to)\n";
113	if ($from + $to) {
114	printf "ram %04x - %04x\n", $from, $to;
115	return @mem[$from .. $to - 1];
116	}
117	printf "ram %04x\n", $from;
118	return $mem[$from] if defined($from);
119	confess "no from address";
120	}
121
122	=head2 push_R
123
124	called by C<perl.c> to push changes in registars back to perl variables
125
126	=cut
127
128	sub push_R {
129	warn "push_R(",dump(@_),")\n";
130	my ( $a, $p, $x, $y, $s, $pc ) = @_;
131	$PC = $pc;
132	$S=$s; $X=$x; $Y=$y; $P=$p; $A=$a;
133	dump_R();
134	}
135
136	=head2 dump_R
137
138	helper function which dumps registers
139
140	=cut
141
142	sub dump_R {
143	warn sprintf("PC: %04x A:%02x P:%02x X:%02x Y:%02x S:%02x\n", $PC, $A, $P, $X, $Y, $S);
144	}
145
146	1;