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	dpavlin	24	package M6502;
2
3			use strict;
4			use warnings;
5
6	dpavlin	27	use Data::Dump qw/dump/;
7	dpavlin	29	use Carp qw/confess/;
8	dpavlin	34	use Exporter 'import';
9	dpavlin	40	our @EXPORT = qw'@mem $PC $A $P $X $Y $S $IPeriod $run_for';
10	dpavlin	27
11	dpavlin	29	=head1 NAME
12	dpavlin	24
13	dpavlin	29	M6502 - perl bindings for 6502 emulator
14
15			=cut
16
17	dpavlin	27	my $debug = 1;
18	dpavlin	24
19	dpavlin	29	our $VERSION = qw(0.0.1);
20	dpavlin	27
21	dpavlin	29	our @mem = (0xff) x 0x10000; # 64M
22
23	dpavlin	25	# program counter
24	dpavlin	34	our $PC = 0xbeef;
25	dpavlin	25	# CPU registars
26	dpavlin	36	our ( $A, $P, $X, $Y, $S ) = (0) x 5;
27	dpavlin	25	# Set IPeriod to number of CPU cycles between calls to Loop6502
28	dpavlin	27	our $IPeriod = 1;
29	dpavlin	40	# Exec6502 cycles
30			our $run_for = 1;
31			$run_for = 0x42;
32	dpavlin	24
33	dpavlin	26	=head1 init
34
35			Called before C<Run6502>
36
37			=cut
38
39			sub init {
40	dpavlin	33	my $self = shift;
41			warn dump(@_);
42			warn "inside init low-level M6502 from $self\n";
43	dpavlin	26	};
44	dpavlin	27
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	dpavlin	29
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	dpavlin	31	=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	dpavlin	29	=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,$to) = @_;
112	dpavlin	35	warn "ram($from,$to)\n";
113	dpavlin	29	if ($from + $to) {
114	dpavlin	30	printf "ram %04x - %04x\n", $from, $to;
115	dpavlin	35	return @mem[$from .. $to - 1];
116	dpavlin	29	}
117	dpavlin	30	printf "ram %04x\n", $from;
118	dpavlin	29	return $mem[$from] if defined($from);
119			confess "no from address";
120			}
121
122	dpavlin	38	=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	dpavlin	24	1;