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 = 0;

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

=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 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 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 "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	dpavlin	42	our $run_for = 0;
31	dpavlin	24
32	dpavlin	26	=head1 init
33
34			Called before C<Run6502>
35
36			=cut
37
38			sub init {
39	dpavlin	33	my $self = shift;
40			warn dump(@_);
41			warn "inside init low-level M6502 from $self\n";
42	dpavlin	26	};
43	dpavlin	27
44			=head2 read
45
46			Read from memory
47
48			$byte = read( $address );
49
50			=cut
51
52			sub read {
53			my ($addr) = @_;
54			my $byte = $mem[$addr];
55			warn "# read(",dump(@_),") = ",dump( $byte ),"\n" if $debug;
56			return $byte;
57			}
58
59			=head2 write
60
61			Write into emory
62
63			write( $address, $byte );
64
65			=cut
66
67			sub write {
68			warn "# write(",dump(@_),")\n" if $debug;
69			my ($addr,$byte) = @_;
70			$mem[$addr] = $byte;
71			}
72	dpavlin	29
73			=head2 poke_code
74
75	dpavlin	42	Write series of bytes into memory passing through MMU (C<read> and C<write>)
76			functions. If you don't want to trigger MMU, use C<write_chunk>.
77	dpavlin	29
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 $self->debug;
86	dpavlin	42	#$mem[$addr++] = $_ foreach @_;
87			$self->write($addr++, $_) foreach @_;
88	dpavlin	29	}
89
90	dpavlin	31	=head2 write_chunk
91
92	dpavlin	42	Low-level update of memory, overriding user specified MMU functions C<read> and C<write>
93
94	dpavlin	31	$emu->write_chunk( $address, $chunk_of_data );
95
96			=cut
97
98			sub write_chunk {
99			my ($self, $addr, $chunk) = @_;
100			my $len = length($chunk);
101			splice @mem, $addr, $len, unpack('C*', $chunk);
102			}
103
104	dpavlin	29	=head2 ram
105
106			Read searies of bytes from memory without passing through MMU
107
108			$emu->ram( $from, $to );
109
110			=cut
111
112			sub ram {
113			my $self = shift;
114			my ($from,$to) = @_;
115	dpavlin	35	warn "ram($from,$to)\n";
116	dpavlin	29	if ($from + $to) {
117	dpavlin	30	printf "ram %04x - %04x\n", $from, $to;
118	dpavlin	35	return @mem[$from .. $to - 1];
119	dpavlin	29	}
120	dpavlin	30	printf "ram %04x\n", $from;
121	dpavlin	29	return $mem[$from] if defined($from);
122			confess "no from address";
123			}
124
125	dpavlin	42	=head2 prompt
126
127			Call this after C<< $run_for >> cycles have been run on processor
128
129			=cut
130
131			sub prompt {
132			warn "prompt -- you should override this\n";
133			return 1;
134			}
135
136	dpavlin	38	=head2 push_R
137
138			called by C<perl.c> to push changes in registars back to perl variables
139
140			=cut
141
142			sub push_R {
143			warn "push_R(",dump(@_),")\n";
144			my ( $a, $p, $x, $y, $s, $pc ) = @_;
145			$PC = $pc;
146			$S=$s; $X=$x; $Y=$y; $P=$p; $A=$a;
147			dump_R();
148			}
149
150			=head2 dump_R
151
152			helper function which dumps registers
153
154			=cut
155
156			sub dump_R {
157			warn sprintf("PC: %04x A:%02x P:%02x X:%02x Y:%02x S:%02x\n", $PC, $A, $P, $X, $Y, $S);
158			}
159
160	dpavlin	24	1;