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 $debug';

=head1 NAME

M6502 - perl bindings for M6502 CPU 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 = 1;
# Exec6502 cycles
our $run_for = 0;

=head1 FUNCTIONS

=head2 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;
}

=head1 SEE ALSO

L<Orao> is sample implementation using this module

=head1 AUTHOR

Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >>

=head1 COPYRIGHT & LICENSE

Copyright 2007 Dobrica Pavlinusic, All Rights Reserved.

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

=cut
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 $debug';
10
11	=head1 NAME
12
13	M6502 - perl bindings for M6502 CPU emulator
14
15	=cut
16
17	my $debug = 0;
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 = 0;
31
32	=head1 FUNCTIONS
33
34	=head2 init
35
36	Called before C<Run6502>
37
38	=cut
39
40	sub init {
41	my $self = shift;
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 "## M6502::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 "## M6502::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 passing through MMU (C<read> and C<write>)
77	functions. If you don't want to trigger MMU, use C<write_chunk>.
78
79	$emu->poke_code( 0xbeef, 0xff, 0x00, 0xff, 0x00, 0xaa );
80
81	=cut
82
83	sub poke_code {
84	my $self = shift;
85	my $addr = shift;
86	warn sprintf("## M6502::poke_code(%04x,%s)\n", $addr, dump( @_ )) if $self->debug;
87	#$mem[$addr++] = $_ foreach @_;
88	# call low-level write
89	Arch::write($addr++, $_) foreach @_;
90	}
91
92	=head2 ram
93
94	Read series of bytes into memory without MMU interaction
95
96	my @code = $emu->ram( 0xc000, 0xc1000 );
97
98	=cut
99
100	sub ram {
101	my $self = shift;
102	my ( $from, $to ) = @_;
103	warn sprintf("## M6502::ram(%04x,%04x)\n", $from, $to) if $self->debug;
104	return @mem[ $from .. $to ];
105	}
106
107	=head2 write_chunk
108
109	Low-level update of memory, overriding user specified MMU functions C<read> and C<write>
110
111	$emu->write_chunk( $address, $chunk_of_data );
112
113	=cut
114
115	sub write_chunk {
116	my ($self, $addr, $chunk) = @_;
117	my $len = length($chunk);
118	splice @mem, $addr, $len, unpack('C*', $chunk);
119	}
120
121	=head2 prompt
122
123	Call this after C<< $run_for >> cycles have been run on processor
124
125	=cut
126
127	sub prompt {
128	warn "prompt -- you should override this\n";
129	return 1;
130	}
131
132	=head2 push_R
133
134	called by C<perl.c> to push changes in registars back to perl variables
135
136	=cut
137
138	sub push_R {
139	warn "## M6502::push_R(",dump(@_),")\n" if $debug;
140	my ( $a, $p, $x, $y, $s, $pc ) = @_;
141	$PC = $pc;
142	$S=$s; $X=$x; $Y=$y; $P=$p; $A=$a;
143	dump_R();
144	}
145
146	=head2 dump_R
147
148	helper function which dumps registers
149
150	=cut
151
152	sub dump_R {
153	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;
154	}
155
156	=head1 SEE ALSO
157
158	L<Orao> is sample implementation using this module
159
160	=head1 AUTHOR
161
162	Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >>
163
164	=head1 COPYRIGHT & LICENSE
165
166	Copyright 2007 Dobrica Pavlinusic, All Rights Reserved.
167
168	This program is free software; you can redistribute it and/or modify it
169	under the same terms as Perl itself.
170
171	=cut
172	1;