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 in humanly readable form

  my $dump = dump_R;

=cut

sub dump_R {
        my $dump = sprintf(" PC: %04x A:%02x P:%02x X:%02x Y:%02x S:%02x\n", $PC, $A, $P, $X, $Y, $S);
        warn "## M6502::dump_R $dump" if $debug;
        return $dump;
}

=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	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	50	our @EXPORT = qw'@mem $PC $A $P $X $Y $S $IPeriod $run_for $debug';
10	dpavlin	27
11	dpavlin	29	=head1 NAME
12	dpavlin	24
13	dpavlin	54	M6502 - perl bindings for M6502 CPU emulator
14	dpavlin	29
15			=cut
16
17	dpavlin	50	my $debug = 0;
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	54	=head1 FUNCTIONS
33	dpavlin	26
34	dpavlin	54	=head2 init
35
36	dpavlin	26	Called before C<Run6502>
37
38			=cut
39
40			sub init {
41	dpavlin	33	my $self = shift;
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	dpavlin	50	warn "## M6502::read(",dump(@_),") = ",dump( $byte ),"\n" if $debug;
57	dpavlin	27	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	dpavlin	50	warn "## M6502::write(",dump(@_),")\n" if $debug;
70	dpavlin	27	my ($addr,$byte) = @_;
71			$mem[$addr] = $byte;
72			}
73	dpavlin	29
74			=head2 poke_code
75
76	dpavlin	42	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	dpavlin	29
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	dpavlin	50	warn sprintf("## M6502::poke_code(%04x,%s)\n", $addr, dump( @_ )) if $self->debug;
87	dpavlin	42	#$mem[$addr++] = $_ foreach @_;
88	dpavlin	51	# call low-level write
89			Arch::write($addr++, $_) foreach @_;
90	dpavlin	29	}
91
92	dpavlin	51	=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	dpavlin	31	=head2 write_chunk
108
109	dpavlin	42	Low-level update of memory, overriding user specified MMU functions C<read> and C<write>
110
111	dpavlin	31	$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	dpavlin	42	=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	dpavlin	38	=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	dpavlin	50	warn "## M6502::push_R(",dump(@_),")\n" if $debug;
140	dpavlin	38	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	dpavlin	68	helper function which dumps registers in humanly readable form
149	dpavlin	38
150	dpavlin	68	my $dump = dump_R;
151
152	dpavlin	38	=cut
153
154			sub dump_R {
155	dpavlin	68	my $dump = sprintf(" PC: %04x A:%02x P:%02x X:%02x Y:%02x S:%02x\n", $PC, $A, $P, $X, $Y, $S);
156			warn "## M6502::dump_R $dump" if $debug;
157			return $dump;
158	dpavlin	38	}
159
160	dpavlin	55	=head1 SEE ALSO
161	dpavlin	54
162	dpavlin	55	L<Orao> is sample implementation using this module
163
164	dpavlin	54	=head1 AUTHOR
165
166			Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >>
167
168			=head1 COPYRIGHT & LICENSE
169
170			Copyright 2007 Dobrica Pavlinusic, All Rights Reserved.
171
172			This program is free software; you can redistribute it and/or modify it
173			under the same terms as Perl itself.
174
175			=cut
176	dpavlin	24	1;