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'dump_R @mem $PC $A $P $X $Y $S $IPeriod $ICount $IRequest $IAutoReset $TrapBadOps $Trap $Trace $debug';
our $VERSION = '0.0.2';
require XSLoader;
XSLoader::load('M6502', $VERSION);

=head1 NAME

M6502 - perl bindings for M6502 CPU emulator

=head1 FUNCTIONS

=cut

our $debug = 0;

our @mem = (0xff) x 0x10000;    # 64M

# program counter
our $PC = 0xbeef;
# CPU registars
our ( $A, $P, $X, $Y, $S ) = (0) x 5;

our $IPeriod=1;         # Set IPeriod to number of CPU cycles between calls to Loop6502
our $ICount;
our $IRequest;          # Set to the INT_IRQ when pending IRQ
our $IAutoReset;        # Set to 1 to autom. reset IRequest
our $TrapBadOps=1;      # Set to 1 to warn of illegal opcodes
our $Trap;                      # Set Trap to address to trace from
our $Trace;                     # Set Trace=1 to start tracing

=head2 init

Setup read and write memory hooks (to implement memory mapped devices)

  $init->(
        read => sub {
                return $mem[$_[0]];
        },
        write => sub {
                $mem[$_[0]] = $_[1];
        },
  );

=cut

our $_rw_hooks = {
        read => sub {
                warn sprintf("# callback read(%04x) not implemented\n", @_) if $debug;
                return $mem[$_[0]];
        },
        write => sub {
                warn sprintf("# callback write(%04x,%02x) not implemented", @_) if $debug;
                $mem[$_[0]] = $_[1];
        },
};

sub init {
        my $self = shift;
        my $args = {@_};
        warn "inside init low-level M6502 from ",ref($self),"\n";

        foreach my $p ( qw/read write/ ) {
                confess "need $p argument as coderef" unless ( $args->{$p} && ref($args->{$p}) eq 'CODE' );
                $_rw_hooks->{$p} = $args->{$p};
        }

};

=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
        $_rw_hooks->{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);
}

=head1 XS Callbacks

This functions are called from C<M6502.xs>

=head2 _read

Read from memory C callback

  $byte = M6502::_read( $address );

=cut

sub _read {
        return $_rw_hooks->{read}->( @_ );
}

=head2 _write

Write into memory C callback

  M6502:_write( $address, $byte );

=cut

sub _write {
        return $_rw_hooks->{write}->( @_ );
}

=head2 _update_perl_R

called by C<M6502.xs> to push changes in registars back to perl variables

=cut

sub _update_perl_R {
        warn "## M6502::update_perl_R(",dump(@_),")\n" if $debug;
        ( $A, $P, $X, $Y, $S, $PC, $IPeriod, $ICount, $IRequest, $IAutoReset, $TrapBadOps, $Trap, $Trace ) = @_;
        dump_R();
}

=head1 XS

Following functions are implemented in C<M6502.xs> and exported to perl.

=head2 set_debug

  M6502::set_debug( 0 );

=head2 get_debug

  my $debug = M6502::set_debug();

=head2 reset

Reset 6502 CPU, reading PC from C<0xfffc>

  M6502::reset();

=head2 update_C_R

Push perl notion of register values to CPU emulator

  M6502::update_C_R();

=head2 update_perl_R

Update perl notion of register values

  M6502::update_perl_R();

=head2 exec

Execute cpu for specified number of cycles

  my $cycles_left = M6502::exec( $execute_cpu_cycles );

=head1 Helpers

=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 "
                . "IPeriod:%d ICount:%d IRequest:%02x IAutoReset:%02x TrapBadOps:%d Trap:%d Trace:%d"
                . "\n",
                $PC, $A, $P, $X, $Y, $S, $IPeriod, $ICount, $IRequest, $IAutoReset, $TrapBadOps, $Trap, $Trace,
        );
        warn "## M6502::dump_R $dump" if $debug;
        return $dump;
}

=head2 debug

Turn perl and C-level debugging on/off

  $emu->debug( 0 );
  $emu->debug( 1 );
  print $emu->debug;

=cut

sub debug {
        my $self = shift;
        my $value = shift;
        if (defined($value)) {
                $debug = M6502::set_debug($value);
        } else {
                $debug = M6502::get_debug();
        }
        return $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	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	96	our @EXPORT = qw'dump_R @mem $PC $A $P $X $Y $S $IPeriod $ICount $IRequest $IAutoReset $TrapBadOps $Trap $Trace $debug';
10	dpavlin	80	our $VERSION = '0.0.2';
11			require XSLoader;
12			XSLoader::load('M6502', $VERSION);
13	dpavlin	27
14	dpavlin	29	=head1 NAME
15	dpavlin	24
16	dpavlin	54	M6502 - perl bindings for M6502 CPU emulator
17	dpavlin	29
18	dpavlin	89	=head1 FUNCTIONS
19
20	dpavlin	29	=cut
21
22	dpavlin	87	our $debug = 0;
23	dpavlin	24
24	dpavlin	29	our @mem = (0xff) x 0x10000; # 64M
25
26	dpavlin	25	# program counter
27	dpavlin	34	our $PC = 0xbeef;
28	dpavlin	25	# CPU registars
29	dpavlin	36	our ( $A, $P, $X, $Y, $S ) = (0) x 5;
30	dpavlin	74
31			our $IPeriod=1; # Set IPeriod to number of CPU cycles between calls to Loop6502
32			our $ICount;
33			our $IRequest; # Set to the INT_IRQ when pending IRQ
34			our $IAutoReset; # Set to 1 to autom. reset IRequest
35			our $TrapBadOps=1; # Set to 1 to warn of illegal opcodes
36			our $Trap; # Set Trap to address to trace from
37			our $Trace; # Set Trace=1 to start tracing
38
39	dpavlin	54	=head2 init
40
41	dpavlin	89	Setup read and write memory hooks (to implement memory mapped devices)
42	dpavlin	26
43	dpavlin	89	$init->(
44			read => sub {
45			return $mem[$_[0]];
46			},
47			write => sub {
48			$mem[$_[0]] = $_[1];
49			},
50			);
51
52	dpavlin	26	=cut
53
54	dpavlin	89	our $_rw_hooks = {
55			read => sub {
56	dpavlin	94	warn sprintf("# callback read(%04x) not implemented\n", @_) if $debug;
57	dpavlin	89	return $mem[$_[0]];
58			},
59			write => sub {
60	dpavlin	92	warn sprintf("# callback write(%04x,%02x) not implemented", @_) if $debug;
61	dpavlin	89	$mem[$_[0]] = $_[1];
62			},
63			};
64
65	dpavlin	26	sub init {
66	dpavlin	33	my $self = shift;
67	dpavlin	89	my $args = {@_};
68			warn "inside init low-level M6502 from ",ref($self),"\n";
69	dpavlin	27
70	dpavlin	89	foreach my $p ( qw/read write/ ) {
71			confess "need $p argument as coderef" unless ( $args->{$p} && ref($args->{$p}) eq 'CODE' );
72			$_rw_hooks->{$p} = $args->{$p};
73			}
74	dpavlin	27
75	dpavlin	89	};
76	dpavlin	27
77	dpavlin	29	=head2 poke_code
78
79	dpavlin	42	Write series of bytes into memory passing through MMU (C<read> and C<write>)
80			functions. If you don't want to trigger MMU, use C<write_chunk>.
81	dpavlin	29
82			$emu->poke_code( 0xbeef, 0xff, 0x00, 0xff, 0x00, 0xaa );
83
84			=cut
85
86			sub poke_code {
87			my $self = shift;
88			my $addr = shift;
89	dpavlin	50	warn sprintf("## M6502::poke_code(%04x,%s)\n", $addr, dump( @_ )) if $self->debug;
90	dpavlin	42	#$mem[$addr++] = $_ foreach @_;
91	dpavlin	51	# call low-level write
92	dpavlin	90	$_rw_hooks->{write}->( $addr++, $_ ) foreach @_;
93	dpavlin	29	}
94
95	dpavlin	51	=head2 ram
96
97			Read series of bytes into memory without MMU interaction
98
99			my @code = $emu->ram( 0xc000, 0xc1000 );
100
101			=cut
102
103			sub ram {
104			my $self = shift;
105			my ( $from, $to ) = @_;
106			warn sprintf("## M6502::ram(%04x,%04x)\n", $from, $to) if $self->debug;
107			return @mem[ $from .. $to ];
108			}
109
110	dpavlin	31	=head2 write_chunk
111
112	dpavlin	42	Low-level update of memory, overriding user specified MMU functions C<read> and C<write>
113
114	dpavlin	31	$emu->write_chunk( $address, $chunk_of_data );
115
116			=cut
117
118			sub write_chunk {
119			my ($self, $addr, $chunk) = @_;
120			my $len = length($chunk);
121			splice @mem, $addr, $len, unpack('C*', $chunk);
122			}
123
124	dpavlin	89	=head1 XS Callbacks
125
126			This functions are called from C<M6502.xs>
127
128			=head2 _read
129
130			Read from memory C callback
131
132			$byte = M6502::_read( $address );
133
134			=cut
135
136			sub _read {
137			return $_rw_hooks->{read}->( @_ );
138			}
139
140			=head2 _write
141
142			Write into memory C callback
143
144			M6502:_write( $address, $byte );
145
146			=cut
147
148			sub _write {
149			return $_rw_hooks->{write}->( @_ );
150			}
151
152	dpavlin	87	=head2 _update_perl_R
153	dpavlin	38
154	dpavlin	87	called by C<M6502.xs> to push changes in registars back to perl variables
155	dpavlin	38
156			=cut
157
158	dpavlin	87	sub _update_perl_R {
159			warn "## M6502::update_perl_R(",dump(@_),")\n" if $debug;
160	dpavlin	74	( $A, $P, $X, $Y, $S, $PC, $IPeriod, $ICount, $IRequest, $IAutoReset, $TrapBadOps, $Trap, $Trace ) = @_;
161	dpavlin	38	dump_R();
162			}
163
164	dpavlin	94	=head1 XS
165
166			Following functions are implemented in C<M6502.xs> and exported to perl.
167
168			=head2 set_debug
169
170			M6502::set_debug( 0 );
171
172			=head2 get_debug
173
174			my $debug = M6502::set_debug();
175
176			=head2 reset
177
178			Reset 6502 CPU, reading PC from C<0xfffc>
179
180			M6502::reset();
181
182			=head2 update_C_R
183
184			Push perl notion of register values to CPU emulator
185
186			M6502::update_C_R();
187
188			=head2 update_perl_R
189
190			Update perl notion of register values
191
192			M6502::update_perl_R();
193
194			=head2 exec
195
196			Execute cpu for specified number of cycles
197
198			my $cycles_left = M6502::exec( $execute_cpu_cycles );
199
200			=head1 Helpers
201
202	dpavlin	38	=head2 dump_R
203
204	dpavlin	68	helper function which dumps registers in humanly readable form
205	dpavlin	38
206	dpavlin	68	my $dump = dump_R;
207
208	dpavlin	38	=cut
209
210			sub dump_R {
211	dpavlin	74	my $dump = sprintf(" PC: %04x A:%02x P:%02x X:%02x Y:%02x S:%02x "
212			. "IPeriod:%d ICount:%d IRequest:%02x IAutoReset:%02x TrapBadOps:%d Trap:%d Trace:%d"
213			. "\n",
214			$PC, $A, $P, $X, $Y, $S, $IPeriod, $ICount, $IRequest, $IAutoReset, $TrapBadOps, $Trap, $Trace,
215			);
216	dpavlin	68	warn "## M6502::dump_R $dump" if $debug;
217			return $dump;
218	dpavlin	38	}
219
220	dpavlin	87	=head2 debug
221
222			Turn perl and C-level debugging on/off
223
224			$emu->debug( 0 );
225			$emu->debug( 1 );
226			print $emu->debug;
227
228			=cut
229
230			sub debug {
231			my $self = shift;
232			my $value = shift;
233			if (defined($value)) {
234			$debug = M6502::set_debug($value);
235			} else {
236			$debug = M6502::get_debug();
237			}
238			return $debug;
239			}
240
241	dpavlin	55	=head1 SEE ALSO
242	dpavlin	54
243	dpavlin	55	L<Orao> is sample implementation using this module
244
245	dpavlin	54	=head1 AUTHOR
246
247			Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >>
248
249			=head1 COPYRIGHT & LICENSE
250
251			Copyright 2007 Dobrica Pavlinusic, All Rights Reserved.
252
253			This program is free software; you can redistribute it and/or modify it
254			under the same terms as Perl itself.
255
256			=cut
257	dpavlin	24	1;