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 = '0.0.3';
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
tie @mem, 'M6502::TieMem';

# 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 2007-8 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

package M6502::TieMem;

use strict;
use warnings;
use Tie::Array;
use base qw(Tie::Array);

#
sub TIEARRAY {
        my $class = shift;
#       my $opt   = shift;
#       my $self  = { %$opt };
        my $self = {};
        bless($self, __PACKAGE__);
        return $self;
}

sub DESTROY {}

#
sub FETCH {
        my $self = shift;
        my $n    = shift;
        my $val = M6502::mem_peek( $n );
        warn sprintf("FETCH %04x = %02x\n", $n, $val);
        return $val;
}

#
sub FETCHSIZE {
        return 0xffff;
}

#
sub STORE {
        my $self = shift;
        my $n    = shift;
        my $val  = shift;
        if ( $n > 0xffff ) {
                warn "over 64k: $n\n";
                return;
        }
        M6502::mem_poke( $n, $val );
        warn sprintf("STORE %04x <- %02x\n",$n, $val);
        return $val;
}

#
sub STORESIZE {
        die('not allowed (yet)');
}

sub PUSH {
        die('not allowed (yet)');
}

sub POP {
        die('not allowed (yet)');
}

sub SHIFT {
        die('not allowed (yet)');
}

sub UNSHIFT {
        die('not allowed (yet)');
}

sub DELETE {
        my $self = shift;
        my $n    = shift;
        $self->STORE($n, 0);
}

sub EXISTS {
        my $self = shift;
        my $n    = shift;
        return 0 if $n > 0xffff;
        return 1;
}

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	203	our $VERSION = '0.0.3';
11	dpavlin	80	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	203	our @mem; # = (0xff) x 0x10000; # 64M
25			tie @mem, 'M6502::TieMem';
26	dpavlin	29
27	dpavlin	25	# program counter
28	dpavlin	34	our $PC = 0xbeef;
29	dpavlin	25	# CPU registars
30	dpavlin	36	our ( $A, $P, $X, $Y, $S ) = (0) x 5;
31	dpavlin	74
32			our $IPeriod=1; # Set IPeriod to number of CPU cycles between calls to Loop6502
33			our $ICount;
34			our $IRequest; # Set to the INT_IRQ when pending IRQ
35			our $IAutoReset; # Set to 1 to autom. reset IRequest
36			our $TrapBadOps=1; # Set to 1 to warn of illegal opcodes
37			our $Trap; # Set Trap to address to trace from
38			our $Trace; # Set Trace=1 to start tracing
39
40	dpavlin	54	=head2 init
41
42	dpavlin	89	Setup read and write memory hooks (to implement memory mapped devices)
43	dpavlin	26
44	dpavlin	89	$init->(
45			read => sub {
46			return $mem[$_[0]];
47			},
48			write => sub {
49			$mem[$_[0]] = $_[1];
50			},
51			);
52
53	dpavlin	26	=cut
54
55	dpavlin	89	our $_rw_hooks = {
56			read => sub {
57	dpavlin	94	warn sprintf("# callback read(%04x) not implemented\n", @_) if $debug;
58	dpavlin	89	return $mem[$_[0]];
59			},
60			write => sub {
61	dpavlin	92	warn sprintf("# callback write(%04x,%02x) not implemented", @_) if $debug;
62	dpavlin	89	$mem[$_[0]] = $_[1];
63			},
64			};
65
66	dpavlin	26	sub init {
67	dpavlin	33	my $self = shift;
68	dpavlin	89	my $args = {@_};
69			warn "inside init low-level M6502 from ",ref($self),"\n";
70	dpavlin	27
71	dpavlin	89	foreach my $p ( qw/read write/ ) {
72			confess "need $p argument as coderef" unless ( $args->{$p} && ref($args->{$p}) eq 'CODE' );
73			$_rw_hooks->{$p} = $args->{$p};
74			}
75	dpavlin	27
76	dpavlin	89	};
77	dpavlin	27
78	dpavlin	29	=head2 poke_code
79
80	dpavlin	42	Write series of bytes into memory passing through MMU (C<read> and C<write>)
81			functions. If you don't want to trigger MMU, use C<write_chunk>.
82	dpavlin	29
83			$emu->poke_code( 0xbeef, 0xff, 0x00, 0xff, 0x00, 0xaa );
84
85			=cut
86
87			sub poke_code {
88			my $self = shift;
89			my $addr = shift;
90	dpavlin	50	warn sprintf("## M6502::poke_code(%04x,%s)\n", $addr, dump( @_ )) if $self->debug;
91	dpavlin	42	#$mem[$addr++] = $_ foreach @_;
92	dpavlin	51	# call low-level write
93	dpavlin	90	$_rw_hooks->{write}->( $addr++, $_ ) foreach @_;
94	dpavlin	29	}
95
96	dpavlin	51	=head2 ram
97
98			Read series of bytes into memory without MMU interaction
99
100			my @code = $emu->ram( 0xc000, 0xc1000 );
101
102			=cut
103
104			sub ram {
105			my $self = shift;
106			my ( $from, $to ) = @_;
107			warn sprintf("## M6502::ram(%04x,%04x)\n", $from, $to) if $self->debug;
108			return @mem[ $from .. $to ];
109			}
110
111	dpavlin	31	=head2 write_chunk
112
113	dpavlin	42	Low-level update of memory, overriding user specified MMU functions C<read> and C<write>
114
115	dpavlin	31	$emu->write_chunk( $address, $chunk_of_data );
116
117			=cut
118
119			sub write_chunk {
120			my ($self, $addr, $chunk) = @_;
121			my $len = length($chunk);
122			splice @mem, $addr, $len, unpack('C*', $chunk);
123			}
124
125	dpavlin	89	=head1 XS Callbacks
126
127			This functions are called from C<M6502.xs>
128
129			=head2 _read
130
131			Read from memory C callback
132
133			$byte = M6502::_read( $address );
134
135			=cut
136
137			sub _read {
138			return $_rw_hooks->{read}->( @_ );
139			}
140
141			=head2 _write
142
143			Write into memory C callback
144
145			M6502:_write( $address, $byte );
146
147			=cut
148
149			sub _write {
150			return $_rw_hooks->{write}->( @_ );
151			}
152
153	dpavlin	87	=head2 _update_perl_R
154	dpavlin	38
155	dpavlin	87	called by C<M6502.xs> to push changes in registars back to perl variables
156	dpavlin	38
157			=cut
158
159	dpavlin	87	sub _update_perl_R {
160			warn "## M6502::update_perl_R(",dump(@_),")\n" if $debug;
161	dpavlin	74	( $A, $P, $X, $Y, $S, $PC, $IPeriod, $ICount, $IRequest, $IAutoReset, $TrapBadOps, $Trap, $Trace ) = @_;
162	dpavlin	38	dump_R();
163			}
164
165	dpavlin	94	=head1 XS
166
167			Following functions are implemented in C<M6502.xs> and exported to perl.
168
169			=head2 set_debug
170
171			M6502::set_debug( 0 );
172
173			=head2 get_debug
174
175			my $debug = M6502::set_debug();
176
177			=head2 reset
178
179			Reset 6502 CPU, reading PC from C<0xfffc>
180
181			M6502::reset();
182
183			=head2 update_C_R
184
185			Push perl notion of register values to CPU emulator
186
187			M6502::update_C_R();
188
189			=head2 update_perl_R
190
191			Update perl notion of register values
192
193			M6502::update_perl_R();
194
195			=head2 exec
196
197			Execute cpu for specified number of cycles
198
199			my $cycles_left = M6502::exec( $execute_cpu_cycles );
200
201			=head1 Helpers
202
203	dpavlin	38	=head2 dump_R
204
205	dpavlin	68	helper function which dumps registers in humanly readable form
206	dpavlin	38
207	dpavlin	68	my $dump = dump_R;
208
209	dpavlin	38	=cut
210
211			sub dump_R {
212	dpavlin	74	my $dump = sprintf(" PC: %04x A:%02x P:%02x X:%02x Y:%02x S:%02x "
213			. "IPeriod:%d ICount:%d IRequest:%02x IAutoReset:%02x TrapBadOps:%d Trap:%d Trace:%d"
214			. "\n",
215			$PC, $A, $P, $X, $Y, $S, $IPeriod, $ICount, $IRequest, $IAutoReset, $TrapBadOps, $Trap, $Trace,
216			);
217	dpavlin	68	warn "## M6502::dump_R $dump" if $debug;
218			return $dump;
219	dpavlin	38	}
220
221	dpavlin	87	=head2 debug
222
223			Turn perl and C-level debugging on/off
224
225			$emu->debug( 0 );
226			$emu->debug( 1 );
227			print $emu->debug;
228
229			=cut
230
231			sub debug {
232			my $self = shift;
233			my $value = shift;
234			if (defined($value)) {
235			$debug = M6502::set_debug($value);
236			} else {
237			$debug = M6502::get_debug();
238			}
239			return $debug;
240			}
241
242	dpavlin	55	=head1 SEE ALSO
243	dpavlin	54
244	dpavlin	55	L<Orao> is sample implementation using this module
245
246	dpavlin	54	=head1 AUTHOR
247
248			Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >>
249
250			=head1 COPYRIGHT & LICENSE
251
252	dpavlin	203	Copyright 2007-8 Dobrica Pavlinusic, All Rights Reserved.
253	dpavlin	54
254			This program is free software; you can redistribute it and/or modify it
255			under the same terms as Perl itself.
256
257			=cut
258	dpavlin	203
259			package M6502::TieMem;
260
261			use strict;
262			use warnings;
263			use Tie::Array;
264			use base qw(Tie::Array);
265
266			#
267			sub TIEARRAY {
268			my $class = shift;
269			# my $opt = shift;
270			# my $self = { %$opt };
271			my $self = {};
272			bless($self, __PACKAGE__);
273			return $self;
274			}
275
276			sub DESTROY {}
277
278			#
279			sub FETCH {
280			my $self = shift;
281			my $n = shift;
282			my $val = M6502::mem_peek( $n );
283			warn sprintf("FETCH %04x = %02x\n", $n, $val);
284			return $val;
285			}
286
287			#
288			sub FETCHSIZE {
289			return 0xffff;
290			}
291
292			#
293			sub STORE {
294			my $self = shift;
295			my $n = shift;
296			my $val = shift;
297			if ( $n > 0xffff ) {
298			warn "over 64k: $n\n";
299			return;
300			}
301			M6502::mem_poke( $n, $val );
302			warn sprintf("STORE %04x <- %02x\n",$n, $val);
303			return $val;
304			}
305
306			#
307			sub STORESIZE {
308			die('not allowed (yet)');
309			}
310
311			sub PUSH {
312			die('not allowed (yet)');
313			}
314
315			sub POP {
316			die('not allowed (yet)');
317			}
318
319			sub SHIFT {
320			die('not allowed (yet)');
321			}
322
323			sub UNSHIFT {
324			die('not allowed (yet)');
325			}
326
327			sub DELETE {
328			my $self = shift;
329			my $n = shift;
330			$self->STORE($n, 0);
331			}
332
333			sub EXISTS {
334			my $self = shift;
335			my $n = shift;
336			return 0 if $n > 0xffff;
337			return 1;
338			}
339
340	dpavlin	24	1;