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package M6502; |
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|
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use strict; |
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use warnings; |
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|
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use Data::Dump qw/dump/; |
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use Carp qw/confess/; |
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use Exporter 'import'; |
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our @EXPORT = qw'dump_R @mem $PC $A $P $X $Y $S $IPeriod $ICount $IRequest $IAutoReset $TrapBadOps $Trap $Trace $debug'; |
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our $VERSION = '0.0.3'; |
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require XSLoader; |
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XSLoader::load('M6502', $VERSION); |
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|
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=head1 NAME |
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|
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M6502 - perl bindings for M6502 CPU emulator |
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|
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=head1 FUNCTIONS |
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|
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=cut |
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|
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our $debug = 0; |
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|
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our @mem; # = (0xff) x 0x10000; # 64M |
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tie @mem, 'M6502::TieMem'; |
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|
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# program counter |
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our $PC = 0xbeef; |
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# CPU registars |
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our ( $A, $P, $X, $Y, $S ) = (0) x 5; |
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|
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our $IPeriod=1; # Set IPeriod to number of CPU cycles between calls to Loop6502 |
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our $ICount; |
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our $IRequest; # Set to the INT_IRQ when pending IRQ |
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our $IAutoReset; # Set to 1 to autom. reset IRequest |
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our $TrapBadOps=1; # Set to 1 to warn of illegal opcodes |
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our $Trap; # Set Trap to address to trace from |
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our $Trace; # Set Trace=1 to start tracing |
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|
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=head2 init |
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|
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Setup read and write memory hooks (to implement memory mapped devices) |
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|
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$init->( |
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read => sub { |
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return $mem[$_[0]]; |
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}, |
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write => sub { |
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$mem[$_[0]] = $_[1]; |
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}, |
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); |
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|
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=cut |
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|
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our $_rw_hooks = { |
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read => sub { |
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warn sprintf("# callback read(%04x) not implemented\n", @_) if $debug; |
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return $mem[$_[0]]; |
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}, |
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write => sub { |
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warn sprintf("# callback write(%04x,%02x) not implemented", @_) if $debug; |
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$mem[$_[0]] = $_[1]; |
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}, |
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}; |
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|
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sub init { |
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my $self = shift; |
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my $args = {@_}; |
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warn "inside init low-level M6502 from ",ref($self),"\n"; |
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|
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foreach my $p ( qw/read write/ ) { |
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confess "need $p argument as coderef" unless ( $args->{$p} && ref($args->{$p}) eq 'CODE' ); |
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$_rw_hooks->{$p} = $args->{$p}; |
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} |
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|
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}; |
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|
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=head2 poke_code |
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|
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Write series of bytes into memory passing through MMU (C<read> and C<write>) |
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functions. If you don't want to trigger MMU, use C<write_chunk>. |
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|
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$emu->poke_code( 0xbeef, 0xff, 0x00, 0xff, 0x00, 0xaa ); |
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|
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=cut |
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|
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sub poke_code { |
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my $self = shift; |
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my $addr = shift; |
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warn sprintf("## M6502::poke_code(%04x,%s)\n", $addr, dump( @_ )) if $self->debug; |
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#$mem[$addr++] = $_ foreach @_; |
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# call low-level write |
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$_rw_hooks->{write}->( $addr++, $_ ) foreach @_; |
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} |
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|
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=head2 ram |
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|
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Read series of bytes into memory without MMU interaction |
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|
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my @code = $emu->ram( 0xc000, 0xc1000 ); |
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|
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=cut |
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|
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sub ram { |
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my $self = shift; |
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my ( $from, $to ) = @_; |
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warn sprintf("## M6502::ram(%04x,%04x)\n", $from, $to) if $self->debug; |
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return @mem[ $from .. $to ]; |
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} |
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|
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=head2 write_chunk |
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|
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Low-level update of memory, overriding user specified MMU functions C<read> and C<write> |
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|
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$emu->write_chunk( $address, $chunk_of_data ); |
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|
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=cut |
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|
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sub write_chunk { |
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my ($self, $addr, $chunk) = @_; |
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my $len = length($chunk); |
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splice @mem, $addr, $len, unpack('C*', $chunk); |
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} |
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|
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=head1 XS Callbacks |
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|
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This functions are called from C<M6502.xs> |
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|
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=head2 _read |
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|
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Read from memory C callback |
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|
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$byte = M6502::_read( $address ); |
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|
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=cut |
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|
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sub _read { |
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return $_rw_hooks->{read}->( @_ ); |
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} |
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|
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=head2 _write |
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|
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Write into memory C callback |
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|
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M6502:_write( $address, $byte ); |
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|
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=cut |
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|
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sub _write { |
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return $_rw_hooks->{write}->( @_ ); |
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} |
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|
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=head2 _update_perl_R |
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|
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called by C<M6502.xs> to push changes in registars back to perl variables |
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|
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=cut |
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|
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sub _update_perl_R { |
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warn "## M6502::update_perl_R(",dump(@_),")\n" if $debug; |
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( $A, $P, $X, $Y, $S, $PC, $IPeriod, $ICount, $IRequest, $IAutoReset, $TrapBadOps, $Trap, $Trace ) = @_; |
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dump_R(); |
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} |
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|
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=head1 XS |
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|
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Following functions are implemented in C<M6502.xs> and exported to perl. |
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|
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=head2 set_debug |
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|
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M6502::set_debug( 0 ); |
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|
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=head2 get_debug |
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|
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my $debug = M6502::set_debug(); |
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|
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=head2 reset |
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|
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Reset 6502 CPU, reading PC from C<0xfffc> |
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|
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M6502::reset(); |
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|
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=head2 update_C_R |
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|
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Push perl notion of register values to CPU emulator |
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|
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M6502::update_C_R(); |
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|
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=head2 update_perl_R |
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|
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Update perl notion of register values |
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|
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M6502::update_perl_R(); |
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|
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=head2 exec |
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|
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Execute cpu for specified number of cycles |
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|
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my $cycles_left = M6502::exec( $execute_cpu_cycles ); |
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|
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=head1 Helpers |
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|
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=head2 dump_R |
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|
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helper function which dumps registers in humanly readable form |
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|
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my $dump = dump_R; |
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|
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=cut |
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|
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sub dump_R { |
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my $dump = sprintf(" PC: %04x A:%02x P:%02x X:%02x Y:%02x S:%02x " |
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. "IPeriod:%d ICount:%d IRequest:%02x IAutoReset:%02x TrapBadOps:%d Trap:%d Trace:%d" |
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. "\n", |
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$PC, $A, $P, $X, $Y, $S, $IPeriod, $ICount, $IRequest, $IAutoReset, $TrapBadOps, $Trap, $Trace, |
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); |
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warn "## M6502::dump_R $dump" if $debug; |
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return $dump; |
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} |
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|
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=head2 debug |
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|
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Turn perl and C-level debugging on/off |
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|
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$emu->debug( 0 ); |
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$emu->debug( 1 ); |
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print $emu->debug; |
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|
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=cut |
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|
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sub debug { |
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my $self = shift; |
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my $value = shift; |
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if (defined($value)) { |
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$debug = M6502::set_debug($value); |
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} else { |
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$debug = M6502::get_debug(); |
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} |
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return $debug; |
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} |
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|
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=head1 SEE ALSO |
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|
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L<Orao> is sample implementation using this module |
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|
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=head1 AUTHOR |
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|
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Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >> |
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|
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=head1 COPYRIGHT & LICENSE |
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|
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Copyright 2007-8 Dobrica Pavlinusic, All Rights Reserved. |
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|
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This program is free software; you can redistribute it and/or modify it |
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under the same terms as Perl itself. |
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|
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=cut |
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|
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package M6502::TieMem; |
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|
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use strict; |
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use warnings; |
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use Tie::Array; |
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use base qw(Tie::Array); |
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|
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# |
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sub TIEARRAY { |
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my $class = shift; |
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# my $opt = shift; |
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# my $self = { %$opt }; |
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my $self = {}; |
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bless($self, __PACKAGE__); |
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return $self; |
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} |
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|
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sub DESTROY {} |
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|
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# |
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sub FETCH { |
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my $self = shift; |
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my $n = shift; |
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my $val = M6502::mem_peek( $n ); |
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warn sprintf("FETCH %04x = %02x\n", $n, $val); |
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return $val; |
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} |
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|
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# |
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sub FETCHSIZE { |
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return 0xffff; |
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} |
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|
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# |
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sub STORE { |
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my $self = shift; |
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my $n = shift; |
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my $val = shift; |
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if ( $n > 0xffff ) { |
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warn "over 64k: $n\n"; |
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return; |
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} |
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M6502::mem_poke( $n, $val ); |
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warn sprintf("STORE %04x <- %02x\n",$n, $val); |
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return $val; |
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} |
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|
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# |
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sub STORESIZE { |
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die('not allowed (yet)'); |
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} |
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|
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sub PUSH { |
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die('not allowed (yet)'); |
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} |
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|
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sub POP { |
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die('not allowed (yet)'); |
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} |
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|
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sub SHIFT { |
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die('not allowed (yet)'); |
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} |
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|
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sub UNSHIFT { |
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die('not allowed (yet)'); |
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} |
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|
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sub DELETE { |
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my $self = shift; |
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my $n = shift; |
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$self->STORE($n, 0); |
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} |
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|
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sub EXISTS { |
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my $self = shift; |
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my $n = shift; |
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return 0 if $n > 0xffff; |
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return 1; |
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} |
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|
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