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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'@mem $PC $A $P $X $Y $S $IPeriod $ICount $IRequest $IAutoReset $TrapBadOps $Trap $Trace $run_for $debug'; |
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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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=cut |
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|
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my $debug = 0; |
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|
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our $VERSION = qw(0.0.1); |
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|
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our @mem = (0xff) x 0x10000; # 64M |
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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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# Exec6502 cycles |
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our $run_for = 0; |
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|
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=head1 FUNCTIONS |
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|
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=head2 init |
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|
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Called before C<Run6502> |
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|
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=cut |
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|
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sub init { |
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my $self = shift; |
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warn "inside init low-level M6502 from $self\n"; |
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}; |
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|
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=head2 read |
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|
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Read from memory |
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|
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$byte = read( $address ); |
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|
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=cut |
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|
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sub read { |
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my ($addr) = @_; |
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my $byte = $mem[$addr]; |
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warn "## M6502::read(",dump(@_),") = ",dump( $byte ),"\n" if $debug; |
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return $byte; |
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} |
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|
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=head2 write |
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|
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Write into emory |
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|
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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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warn "## M6502::write(",dump(@_),")\n" if $debug; |
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my ($addr,$byte) = @_; |
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$mem[$addr] = $byte; |
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} |
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|
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=head2 poke_code |
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|
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Write series of bytes into memory passing through MMU (C<read> and C<write>) |
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functions. If you don't want to trigger MMU, use C<write_chunk>. |
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|
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$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++] = $_ foreach @_; |
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# call low-level write |
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Arch::write($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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=head2 prompt |
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|
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Call this after C<< $run_for >> cycles have been run on processor |
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|
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=cut |
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|
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sub prompt { |
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warn "prompt -- you should override this\n"; |
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return 1; |
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} |
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|
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=head2 push_R |
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|
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called by C<perl.c> 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 push_R { |
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warn "## M6502::push_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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=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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=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 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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