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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 $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 6502 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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# Set IPeriod to number of CPU cycles between calls to Loop6502 |
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our $IPeriod = 1; |
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# Exec6502 cycles |
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our $run_for = 0; |
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|
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=head1 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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my ( $a, $p, $x, $y, $s, $pc ) = @_; |
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$PC = $pc; |
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$S=$s; $X=$x; $Y=$y; $P=$p; $A=$a; |
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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 |
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|
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=cut |
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|
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sub dump_R { |
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warn sprintf("## M6502::dump_R PC: %04x A:%02x P:%02x X:%02x Y:%02x S:%02x\n", $PC, $A, $P, $X, $Y, $S) if $debug; |
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} |
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|
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1; |
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