CPU::Emulator::6502::Op::BIT - Bit test

Games-NES-Emulator documentation Contained in the Games-NES-Emulator distribution.

Index

Code Index:

NAME

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CPU::Emulator::6502::Op::BIT - Bit test

SYNOPSIS

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DESCRIPTION

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METHODS

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zero_page( )

absolute( )

bit( $addr )

Bit test with $addr.

AUTHOR

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Brian Cassidy <bricas@cpan.org>

COPYRIGHT AND LICENSE

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Copyright 2007 by Brian Cassidy

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

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* CPU::Emulator::6502
Games-NES-Emulator documentation Contained in the Games-NES-Emulator distribution. 
package CPU::Emulator::6502::Op::BIT;

use strict;
use warnings;

use constant INSTRUCTIONS => {
    0x24 => {
        addressing => 'zero_page',
        cycles => 3,
        code => \&bit,
    },
    0x2C => {
        addressing => 'absolute',
        cycles => 4,
        code => \&bit,
    },
};


sub bit {
    my $self = shift;
    my $reg = $self->registers;

    my $temp = $self->RAM_read( shift );

    $reg->{ status } &= CPU::Emulator::6502::CLEAR_SOZ;
    $self->set_nz( $temp );
    $reg->{ status } |= CPU::Emulator::6502::SET_OVERFLOW if $temp & 0x40;
}


1;