GameBoy\Opcode::opcode45 PHP Method

    public static function opcode45(Core $core)
    {
        $L = $core->unsbtub(($core->registersHL & 0xff) - 1);
        $core->FZero = $L == 0;
        $core->FHalfCarry = ($L & 0xf) == 0xf;
        $core->FSubtract = true;
        $core->registersHL = ($core->registersHL & 0xff00) + $L;
    }