User manual

3.3 Initialization steps

When the structure of the communication contexts is available, it is time to present more

information about the component initialization process. The initialization steps are as

follows:

1. As soon as the CHARON core has finished processing the load command, it creates

the necessary internal structures representing the device and allocates resources for

both the chapi_in and the chapi_out communication context descriptors.

2. The communication context descriptors are all initialized with all zeros.

3. The CHARON core then creates all required private data structures and binds the

communication context to them properly initializing the context field of the chapi_in

communication context descriptor.

4. If the corresponding routines are supported, the CHARON core initializes the

get_license_no, encrypt_data_block, decrypt_data_block, add_config_option, debug_trace and

the log_message(_ex) fields of the chapi_in communication context descriptor, so that the

component initialization routine can use them.

5. As soon as the CHARON core assigns a value to the dll parameter, it loads the .DLL

module, if necessary, and calls the component initialization routine.

6. As soon as the component initialization routine returns, the value returned is checked

against zero. If the value is zero, then the CHARON core considers the initialization as

failed, releases all the so far allocated resources (if any), and reports an error.

Otherwise the CHARON core updates the context field of the chapi_out communication

context descriptor with this value and proceeds with the initialization.

3.4 Run-time execution contexts

The CHAPI is based on a multi-threaded software execution model. This means that

procedures defined by the CHAPI run in different threads. The CHAPI selects the CPU

emulator thread as a special execution context, so that all the procedures invoked in that

thread are invoked in the execution context synchronized to the CPU emulator thread.

The CHAPI restricts the use of certain procedures to the execution context in the following

way:

• All the procedures identified by entry points stored in the put_sst, put_irq, clear_irq, and

move_io_space fields of a chapi_in communication context descriptor shall be invoked in

the execution context synchronized to the CPU emulator thread.