Embedded Software for SoC - Grupo de Mecatrônica EESC/USP

RTOS Modeling for System Level Design 63
4.2.2. Synchronization refinement
In the specification model‚ all synchronization in the application or inside
communication channels is implemented using SLDL events. Synchronization
refinement wraps corresponding event handling routines of the RTOS model
around the event-related primitives (Figure 5-7). Each wait statement in the
code is enclosed in a pair of enter_wait / wakeup_wait calls to notify the RTOS
model about corresponding task state changes. Note that there is no need to
refine notify primitives as the state of the calling task is not influenced by
those calls.
After model refinement‚ both task management and synchronization are
implemented using the system calls of the RTOS model. Thus‚ the dynamic
system behavior is completely controlled by the RTOS model layer.
4.3. Implementation
The RTOS model library is implemented in approximately 2000 lines of SpecC
channel code [16]. The library contains models for different scheduling strategies
typically found in RTOS implementations‚ e.g. round-robin or prioritybased
scheduling [14]. In addition‚ the models are parametrizable in terms of
task parameters‚ preemption‚ and so on.
Task management in the RTOS models is implemented in a customary