= Task models =

A task model is a definition of an instanciable task, ie
 * a name
 * a list of ports accepting resources from different [wiki:DsxResource resource types]
 * a list of available implementations

{{{
TaskModel(
        'tg',
        ports = {'output': MwmrOutput(32)} )
}}}

= Task implementations =

== Software Task ==

A software task implementation is defined by:
 * a function to call
 * a list of C source files (even if some files are shared between tasks, you must redeclare them in each using task implementation definition)
 * a list of defines to be defined later (arg `defines = {}` on task instanciation) see PerTaskCflags

{{{
TaskModel(
        'tg',
        ports = {'output': MwmrOutput(32)},
        impl = [ SwTask( 'tg',
                         stack_size = 4096,
                         sources = [ 'src/tg_posix.c' ],
                         defines = ['FILE_NAME'] )
               ] )
}}}

== Hardware Task ==

An hardware implementation is in fact a corpocessor (which must be implemented in simulator/synthesis context and declared in DSX) doing the same thing as the task.

The following restrictions apply:
 * Task must only use MwMr fifos for data exchange
 * Task must not be RealTime

Declaration consists of:
 * Coprocessor reference
 * Optional coprocessor arguments

{{{
TaskModel(
        'tg',
        ports = {'output': MwmrOutput(32)},
        impl = [ SwTask( 'tg',
                         stack_size = 4096,
                         sources = [ 'src/tg_posix.c' ] )
                 HwTask( Tg, filename = 'plan.jpg' )
               ] )
}}}

== Virtual Task ==

If a task follows constraints for having an hardware implementation, it may be virtually implemented in hardware, which means it will be run in simulator's context as if it were a coprocessor, actually using C implementation.

This kind if virtualization is only available for SystemC simulation (ie not VHDL), and you must have defined a software implementation.
If your task has a SyntheticTask() declaration and an HwTask at the same time, the implementation chosen by DSX for simulation purposes will be unpredictable, you should avoid such situations.

{{{
TaskModel(
        'idct',
        ports = {'output': MwmrOutput(64),
                 'input': MwmrInput(256)},
        impl = [ SwTask( 'idct',
                         stack_size = 1024,
                         sources = [ 'src/idct.c' ] ),
                 SyntheticTask()
               ] )
}}}

== Task Synthesis ==

Using Ugh, a task may be synthetized, this is not supported at this time.