C166/ST10 Cross-Assembler, Linker/Locator, Utilities ... - Tasking

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Software Concept 1−15
All attributes of a task (except the task name to which no address or value
corresponds) are relocatable; a task can, therefore, be programmed as an
unit available for general use. It is not until locate−time that a task is
assigned, via its attributes, to the processor resources (internal RAM,
interrupt vector table). For special programming tasks, however, it is
possible to absolutely define the attributes already in the assembler. The
submodules of a task contain procedures which are, in general, used only
in this task. Each submodule contains a register bank declaration. This
declaration (REGBANK without name) notifies the assembler as to the
register configuration of the register bank defined in the main module. In
this manner, you can check already at assembly time whether only
registers belonging to this task have been used. If more registers have
been used, the linker issues a warning and expands the register bank to
the correct length.
Example:
Register definition in the main module:
RBAST1 REGBANK R0 − R9
Register declaration in the submodules:
REGBANK R0 − R9
All modules of a task are linked by the linker to a larger relocatable ’task
module’. Thus after the linker run, only one module exists for each task.
The locator fulfills the function of linking several tasks, distributing the
processor resources and generating one program module from all input
modules.
1.4.4 CONNECTIONS BETWEEN TASKS
Several tasks can communicate with each other by using shared data.
Access can also be made from one task to the data and code of another
task by COMMON sections. Fast access to data can be performed by
COMREG registers.