.. _prog_guide:

Programming Guide
=================

Programming models
------------------

The logical cores of an XCore multicore processor can be programmed in extremely
flexible ways:

"Hardware as Software"
  Individual logical cores, or collaborations thereof, can respond within a few
  clock cycles to specific hardware events. Once activated, each logical core is
  given a gauranteed share of the processor cycles. With this programming model,
  parts of the XCore can be thought of as software-defined hardware peripherals.
"Vector accelerator"
  Logical cores may act as a team operating on the same vector. This approach,
  combined with VPU acceleration, allows the greatest utilisation of the
  available compute.
"Application processor"
  As well as responding to events, logical cores can respond to interrupts. This
  allows a logical core to behave like a traditional MCU running an RTOS.

These application architecture approaches may be combined and may even be chosen
as appropriate at runtime. :ref:`prog_model` explores these concepts in more
depth.

Languages
---------

XCore processors are, in the main, programmed using the familiar C (or C++)
language with special hardware features being accessed through system libraries.
See :ref:`lib_xcore_prog_guide` for more details.

Where a particularly performant piece of code is required, a developer
might chose to program in assembly.

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.. toctree::
   :hidden:

   quick-start/index
   prog-ref/index