gcc/doc/gcc/extensions-to-the-c-language-family/declaring-attributes-of-functions/microblaze-function-attributes.rst

   1 ..
   2   Copyright 1988-2022 Free Software Foundation, Inc.
   3   This is part of the GCC manual.
   4   For copying conditions, see the copyright.rst file.
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   6 .. _microblaze-function-attributes:
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   8 MicroBlaze Function Attributes
   9 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  10
  11 These function attributes are supported on MicroBlaze targets:
  12
  13 .. index:: save_volatiles function attribute, MicroBlaze
  14
  15 .. microblaze-fn-attr:: save_volatiles
  16
  17   Use this attribute to indicate that the function is
  18   an interrupt handler.  All volatile registers (in addition to non-volatile
  19   registers) are saved in the function prologue.  If the function is a leaf
  20   function, only volatiles used by the function are saved.  A normal function
  21   return is generated instead of a return from interrupt.
  22
  23 .. index:: break_handler function attribute, MicroBlaze, break handler functions
  24
  25 .. microblaze-fn-attr:: break_handler
  26
  27   Use this attribute to indicate that
  28   the specified function is a break handler.  The compiler generates function
  29   entry and exit sequences suitable for use in an break handler when this
  30   attribute is present. The return from :microblaze-fn-attr:`break_handler` is done through
  31   the ``rtbd`` instead of ``rtsd``.
  32
  33   .. code-block:: c++
  34
  35     void f () __attribute__ ((break_handler));
  36
  37 .. index:: interrupt_handler function attribute, MicroBlaze, fast_interrupt function attribute, MicroBlaze
  38
  39 .. microblaze-fn-attr:: interrupt_handler, fast_interrupt
  40
  41   These attributes indicate that the specified function is an interrupt
  42   handler.  Use the :microblaze-fn-attr:`fast_interrupt` attribute to indicate handlers
  43   used in low-latency interrupt mode, and :microblaze-fn-attr:`interrupt_handler` for
  44   interrupts that do not use low-latency handlers.  In both cases, GCC
  45   emits appropriate prologue code and generates a return from the handler
  46   using ``rtid`` instead of ``rtsd``.