gcc/doc/gcc/extensions-to-the-c-language-family/declaring-attributes-of-functions/blackfin-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.
   5
   6 .. _blackfin-function-attributes:
   7
   8 Blackfin Function Attributes
   9 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  10
  11 These function attributes are supported by the Blackfin back end:
  12
  13 .. index:: exception_handler function attribute, exception handler functions, Blackfin
  14
  15 .. blackfin-fn-attr:: exception_handler
  16
  17   Use this attribute on the Blackfin to indicate that the specified function
  18   is an exception handler.  The compiler generates function entry and
  19   exit sequences suitable for use in an exception handler when this
  20   attribute is present.
  21
  22 .. index:: interrupt_handler function attribute, Blackfin
  23
  24 .. blackfin-fn-attr:: interrupt_handler
  25
  26   Use this attribute to
  27   indicate that the specified function is an interrupt handler.  The compiler
  28   generates function entry and exit sequences suitable for use in an
  29   interrupt handler when this attribute is present.
  30
  31 .. index:: kspisusp function attribute, Blackfin, User stack pointer in interrupts on the Blackfin
  32
  33 .. blackfin-fn-attr:: kspisusp
  34
  35   When used together with :blackfin-fn-attr:`interrupt_handler`, :blackfin-fn-attr:`exception_handler`
  36   or :blackfin-fn-attr:`nmi_handler`, code is generated to load the stack pointer
  37   from the USP register in the function prologue.
  38
  39 .. index:: l1_text function attribute, Blackfin
  40
  41 .. blackfin-fn-attr:: l1_text
  42
  43   This attribute specifies a function to be placed into L1 Instruction
  44   SRAM. The function is put into a specific section named ``.l1.text``.
  45   With :option:`-mfdpic`, function calls with a such function as the callee
  46   or caller uses inlined PLT.
  47
  48 .. index:: l2 function attribute, Blackfin
  49
  50 .. blackfin-fn-attr:: l2
  51
  52   This attribute specifies a function to be placed into L2
  53   SRAM. The function is put into a specific section named
  54   ``.l2.text``. With :option:`-mfdpic`, callers of such functions use
  55   an inlined PLT.
  56
  57 .. index:: indirect calls, Blackfin, longcall function attribute, Blackfin, shortcall function attribute, Blackfin
  58
  59 .. blackfin-fn-attr:: longcall, shortcall
  60
  61   The :blackfin-fn-attr:`longcall` attribute
  62   indicates that the function might be far away from the call site and
  63   require a different (more expensive) calling sequence.  The
  64   ``shortcall`` attribute indicates that the function is always close
  65   enough for the shorter calling sequence to be used.  These attributes
  66   override the :option:`-mlongcall` switch.
  67
  68 .. index:: nesting function attribute, Blackfin, Allow nesting in an interrupt handler on the Blackfin processor
  69
  70 .. blackfin-fn-attr:: nesting
  71
  72   Use this attribute together with :blackfin-fn-attr:`interrupt_handler`,
  73   :blackfin-fn-attr:`exception_handler` or :blackfin-fn-attr:`nmi_handler` to indicate that the function
  74   entry code should enable nested interrupts or exceptions.
  75
  76 .. index:: nmi_handler function attribute, Blackfin, NMI handler functions on the Blackfin processor
  77
  78 .. blackfin-fn-attr:: nmi_handler
  79
  80   Use this attribute on the Blackfin to indicate that the specified function
  81   is an NMI handler.  The compiler generates function entry and
  82   exit sequences suitable for use in an NMI handler when this
  83   attribute is present.
  84
  85 .. index:: saveall function attribute, Blackfin, save all registers on the Blackfin
  86
  87 .. blackfin-fn-attr:: saveall
  88
  89   Use this attribute to indicate that
  90   all registers except the stack pointer should be saved in the prologue
  91   regardless of whether they are used or not.