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   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 .. _nds32-function-attributes:
   7
   8 NDS32 Function Attributes
   9 ^^^^^^^^^^^^^^^^^^^^^^^^^
  10
  11 These function attributes are supported by the NDS32 back end:
  12
  13 .. index:: exception function attribute, exception handler functions, NDS32
  14
  15 .. nds32-fn-attr:: exception
  16
  17   Use this attribute on the NDS32 target to indicate that the specified function
  18   is an exception handler.  The compiler will generate corresponding sections
  19   for use in an exception handler.
  20
  21 .. index:: interrupt function attribute, NDS32
  22
  23 .. nds32-fn-attr:: interrupt
  24
  25   On NDS32 target, this attribute indicates that the specified function
  26   is an interrupt handler.  The compiler generates corresponding sections
  27   for use in an interrupt handler.  You can use the following attributes
  28   to modify the behavior:
  29
  30   ``nested``
  31
  32     .. index:: nested function attribute, NDS32
  33
  34     This interrupt service routine is interruptible.
  35
  36   ``not_nested``
  37
  38     .. index:: not_nested function attribute, NDS32
  39
  40     This interrupt service routine is not interruptible.
  41
  42   ``nested_ready``
  43
  44     .. index:: nested_ready function attribute, NDS32
  45
  46     This interrupt service routine is interruptible after ``PSW.GIE``
  47     (global interrupt enable) is set.  This allows interrupt service routine to
  48     finish some short critical code before enabling interrupts.
  49
  50   ``save_all``
  51
  52     .. index:: save_all function attribute, NDS32
  53
  54     The system will help save all registers into stack before entering
  55     interrupt handler.
  56
  57   ``partial_save``
  58
  59     .. index:: partial_save function attribute, NDS32
  60
  61     The system will help save caller registers into stack before entering
  62     interrupt handler.
  63
  64 .. index:: naked function attribute, NDS32
  65
  66 .. nds32-fn-attr:: naked
  67
  68   This attribute allows the compiler to construct the
  69   requisite function declaration, while allowing the body of the
  70   function to be assembly code. The specified function will not have
  71   prologue/epilogue sequences generated by the compiler. Only basic
  72   ``asm`` statements can safely be included in naked functions
  73   (see :ref:`basic-asm`). While using extended ``asm`` or a mixture of
  74   basic ``asm`` and C code may appear to work, they cannot be
  75   depended upon to work reliably and are not supported.
  76
  77 .. index:: reset function attribute, NDS32, reset handler functions
  78
  79 .. nds32-fn-attr:: reset
  80
  81   Use this attribute on the NDS32 target to indicate that the specified function
  82   is a reset handler.  The compiler will generate corresponding sections
  83   for use in a reset handler.  You can use the following attributes
  84   to provide extra exception handling:
  85
  86   ``nmi``
  87
  88     .. index:: nmi function attribute, NDS32
  89
  90     Provide a user-defined function to handle NMI exception.
  91
  92   ``warm``
  93
  94     .. index:: warm function attribute, NDS32
  95
  96     Provide a user-defined function to handle warm reset exception.