gcc/doc/gcc/extensions-to-the-c-language-family/target-builtins/picochip-built-in-functions.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 .. _picochip-built-in-functions:
   7
   8 picoChip Built-in Functions
   9 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  10
  11 GCC provides an interface to selected machine instructions from the
  12 picoChip instruction set.
  13
  14 .. function:: int __builtin_sbc (int value)
  15
  16   Sign bit count.  Return the number of consecutive bits in :samp:`{value}`
  17   that have the same value as the sign bit.  The result is the number of
  18   leading sign bits minus one, giving the number of redundant sign bits in
  19   :samp:`{value}`.
  20
  21 .. function:: int __builtin_byteswap (int value)
  22
  23   Byte swap.  Return the result of swapping the upper and lower bytes of
  24   :samp:`{value}`.
  25
  26 .. function:: int __builtin_brev (int value)
  27
  28   Bit reversal.  Return the result of reversing the bits in
  29   :samp:`{value}`.  Bit 15 is swapped with bit 0, bit 14 is swapped with bit 1,
  30   and so on.
  31
  32 .. function:: int __builtin_adds (int x, int y)
  33
  34   Saturating addition.  Return the result of adding :samp:`{x}` and :samp:`{y}`,
  35   storing the value 32767 if the result overflows.
  36
  37 .. function:: int __builtin_subs (int x, int y)
  38
  39   Saturating subtraction.  Return the result of subtracting :samp:`{y}` from
  40   :samp:`{x}`, storing the value -32768 if the result overflows.
  41
  42 .. function:: void __builtin_halt (void)
  43
  44   Halt.  The processor stops execution.  This built-in is useful for
  45   implementing assertions.