#### 6.55.11 picoChip Built-in Functions

GCC provides an interface to selected machine instructions from the picoChip instruction set.

`int __builtin_sbc (int` value`)`
  Sign bit count. Return the number of consecutive bits in value which have the same value as the sign-bit. The result is the number of leading sign bits minus one, giving the number of redundant sign bits in value.
`int __builtin_byteswap (int` value`)`
  Byte swap. Return the result of swapping the upper and lower bytes of value.
`int __builtin_brev (int` value`)`
  Bit reversal. Return the result of reversing the bits in value. Bit 15 is swapped with bit 0, bit 14 is swapped with bit 1, and so on.
`int __builtin_adds (int` x`, int` y`)`
  Saturating addition. Return the result of adding x and y, storing the value 32767 if the result overflows.
`int __builtin_subs (int` x`, int` y`)`
  Saturating subtraction. Return the result of subtracting y from x, storing the value −32768 if the result overflows.
`void __builtin_halt (void)`
  Halt. The processor will stop execution. This built-in is useful for implementing assertions.