GCC provides many FR-V-specific built-in functions. In general, these functions are intended to be compatible with those described by FR-V Family, Softune C/C++ Compiler Manual (V6), Fujitsu Semiconductor
. The two exceptions are
, the GCC forms of which pass 128-bit values by pointer rather than by value.
Most of the functions are named after specific FR-V instructions. Such functions are said to be “directly mapped” and are summarized here in tabular form.