| ============== |
| RISC-V Support |
| ============== |
| |
| .. contents:: |
| :local: |
| |
| Intrinsic Detection Macros |
| =========================== |
| |
| Clang provides macros to detect which RISC-V intrinsics are supported by the |
| toolchain. This is only available if intrinsics are ratified, in other word, |
| experimental intrinsics do not have macro defined. |
| Note: This is independent from assembler support. |
| |
| Intrinsic Detection |
| --------------------------- |
| |
| Macros of the form ``__riscv_intrinsic_<extension>`` indicate that the toolchain |
| supports intrinsics for a given extension: |
| |
| .. code-block:: c |
| |
| #if defined(__riscv_intrinsic_zbb) |
| // Toolchain supports Zbb scalar intrinsics like __riscv_orc_b_* |
| // These can be used with target attributes even if -march doesn't include Zbb |
| __attribute__((target("arch=+zbb"))) |
| unsigned long process_with_zbb(unsigned long x) { |
| return __riscv_orc_b_64(x); |
| } |
| #endif |
| |
| Composite extensions are also defined when all their sub-extensions are available, e.g. |
| ``__riscv_intrinsic_zkn`` - zbkb + zbkc + zbkx + zkne + zknd + zknh |
