| //! RDRAND and RDSEED instructions for returning random numbers from an Intel |
| //! on-chip hardware random number generator which has been seeded by an |
| //! on-chip entropy source. |
| |
| #![allow(clippy::module_name_repetitions)] |
| |
| #[allow(improper_ctypes)] |
| extern "unadjusted" { |
| #[link_name = "llvm.x86.rdrand.64"] |
| fn x86_rdrand64_step() -> (u64, i32); |
| #[link_name = "llvm.x86.rdseed.64"] |
| fn x86_rdseed64_step() -> (u64, i32); |
| } |
| |
| #[cfg(test)] |
| use stdarch_test::assert_instr; |
| |
| /// Read a hardware generated 64-bit random value and store the result in val. |
| /// Returns 1 if a random value was generated, and 0 otherwise. |
| /// |
| /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_rdrand64_step) |
| #[inline] |
| #[target_feature(enable = "rdrand")] |
| #[cfg_attr(test, assert_instr(rdrand))] |
| #[stable(feature = "simd_x86", since = "1.27.0")] |
| pub unsafe fn _rdrand64_step(val: &mut u64) -> i32 { |
| let (v, flag) = x86_rdrand64_step(); |
| *val = v; |
| flag |
| } |
| |
| /// Read a 64-bit NIST SP800-90B and SP800-90C compliant random value and store |
| /// in val. Return 1 if a random value was generated, and 0 otherwise. |
| /// |
| /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_rdseed64_step) |
| #[inline] |
| #[target_feature(enable = "rdseed")] |
| #[cfg_attr(test, assert_instr(rdseed))] |
| #[stable(feature = "simd_x86", since = "1.27.0")] |
| pub unsafe fn _rdseed64_step(val: &mut u64) -> i32 { |
| let (v, flag) = x86_rdseed64_step(); |
| *val = v; |
| flag |
| } |