src/stdsimd/crates/core_arch/src/x86/rdrand.rs

   1 //! RDRAND and RDSEED instructions for returning random numbers from an Intel
   2 //! on-chip hardware random number generator which has been seeded by an
   3 //! on-chip entropy source.
   4 #![allow(clippy::module_name_repetitions)]
   5
   6 #[allow(improper_ctypes)]
   7 extern "unadjusted" {
   8     #[link_name = "llvm.x86.rdrand.16"]
   9     fn x86_rdrand16_step() -> (u16, i32);
  10     #[link_name = "llvm.x86.rdrand.32"]
  11     fn x86_rdrand32_step() -> (u32, i32);
  12     #[link_name = "llvm.x86.rdseed.16"]
  13     fn x86_rdseed16_step() -> (u16, i32);
  14     #[link_name = "llvm.x86.rdseed.32"]
  15     fn x86_rdseed32_step() -> (u32, i32);
  16 }
  17
  18 #[cfg(test)]
  19 use stdsimd_test::assert_instr;
  20
  21 /// Read a hardware generated 16-bit random value and store the result in val.
  22 /// Returns 1 if a random value was generated, and 0 otherwise.
  23 ///
  24 /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_rdrand16_step)
  25 #[inline]
  26 #[target_feature(enable = "rdrand")]
  27 #[cfg_attr(test, assert_instr(rdrand))]
  28 #[stable(feature = "simd_x86", since = "1.27.0")]
  29 pub unsafe fn _rdrand16_step(val: &mut u16) -> i32 {
  30     let (v, flag) = x86_rdrand16_step();
  31     *val = v;
  32     flag
  33 }
  34
  35 /// Read a hardware generated 32-bit random value and store the result in val.
  36 /// Returns 1 if a random value was generated, and 0 otherwise.
  37 ///
  38 /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_rdrand32_step)
  39 #[inline]
  40 #[target_feature(enable = "rdrand")]
  41 #[cfg_attr(test, assert_instr(rdrand))]
  42 #[stable(feature = "simd_x86", since = "1.27.0")]
  43 pub unsafe fn _rdrand32_step(val: &mut u32) -> i32 {
  44     let (v, flag) = x86_rdrand32_step();
  45     *val = v;
  46     flag
  47 }
  48
  49 /// Read a 16-bit NIST SP800-90B and SP800-90C compliant random value and store
  50 /// in val. Return 1 if a random value was generated, and 0 otherwise.
  51 ///
  52 /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_rdseed16_step)
  53 #[inline]
  54 #[target_feature(enable = "rdseed")]
  55 #[cfg_attr(test, assert_instr(rdseed))]
  56 #[stable(feature = "simd_x86", since = "1.27.0")]
  57 pub unsafe fn _rdseed16_step(val: &mut u16) -> i32 {
  58     let (v, flag) = x86_rdseed16_step();
  59     *val = v;
  60     flag
  61 }
  62
  63 /// Read a 32-bit NIST SP800-90B and SP800-90C compliant random value and store
  64 /// in val. Return 1 if a random value was generated, and 0 otherwise.
  65 ///
  66 /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_rdseed32_step)
  67 #[inline]
  68 #[target_feature(enable = "rdseed")]
  69 #[cfg_attr(test, assert_instr(rdseed))]
  70 #[stable(feature = "simd_x86", since = "1.27.0")]
  71 pub unsafe fn _rdseed32_step(val: &mut u32) -> i32 {
  72     let (v, flag) = x86_rdseed32_step();
  73     *val = v;
  74     flag
  75 }