| //! Carry-less Multiplication (CLMUL) |
| //! |
| //! The reference is [Intel 64 and IA-32 Architectures Software Developer's |
| //! Manual Volume 2: Instruction Set Reference, A-Z][intel64_ref] (p. 4-241). |
| //! |
| //! [intel64_ref]: http://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-instruction-set-reference-manual-325383.pdf |
| |
| use crate::core_arch::x86::__m128i; |
| |
| #[cfg(test)] |
| use stdarch_test::assert_instr; |
| |
| #[allow(improper_ctypes)] |
| extern "C" { |
| #[link_name = "llvm.x86.pclmulqdq"] |
| fn pclmulqdq(a: __m128i, round_key: __m128i, imm8: u8) -> __m128i; |
| } |
| |
| /// Performs a carry-less multiplication of two 64-bit polynomials over the |
| /// finite field GF(2^k). |
| /// |
| /// The immediate byte is used for determining which halves of `a` and `b` |
| /// should be used. Immediate bits other than 0 and 4 are ignored. |
| /// |
| /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_mm_clmulepi64_si128) |
| #[inline] |
| #[target_feature(enable = "pclmulqdq")] |
| #[cfg_attr(all(test, not(target_os = "linux")), assert_instr(pclmulqdq, IMM8 = 0))] |
| #[cfg_attr(all(test, target_os = "linux"), assert_instr(pclmullqlqdq, IMM8 = 0))] |
| #[cfg_attr(all(test, target_os = "linux"), assert_instr(pclmulhqlqdq, IMM8 = 1))] |
| #[cfg_attr(all(test, target_os = "linux"), assert_instr(pclmullqhqdq, IMM8 = 16))] |
| #[cfg_attr(all(test, target_os = "linux"), assert_instr(pclmulhqhqdq, IMM8 = 17))] |
| #[rustc_legacy_const_generics(2)] |
| #[stable(feature = "simd_x86", since = "1.27.0")] |
| pub unsafe fn _mm_clmulepi64_si128<const IMM8: i32>(a: __m128i, b: __m128i) -> __m128i { |
| static_assert_imm8!(IMM8); |
| pclmulqdq(a, b, IMM8 as u8) |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| // The constants in the tests below are just bit patterns. They should not |
| // be interpreted as integers; signedness does not make sense for them, but |
| // __m128i happens to be defined in terms of signed integers. |
| #![allow(overflowing_literals)] |
| |
| use stdarch_test::simd_test; |
| |
| use crate::core_arch::x86::*; |
| |
| #[simd_test(enable = "pclmulqdq")] |
| unsafe fn test_mm_clmulepi64_si128() { |
| // Constants taken from https://software.intel.com/sites/default/files/managed/72/cc/clmul-wp-rev-2.02-2014-04-20.pdf |
| let a = _mm_set_epi64x(0x7b5b546573745665, 0x63746f725d53475d); |
| let b = _mm_set_epi64x(0x4869285368617929, 0x5b477565726f6e5d); |
| let r00 = _mm_set_epi64x(0x1d4d84c85c3440c0, 0x929633d5d36f0451); |
| let r01 = _mm_set_epi64x(0x1bd17c8d556ab5a1, 0x7fa540ac2a281315); |
| let r10 = _mm_set_epi64x(0x1a2bf6db3a30862f, 0xbabf262df4b7d5c9); |
| let r11 = _mm_set_epi64x(0x1d1e1f2c592e7c45, 0xd66ee03e410fd4ed); |
| |
| assert_eq_m128i(_mm_clmulepi64_si128::<0x00>(a, b), r00); |
| assert_eq_m128i(_mm_clmulepi64_si128::<0x10>(a, b), r01); |
| assert_eq_m128i(_mm_clmulepi64_si128::<0x01>(a, b), r10); |
| assert_eq_m128i(_mm_clmulepi64_si128::<0x11>(a, b), r11); |
| |
| let a0 = _mm_set_epi64x(0x0000000000000000, 0x8000000000000000); |
| let r = _mm_set_epi64x(0x4000000000000000, 0x0000000000000000); |
| assert_eq_m128i(_mm_clmulepi64_si128::<0x00>(a0, a0), r); |
| } |
| } |