From 780137d585344bf9de906a285a50498104c0c66e Mon Sep 17 00:00:00 2001 From: Thiago Macieira Date: Tue, 13 Aug 2019 21:59:26 -0700 Subject: QRandom: add support for RDSEED The Intel whitepaer[1] recommends using the RDSEED over RDRAND whenever present. libstdc++ from GCC 10 will also use it in std::random_device. [ChangeLog][QtCore][QRandomGenerator] The system() random generator will now use the RDSEED instruction on x86 processors whenever available as the first source of random data. It will fall back to RDRAND and then to the system functions, in that order. [1] https://software.intel.com/en-us/articles/intel-digital-random-number-generator-drng-software-implementation-guide Change-Id: I907a43cd9a714da288a2fffd15bab176e54e1975 Reviewed-by: Edward Welbourne --- config.tests/x86_simd/main.cpp | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'config.tests/x86_simd') diff --git a/config.tests/x86_simd/main.cpp b/config.tests/x86_simd/main.cpp index 4fac13973a..0e7ebed8d9 100644 --- a/config.tests/x86_simd/main.cpp +++ b/config.tests/x86_simd/main.cpp @@ -132,6 +132,23 @@ attribute_target("rdrnd") int test_rdrnd() } #endif +#if T(RDSEED) +attribute_target("rdseed") int test_rdseed() +{ + unsigned short us; + unsigned int ui; + if (_rdseed16_step(&us)) + return 1; + if (_rdseed32_step(&ui)) + return 1; +# if defined(__x86_64) || defined(__x86_64__) || defined(__amd64) || defined(_M_X64) + unsigned long long ull; + if (_rdseed64_step(&ull)) + return 1; +# endif +} +#endif + #if T(SHANI) attribute_target("sha") void test_shani() { -- cgit v1.2.3