diff options
Diffstat (limited to 'src/lib/entropy/rdrand')
| -rw-r--r-- | src/lib/entropy/rdrand/rdrand.cpp | 35 |
1 files changed, 18 insertions, 17 deletions
diff --git a/src/lib/entropy/rdrand/rdrand.cpp b/src/lib/entropy/rdrand/rdrand.cpp index 24fe98cf8..13263bb63 100644 --- a/src/lib/entropy/rdrand/rdrand.cpp +++ b/src/lib/entropy/rdrand/rdrand.cpp @@ -1,12 +1,14 @@ /* * Entropy Source Using Intel's rdrand instruction * (C) 2012,2015 Jack Lloyd +* (C) 2015 Daniel Neus * * Botan is released under the Simplified BSD License (see license.txt) */ #include <botan/internal/rdrand.h> #include <botan/cpuid.h> +#include <botan/build.h> #if !defined(BOTAN_USE_GCC_INLINE_ASM) #include <immintrin.h> @@ -14,32 +16,31 @@ namespace Botan { -/* -* Get the timestamp -*/ -void Intel_Rdrand::poll(Entropy_Accumulator& accum) - { +void Intel_Rdrand::poll(Entropy_Accumulator& accum) { if(!CPUID::has_rdrand()) return; - const size_t RDRAND_POLLS = 32; - - for(size_t i = 0; i != RDRAND_POLLS; ++i) + for(size_t i = 0; i != BOTAN_ENTROPY_INTEL_RNG_POLLS; ++i) { - unsigned int r = 0; + for(size_t i = 0; i != BOTAN_ENTROPY_RDRAND_RETRIES; ++i) + { + uint32_t r = 0; #if defined(BOTAN_USE_GCC_INLINE_ASM) - int cf = 0; + int cf = 0; - // Encoding of rdrand %eax - asm(".byte 0x0F, 0xC7, 0xF0; adcl $0,%1" : - "=a" (r), "=r" (cf) : "0" (r), "1" (cf) : "cc"); + // Encoding of rdrand %eax + asm(".byte 0x0F, 0xC7, 0xF0; adcl $0,%1" : + "=a" (r), "=r" (cf) : "0" (r), "1" (cf) : "cc"); #else - int cf = _rdrand32_step(&r); + int cf = _rdrand32_step(&r); #endif - - if(cf == 1) - accum.add(r, BOTAN_ENTROPY_ESTIMATE_HARDWARE_RNG); + if(1 == cf) + { + accum.add(r, BOTAN_ENTROPY_ESTIMATE_HARDWARE_RNG); + break; + } + } } } |