size_t Intel_Rdseed::poll(RandomNumberGenerator& rng) {
if(CPUID::has_rdseed())
{
for(size_t p = 0; p != BOTAN_ENTROPY_INTEL_RNG_POLLS; ++p)
{
for(size_t i = 0; i != BOTAN_ENTROPY_RDSEED_RETRIES; ++i)
{
uint32_t r = 0;
#if defined(BOTAN_USE_GCC_INLINE_ASM)
int cf = 0;
// Encoding of rdseed %eax
asm(".byte 0x0F, 0xC7, 0xF8; adcl $0,%1" :
"=a" (r), "=r" (cf) : "0" (r), "1" (cf) : "cc");
#else
int cf = _rdseed32_step(&r);
#endif
if(1 == cf)
{
rng.add_entropy_T(r);
break;
}
}
}
}
return 0;
}
