>>>>> "PG" == Peter Gutmann <pgut...@cs.auckland.ac.nz> writes:
PG> Does this mean it's unavailable in 32-bit mode? Unlikely; see below. PG> What does the notation "0F C7 /6" indicate in terms of encoding? It PG> looks like RdRand r16 and r32 have the same encoding, or do you PG> encode (for example) r16 vs. r32 in whatever the "/6" signifies? PG> How would you encode, for example, 'RdRand eax'? AIUI, when the 32-bit and 16-bit versions have the same opcode, that generally means that when the cpu is in 16-bit mode (such as when running venerable DOS or the BIOS) that opcode works on 16-bit registers and when the processor is in 32-bit or 64-bit mode that same opcode works on 32-bit registers. >From p 8-15 of 319433-011.pdf, I presume that the assembly would look like; RDRAND eax ; randomize 32-bit register eax RDRAND rdx ; randomize 64-bit register rax and, in 16-bit code: RDRAND al ; randomize 16-bit register al -JimC -- James Cloos <cl...@jhcloos.com> OpenPGP: 1024D/ED7DAEA6 _______________________________________________ cryptography mailing list cryptography@randombit.net http://lists.randombit.net/mailman/listinfo/cryptography