2 * Copyright (c) 2011 Alex Hornung <alex@alexhornung.com>.
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30 #include <machine/asmacros.h>
34 /* int padlock_rng(uint8_t *out, int limit) */
43 * edx: (input) quality factor of rng entropy
44 * edi: (input) buffer for random data
45 autoincremented at end of instruction
46 * eax: (output) rng status word
48 .byte 0x0f, 0xa7, 0xc0 /* xstore-rng */
52 * The lower 5 bits of %eax contain the number of random
54 * If no bytes were stored, there is no more entropy
55 * available, so we finish up.
61 * Increment the count of stored random bytes. The buffer pointer
62 * in edi is auto-incremented by the xstore-rng instruction.
67 * If we haven't already read enough random bytes,
73 /* return the number of stored random bytes. */