diff options
Diffstat (limited to 'src/crypto/rand/asm/rdrand-x86_64.pl')
| -rw-r--r-- | src/crypto/rand/asm/rdrand-x86_64.pl | 52 |
1 files changed, 51 insertions, 1 deletions
diff --git a/src/crypto/rand/asm/rdrand-x86_64.pl b/src/crypto/rand/asm/rdrand-x86_64.pl index a917611..c32a55c 100644 --- a/src/crypto/rand/asm/rdrand-x86_64.pl +++ b/src/crypto/rand/asm/rdrand-x86_64.pl @@ -1,5 +1,19 @@ #!/usr/bin/env perl +# Copyright (c) 2015, Google Inc. +# +# Permission to use, copy, modify, and/or distribute this software for any +# purpose with or without fee is hereby granted, provided that the above +# copyright notice and this permission notice appear in all copies. +# +# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY +# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION +# OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN +# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ + $flavour = shift; $output = shift; if ($flavour =~ /\./) { $output = $flavour; undef $flavour; } @@ -14,11 +28,47 @@ open OUT,"| \"$^X\" $xlate $flavour $output"; print<<___; .text +# CRYPTO_rdrand writes eight bytes of random data from the hardware RNG to +# |out|. It returns one on success or zero on hardware failure. +# int CRYPTO_rdrand(uint8_t out[8]); .globl CRYPTO_rdrand .type CRYPTO_rdrand,\@function,1 .align 16 CRYPTO_rdrand: - .byte 0x48, 0x0f, 0xc7, 0xf0 + xorq %rax, %rax + # This is rdrand %rcx. It sets rcx to a random value and sets the carry + # flag on success. + .byte 0x48, 0x0f, 0xc7, 0xf1 + # An add-with-carry of zero effectively sets %rax to the carry flag. + adcq %rax, %rax + movq %rcx, 0(%rdi) + retq + +# CRYPTO_rdrand_multiple8_buf fills |len| bytes at |buf| with random data from +# the hardware RNG. The |len| argument must be a multiple of eight. It returns +# one on success and zero on hardware failure. +# int CRYPTO_rdrand_multiple8_buf(uint8_t *buf, size_t len); +.globl CRYPTO_rdrand_multiple8_buf +.type CRYPTO_rdrand_multiple8_buf,\@function,2 +.align 16 +CRYPTO_rdrand_multiple8_buf: + test %rsi, %rsi + jz .Lout + movq \$8, %rdx +.Lloop: + # This is rdrand %rcx. It sets rcx to a random value and sets the carry + # flag on success. + .byte 0x48, 0x0f, 0xc7, 0xf1 + jnc .Lerr + movq %rcx, 0(%rdi) + addq %rdx, %rdi + subq %rdx, %rsi + jnz .Lloop +.Lout: + movq \$1, %rax + retq +.Lerr: + xorq %rax, %rax retq ___ |