mirror of
https://github.com/corda/corda.git
synced 2025-01-08 14:03:06 +00:00
9441de4c38
This release is used in conjunction with the linux-sgx-driver Intial release: https://github.com/01org/linux-sgx-driver commit-id: 0e865ce5e6b297a787bcdc12d98bada8174be6d7 Intel-id: 33399 Signed-off-by: Angie Chinchilla <angie.v.chinchilla@intel.com>
30 lines
694 B
C
30 lines
694 B
C
/* $NetBSD: consttime_memequal.c,v 1.6 2015/03/18 20:11:35 riastradh Exp $ */
|
|
|
|
/*
|
|
* Written by Matthias Drochner <drochner@NetBSD.org>.
|
|
* Public domain.
|
|
*/
|
|
|
|
#include <string.h>
|
|
|
|
int
|
|
consttime_memequal(const void *b1, const void *b2, size_t len)
|
|
{
|
|
const unsigned char *c1 = b1, *c2 = b2;
|
|
unsigned int res = 0;
|
|
|
|
while (len--)
|
|
res |= *c1++ ^ *c2++;
|
|
|
|
/*
|
|
* Map 0 to 1 and [1, 256) to 0 using only constant-time
|
|
* arithmetic.
|
|
*
|
|
* This is not simply `!res' because although many CPUs support
|
|
* branchless conditional moves and many compilers will take
|
|
* advantage of them, certain compilers generate branches on
|
|
* certain CPUs for `!res'.
|
|
*/
|
|
return (1 & ((res - 1) >> 8));
|
|
}
|