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				/*
				* Written by Matthias Drochner <drochner@NetBSD.org>.
				* Public domain.
				*/

				#ifndef CONSTTIME_MEMEQUAL_H
				#define CONSTTIME_MEMEQUAL_H
				inline static 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));
				}
				#endif /* CONSTTIME_MEMEQUAL_H */