From 76506bd3d10214aa3f3d12dad60e8da729fc318c Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Mon, 7 Mar 2011 18:13:02 +0100 Subject: [PATCH] Introduce and use rot() in rkiss.h Also fix indentation. No functional change. Signed-off-by: Marco Costalba --- src/rkiss.h | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/src/rkiss.h b/src/rkiss.h index 924b6c65..0863c9cf 100644 --- a/src/rkiss.h +++ b/src/rkiss.h @@ -46,24 +46,28 @@ class RKISS { // Keep variables always together struct S { uint64_t a, b, c, d; } s; - // Return 64 bit unsigned integer in between [0,2^64-1] + uint64_t rot(uint64_t x, uint64_t k) const { + return (x << k) | (x >> (64 - k)); + } + + // Return 64 bit unsigned integer in between [0, 2^64 - 1] uint64_t rand64() { - const uint64_t - e = s.a - ((s.b << 7) | (s.b >> 57)); - s.a = s.b ^ ((s.c << 13) | (s.c >> 51)); - s.b = s.c + ((s.d << 37) | (s.d >> 27)); - s.c = s.d + e; - return s.d = e + s.a; + const uint64_t + e = s.a - rot(s.b, 7); + s.a = s.b ^ rot(s.c, 13); + s.b = s.c + rot(s.d, 37); + s.c = s.d + e; + return s.d = e + s.a; } // Init seed and scramble a few rounds void raninit() { - s.a = 0xf1ea5eed; - s.b = s.c = s.d = 0xd4e12c77; - for (int i = 0; i < 73; i++) - rand64(); + s.a = 0xf1ea5eed; + s.b = s.c = s.d = 0xd4e12c77; + for (int i = 0; i < 73; i++) + rand64(); } public: -- 2.39.2