From 538300eed841e9c750ae7aee6ca358b844e539e1 Mon Sep 17 00:00:00 2001 From: "adam@algroup.co.uk" Date: Tue, 4 May 2010 14:31:54 +0000 Subject: [PATCH] legic code tidy up [Hagen Fritsch] --- common/legic_prng.c | 22 ++++------------------ 1 file changed, 4 insertions(+), 18 deletions(-) diff --git a/common/legic_prng.c b/common/legic_prng.c index 1d28fdb7..54d2466e 100644 --- a/common/legic_prng.c +++ b/common/legic_prng.c @@ -22,27 +22,13 @@ void legic_prng_init(uint8_t init) { } void legic_prng_forward(int count) { - uint8_t tmp; while(count--) { - tmp = lfsr.a & 1; - tmp ^= (lfsr.a & 0x40) >> 6; - - lfsr.a >>= 1; - lfsr.a |= tmp << 6; - - tmp = lfsr.b & 1; - tmp ^= (lfsr.b & 4) >> 2; - tmp = ~tmp; - tmp ^= (lfsr.b & 8) >> 3; - tmp = ~tmp; - tmp ^= (lfsr.b & 0x80) >> 7; - - lfsr.b >>= 1; - lfsr.b |= tmp << 7; + lfsr.a = lfsr.a >> 1 | (lfsr.a ^ lfsr.a >> 6) << 6; + lfsr.b = lfsr.b >> 1 | (lfsr.b ^ lfsr.b >> 2 ^ lfsr.b >> 3 ^ lfsr.b >> 7) << 7; } } uint8_t legic_prng_get_bit() { - uint8_t idx = 7-((lfsr.a & 4) | ((lfsr.a & 8) >> 2) | ((lfsr.a & 0x10) >> 4)); - return ((lfsr.b >> idx) & 1); + uint8_t idx = 7 - ( (lfsr.a & 4) | (lfsr.a >> 2 & 2) | (lfsr.a >> 4 & 1) ); + return lfsr.b >> idx & 1; } -- 2.39.5