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legic code tidy up [Hagen Fritsch]

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adam@algroup.co.uk 2010-05-04 14:31:54 +00:00
parent 346ad5fbbb
commit 538300eed8
1 changed files with 4 additions and 18 deletions
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22
common/legic_prng.c
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@ -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;
}