57 lines
1.0 KiB
Go
57 lines
1.0 KiB
Go
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package main
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import (
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"fmt"
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"log/slog"
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)
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func main() {
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// fib_lfsr()
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galois_lfsr()
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}
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/* taps: 16 14 13 11; feedback polynomial: x^16 + x^14 + x^13 + x^11 + 1 */
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func fib_lfsr() {
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startState := uint16(0xACE1)
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lfsr := startState
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var bit uint16
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period := uint64(0)
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for {
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slog.Info("fib_lfsr", "bit", fmt.Sprintf("%01b", lfsr&1), "lfsr", fmt.Sprintf("%016b", lfsr))
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bit = ((lfsr >> 0) ^ (lfsr >> 2) ^ (lfsr >> 3) ^ (lfsr >> 5)) & 1
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lfsr = (lfsr >> 1) | (bit << 15)
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period++
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if period == 15 {
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break
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}
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if lfsr == startState {
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break
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}
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}
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println(period)
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}
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/* taps: 16 14 13 11; feedback polynomial: x^16 + x^14 + x^13 + x^11 + 1 */
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func galois_lfsr() {
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startState := uint16(0xACE1)
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lfsr := startState
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var bit uint16
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period := uint64(0)
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for {
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slog.Info("galois_lfsr", "bit", fmt.Sprintf("%01b", lfsr&1), "lfsr", fmt.Sprintf("%016b", lfsr))
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bit = lfsr & 1
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lfsr >>= 1
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if bit == 1 {
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lfsr ^= 0xB400
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}
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period++
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// if period == 15 {
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// break
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// }
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if lfsr == startState {
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break
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}
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}
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println(period)
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}
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