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SigGen duration bugfix
This commit is contained in:
furrtek 2017-07-22 19:30:20 +01:00
parent 3005403b5e
commit b57b41753f
12 changed files with 18177 additions and 70 deletions
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82
firmware/application/de_bruijn.cpp
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@ -22,50 +22,37 @@
#include "de_bruijn.hpp"
/*
How this works:
B(2,4): 2 states, 4 bits
Primitive poly with n=4: 1001
0001
xor 1001 = 0 ^ 1 = 1
00011
xor 1001 = 0 ^ 1 = 1
000111
xor 1001 = 0 ^ 1 = 1
0001111
xor 1001 = 1 ^ 1 = 0
00011110
xor 1001 = 1 ^ 0 = 1
000111101
xor 1001 = 1 ^ 1 = 0
0001111010
xor 1001 = 0 ^ 1 = 1
00011110101
xor 1001 = 0 ^ 1 = 1
000111101011
xor 1001 = 1 ^ 1 = 0
0001111010110
xor 1001 = 0 ^ 0 = 0
00011110101100
xor 1001 = 1 ^ 0 = 1
000111101011001
xor 1001 = 1 ^ 1 = 0
0001111010110010
xor 1001 = 0 ^ 0 = 0
*/
/* How this works:
* B(2,4) means:
* Alphabet size = 2 (binary)
* Code length = 4
* The length of the bitstream is (2 ^ 4) - 1 = 15
* The primitive polynomials come from the de_bruijn_polys[] array (one for each code length)
* The shift register is init with 1 and shifted left each step
* The polynomial is kept on the right, and ANDed with the corresponding shift register bits
* The resulting bits are XORed together to produce the new bit pushed in the shift register
*
* 0001 (init)
* AND 1001 (polynomial)
* 0001 XOR'd -> 1
*
* 00011 (shift left)
* AND 1001
* 0001 XOR'd -> 1
*
* 000111 (shift left)
* AND 1001
* 0001 XOR'd -> 1
*
* 0001111 (shift left)
* AND 1001
* 1001 XOR'd -> 0
*
* 00011110 (shift left)
* AND 1001
* 1000 XOR'd -> 1
* ...
*/
void de_bruijn::init(const uint32_t n) {
if ((n < 3) || (n > 16))
@ -73,16 +60,15 @@ void de_bruijn::init(const uint32_t n) {
else
length = n;
// k is 2 (binary sequence)
poly = de_bruijn_polys[length - 3];
shift_register = 1;
}
uint32_t de_bruijn::compute(const uint32_t step) {
uint32_t c, bits, masked;
uint32_t de_bruijn::compute(const uint32_t steps) {
uint32_t step, bits, masked;
uint8_t new_bit;
for (c = 0; c < step; c++) {
for (step = 0; step < steps; step++) {
masked = shift_register & poly;
new_bit = 0;
for (bits = 0; bits < length; bits++) {