1 files changed, 70 insertions, 0 deletions
diff --git a/fw/tools/gold_code_header_gen.py b/fw/tools/gold_code_header_gen.py
new file mode 100644
index 0000000..fa98fce
--- /dev/null
+++ b/fw/tools/gold_code_header_gen.py
@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+
+import sys
+import math
+import textwrap
+import contextlib
+
+import numpy as np
+import scipy.signal as sig
+
+# From https://github.com/mubeta06/python/blob/master/signal_processing/sp/gold.py
+preferred_pairs = {5:[[2],[1,2,3]], 6:[[5],[1,4,5]], 7:[[4],[4,5,6]],
+                        8:[[1,2,3,6,7],[1,2,7]], 9:[[5],[3,5,6]], 
+                        10:[[2,5,9],[3,4,6,8,9]], 11:[[9],[3,6,9]]}
+
+def gen_gold(seq1, seq2):
+    gold = [seq1, seq2]
+    for shift in range(len(seq1)):
+        gold.append(seq1 ^ np.roll(seq2, -shift))
+    return gold
+
+def gold(n):
+    n = int(n)
+    if not n in preferred_pairs:
+        raise KeyError('preferred pairs for %s bits unknown' % str(n))
+    t0, t1 = preferred_pairs[n]
+    (seq0, _st0), (seq1, _st1) = sig.max_len_seq(n, taps=t0), sig.max_len_seq(n, taps=t1)
+    return gen_gold(seq0, seq1)
+
+@contextlib.contextmanager
+def print_include_guards(macro_name):
+    print(f'#ifndef {macro_name}')
+    print(f'#define {macro_name}')
+    yield
+    print(f'#endif /* {macro_name} */')
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser(add_help=False)
+    parser.add_argument('n', type=int, choices=preferred_pairs, help='bit width of shift register. Generate 2**n + 1 sequences of length 2**n - 1.')
+    parser.add_argument('-v', '--variable', default='gold_code_table', help='Name for weak alias of generated table')
+    parser.add_argument('-h', '--header', action='store_true', help='Generate header file')
+    parser.add_argument('-c', '--source', action='store_true', help='Generate table source file')
+    args = parser.parse_args()
+
+    if not args.header != args.source:
+        print('Exactly one of --header and --source must be given.', file=sys.stderr)
+        sys.exit(1)
+
+    nbytes = math.ceil((2**args.n-1)/8)
+
+    if args.source:
+        print('/* THIS IS A GENERATED FILE. DO NOT EDIT! */')
+        print('#include <unistd.h>')
+        print('#include <stdint.h>')
+        print()
+        print(f'/* {args.n} bit gold sequences: {2**args.n+1} sequences of length {2**args.n-1} bit.')
+        print(f' *')
+        print(f' * Each code is packed left-aligned into {nbytes} bytes in big-endian byte order.')
+        print(f' */')
+        print(f'const uint8_t {args.variable}[{2**args.n+1}][{nbytes}] = {{')
+        for i, code in enumerate(gold(args.n)):
+            par = '{' + ' '.join(f'0x{d:02x},' for d in np.packbits(code)) + f'}}, /* {i: 3d} "{"".join(str(x) for x in code)}" */'
+            print(textwrap.fill(par, initial_indent=' '*4, subsequent_indent=' '*4, width=120))
+        print('};')
+        print()
+    else:
+        print('/* THIS IS A GENERATED FILE. DO NOT EDIT! */')
+        with print_include_guards(f'__GOLD_CODE_GENERATED_HEADER_{args.n}__'):
+            print(f'extern const uint8_t {args.variable}[{2**args.n+1}][{nbytes}];')