utils: Add tool for generating float24 printtable

utils/float24printtable.py

@@ -0,0 +1,51 @@
+from math import ceil, log2
+import sys
+
+from float24 import bin_to_int
+
+
+digits = 2
+relative_precision = 0.05
+label = 'float24printtable'
+
+
+def print_table():
+    needed_precision = -ceil(log2(relative_precision**digits))
+
+    combinations = int(2**needed_precision)
+    tablesize = digits * 2**needed_precision
+    print('; {} most significant bits required.'.format(needed_precision))
+    print('; This table requires {} bytes.'.format(tablesize))
+
+    print('{}:'.format(label))
+
+    digit_list = []
+    for x in range(2**needed_precision):
+        xbin = bin(x)[2:]
+        # Pad with zeros if necessary.
+        xbin = '0' * (needed_precision - len(xbin)) + xbin
+        db = ('{:.' + str(digits) + 'f}').format(
+            round(bin_to_int('0.' + xbin), digits))[2:]
+
+        digit_list.append(db)
+
+    # Convert trailing zero values to '9999...', as we accidentally round over
+    # which would result into an absolute error of 1!
+    first_nines = next(i
+                       for i, elem in
+                       enumerate(reversed(digit_list)) if elem != '0' * digits)
+
+    if first_nines != 0:
+        digit_list = digit_list[:-first_nines] + ['9' * digits] * first_nines
+
+    # Assemble lines
+    for db in digit_list:
+        print(' ' * 4 + '.db "{}"'.format(db))
+
+
+def main():
+    print_table()
+
+
+if __name__ == '__main__':
+    sys.exit(main())