scripts init

scripts/gen_atan_lut.py

@@ -0,0 +1,50 @@
+#!/usr/bin/env python
+
+"""
+Generate atan Look Up Table (LUT)
+
+Key = math.tan(phase)*SIZE -- phase \in [0, math.pi/4)
+Value = int(math.atan(phase)*SIZE*2)
+
+SIZE is LUT size. The value is scaled up by SIZE*2 so that adjacent LUT values
+can be distinguished.
+"""
+
+SIZE = 2**8
+SCALE = 512
+
+import argparse
+import math
+import os
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--out')
+    args = parser.parse_args()
+
+    if args.out is None:
+        args.out = os.path.join(os.getcwd(), 'atan_lut.mif')
+    coe_out = '%s.coe' % (os.path.splitext(args.out)[0])
+
+    data = []
+    with open(args.out, 'w') as f:
+        for i in range(SIZE):
+            key = float(i)/SIZE
+            val = int(round(math.atan(key)*SCALE))
+            data.append(val)
+            print '%f -> %d' % (key, val)
+            f.write('{0:09b}\n'.format(val))
+    print "LUT SIZE %d, SCALE %d" % (SIZE, SCALE)
+    print "MIL file saved as %s" % (args.out)
+
+    with open(coe_out, 'w') as f:
+        f.write('memory_initialization_radix=2;\n')
+        f.write('memory_initialization_vector=\n')
+        f.write(',\n'.join(['{0:09b}'.format(l) for l in data]))
+        f.write(';')
+    print "COE file saved as %s" % (coe_out)
+
+
+if __name__ == '__main__':
+    main()