1 files changed, 33 insertions, 0 deletions
diff --git a/src/tools/cordic.py b/src/tools/cordic.py
new file mode 100644
index 000000000..6742c90df
--- /dev/null
+++ b/src/tools/cordic.py
@@ -0,0 +1,33 @@
+# compute arctangent table for CORDIC computations in fttrigon.c
+import sys, math
+
+#units  = 64*65536.0   # don't change !!
+units  = 180 * 2**16
+scale  = units/math.pi
+shrink = 1.0
+comma  = ""
+
+print ""
+print "table of arctan( 1/2^n ) for PI = " + repr(units/65536.0) + " units"
+
+for n in range(1,32):
+
+    x = 0.5**n                      # tangent value
+
+    angle  = math.atan(x)           # arctangent
+    angle2 = round(angle*scale)     # arctangent in FT_Angle units
+
+    if angle2 <= 0:
+        break
+
+    sys.stdout.write( comma + repr( int(angle2) ) )
+    comma = ", "
+
+    shrink /= math.sqrt( 1 + x*x )
+
+print
+print "shrink factor    = " + repr( shrink )
+print "shrink factor 2  = " + repr( int( shrink * (2**32) ) )
+print "expansion factor = " + repr( 1/shrink )
+print ""
+