removed stray debug prints

rtllib/barrel.py

@@ -2,27 +2,26 @@
 sys.path.append("..")
 from pyrtl import *
 
-
 def barrel_shifter(bitwidth, logbitwidth, shiftIn, bitIn, direction, amount):
     '''Create a barrel shifter that operates on data of width bitwidth.
     logbitwidth is the number of bits specifying the shift (e.g. 5 for 32-bit.)
     shiftIn is the input wire; bitIn is the 1-bit wire giving the value to shift in.
     direction should be 1 for left-shift and 0 for right.
-    amount is the number of bits to shift.'''
+    amount is the number of bits to shift.
+
+    bitwidth and logbitwidth are design-time parameters (python ints).
+    The remaining inputs are pyrtl wires.'''
 
+    # Implement with logN stages muxing between shifted and un-shifted values
     val = shiftIn
     appendval = bitIn
-    print len(val)
-    print len(appendval)
     for i in range(logbitwidth):
-        shamt = pow(2, i)
+        shamt = pow(2, i)  # stages shift 1,2,4,8,...
         newval = mux(direction, truecase=val[:-shamt], falsecase=val[shamt:])
-        print len(newval)
         newval = mux(direction, truecase=concat(newval, appendval), 
-                     falsecase=concat(appendval, newval))
+                     falsecase=concat(appendval, newval))  # Build shifted value for this stage
+        # mux shifted vs. unshifted by using i-th bit of shift amount signal
         val = mux(amount[i], truecase=newval, falsecase=val)
         appendval = concat(appendval, appendval)
-        print len(val)
-        print len(appendval)
 
     return val