whoops, no ability to add comments in between functions in pseudocode

[openpower-isa.git] / src / openpower / decoder / isa / fastdctlee.py

diff --git a/src/openpower/decoder/isa/fastdctlee.py b/src/openpower/decoder/isa/fastdctlee.py
index 719c4c93d873cae617743cc6e4d55322cbd1ea6b..40444d4c6b477cb136bd4d3c51fdda87d7d21c76 100644 (file)
--- a/src/openpower/decoder/isa/fastdctlee.py
+++ b/src/openpower/decoder/isa/fastdctlee.py
@@ -97,7 +97,7 @@ def halfrev2(vec, pre_rev=True):
     res = []
     for i in range(len(vec)):
         if pre_rev:
-            res.append(i ^ (i>>1))
+            res.append(vec[i ^ (i>>1)])
         else:
             ri = i
             bl = i.bit_length()
@@ -323,6 +323,9 @@ def inverse_transform(vector, root=True, indent=0):
 # totally cool *in-place* DCT algorithm
 def inverse_transform_iter(vec):
 
+    # in-place, but actually have to protect the input list!
+    vec = deepcopy(vec)
+
     # Initialization
     n = len(vec)
     print ()
@@ -337,7 +340,7 @@ def inverse_transform_iter(vec):
     # *indices* are referenced (two levels of indirection at the moment)
     # pre-reverse the data-swap list so that it *ends up* in the order 0123..
     ji = list(range(n))
-    #ji = halfrev2(ji, True)
+    ji = halfrev2(ji, False)
 
     print ("ri", ri)
     print ("ji", ji)
@@ -347,18 +350,21 @@ def inverse_transform_iter(vec):
     # this table could be cached and used multiple times rather than
     # computed every time.
     ctable = []
-    size = n
-    while size >= 2:
+    size = 2
+    while size <= n:
         halfsize = size // 2
         for i in range(n//size):
             for ci in range(halfsize):
                 ctable.append((math.cos((ci + 0.5) * math.pi / size) * 2.0))
-        size //= 2
+        size *= 2
 
     # first divide element 0 by 2
     vec[0] /= 2.0
 
     print("transform2-inv pre-itersum", vec)
+    vec = [vec[ri[i]] for i in range(n)]
+    vec = halfrev2(vec, True)
+    #print("transform2-inv post-itersum-reorder", vec)
 
     # first the outer butterfly (iterative sum thing)
     n = len(vec)
@@ -372,23 +378,15 @@ def inverse_transform_iter(vec):
             jr.reverse()
             print ("itersum    jr", i+halfsize, i+size, jr)
             for jh in jr:
-                x = vec[jh]
-                y = vec[jh+size]
-                vec[jh+size] = x + y
+                x = vec[ji[ri[jh]]]
+                y = vec[ji[ri[jh+size]]]
+                vec[ji[ri[jh+size]]] = x + y
                 print ("    itersum", size, i, jh, jh+size,
-                        x, y, "jh+sz", vec[jh+size])
+                        x, y, "jh+sz", vec[ji[jh+size]])
         size *= 2
 
     print("transform2-inv post-itersum", vec)
 
-    # and pretend we LDed data in half-swapped *and* bit-reversed order as well
-    # TODO: merge these two
-    #vec = halfrev2(vec, False)
-    vec = [vec[ri[i]] for i in range(n)]
-    ri = list(range(n))
-
-    print("transform2-inv post-reorder", vec)
-
     # start the inner butterfly (coefficients)
     size = 2
     k = 0
@@ -403,28 +401,22 @@ def inverse_transform_iter(vec):
             jr = list(range(i+halfsize, i + size))
             jr.reverse()
             print ("  xform jr", j, jr)
-            vec2 = deepcopy(vec)
             for ci, (jl, jh) in enumerate(zip(j, jr)):
-                #t1, t2 = vec[ri[ji[jl]]], vec[ri[ji[jh]]]
-                t1, t2 = vec[jl], vec[jl+halfsize]
-                coeff = (math.cos((ci + 0.5) * math.pi / size) * 2.0)
-                #coeff = ctable[k]
+                t1, t2 = vec[ji[jl]], vec[ji[jl+halfsize]]
+                #coeff = (math.cos((ci + 0.5) * math.pi / size) * 2.0)
+                coeff = ctable[k]
                 k += 1
                 # normally DCT would use jl+halfsize not jh, here.
                 # to be able to work in-place, the idea is to perform a
                 # swap afterwards.
-                #vec[ri[ji[jl]]] = t1 + t2/coeff
-                #vec[ri[ji[jh]]] = t1 - t2/coeff
-                vec2[jl] = t1 + t2/coeff
-                vec2[jh] = t1 - t2/coeff
+                vec[ji[jl]] = t1 + t2/coeff
+                vec[ji[jl+halfsize]] = t1 - t2/coeff
                 print ("coeff", size, i, "ci", ci,
                         "jl", ri[ji[jl]], "jh", ri[ji[jh]],
                        "i/n", (ci+0.5)/size, coeff,
                         "t1,t2", t1, t2,
-                        "+/i", vec2[jl], vec2[jh])
+                        "+/i", vec[ji[jl]], vec[ji[jh]])
                         #"+/i", vec2[ri[ji[jl]]], vec2[ri[ji[jh]]])
-            vec = vec2
-            continue
             # instead of using jl+halfsize, perform a swap here.
             # use half of j/jr because actually jl+halfsize = reverse(j)
             hz2 = halfsize // 2 # can be zero which stops reversing 1-item lists
@@ -438,7 +430,11 @@ def inverse_transform_iter(vec):
 
     print("post-swapped", ri)
     print("ji-swapped", ji)
-    print("transform2 result", vec)
+    ji = list(range(n))
+    ji = halfrev2(ji, True)
+    print("ji-calc   ", ji)
+
+    print("transform2-inv result", vec)
 
     return vec