From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Fri, 22 Dec 2023 09:05:59 +0000 (+0000)
Subject: bug 1155: clarify python remap bigmul demo function with short vars
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=220ee02f8976f61cab3201ce3bf4b19f6f6ab482;p=openpower-isa.git

bug 1155: clarify python remap bigmul demo function with short vars
---

diff --git a/src/openpower/test/bigint/powmod.py b/src/openpower/test/bigint/powmod.py
index 73d87b35..13c092e8 100644
--- a/src/openpower/test/bigint/powmod.py
+++ b/src/openpower/test/bigint/powmod.py
@@ -102,19 +102,14 @@ def python_mul_algorithm(a, b):
 def python_mul_remap_algorithm(a, b):
     # version 2 of the MUL_256_X_256_TO_512_ASM algorithm using base 100 rather
     # than 2^64, since that's easier to read.
-    # run this file in a debugger to see all the intermediate values.
-    a_sz = len(a)
-    b_sz = len(b)
-    a_idx = []
-    b_idx = []
-    a_plus_b_idx = []
-    a_plus_b_plus_1_idx = []
+    a_sz, b_sz = len(a), = len(b)
+    ai, bi, apbi, apbp1 = [], [], [], [] # REMAP indices
     for ai in range(a_sz):
         for bi in range(b_sz):
-            a_idx.append(ai)
-            b_idx.append(bi)
-            a_plus_b_idx.append(ai + bi)
-            a_plus_b_plus_1_idx.append(ai + bi + 1)
+            ai.append(ai)
+            bi.append(bi)
+            apbi.append(ai + bi)
+            apbp1.append(ai + bi + 1)
 
     y = [0] * (a_sz + b_sz)
     ca = 0
@@ -124,10 +119,8 @@ def python_mul_remap_algorithm(a, b):
         # always be zero when (i % b_sz == 0).
         # That said, hardware will probably want to pattern-match this to
         # remove the unnecessary dependency through ca.
-        y[a_plus_b_idx[i]], t = maddedu(
-            a[a_idx[i]], b[b_idx[i]], y[a_plus_b_idx[i]])
-        y[a_plus_b_plus_1_idx[i]], ca = adde(
-            y[a_plus_b_plus_1_idx[i]], t, ca)
+        y[apbi[i]], t = maddedu(a[ai[i]], b[bi[i]], y[apbi[i]])
+        y[apbp1[i]], ca = adde(y[apbp1[i]], t, ca)
     return y