From 592a85d102a13714722c716d5af811114a46ec15 Mon Sep 17 00:00:00 2001
From: MITSUNARI Shigeo <herumi@nifty.com>
Date: Fri, 7 Jun 2024 13:28:24 +0900
Subject: [PATCH] [doc] add comment of split

---
 misc/internal.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/misc/internal.md b/misc/internal.md
index a7307177..9f7fa891 100644
--- a/misc/internal.md
+++ b/misc/internal.md
@@ -163,3 +163,7 @@ def naf(x, w=3):
     tbl.reverse()
   return tbl
 ```
+
+Consider to apply `w=5` to `(a, b)=split(x)`.
+The max value of `a` is `1.1 L = 0b101...` of 128-bit length.
+`0b101` is less than `(1<<(w-1))-1` and so negativity and CF operation are unnecessary.