From fc51e5023ec99fee405ae61ee4ab2c8c9bc66f24 Mon Sep 17 00:00:00 2001
From: withsky <withsky2002@gmail.com>
Date: Wed, 17 Jul 2024 12:06:34 +0000
Subject: [PATCH] math/big: fix comment typo in natdiv.go
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Comment in line 395:
[x₀ < S, so S - x₀ < 0; drop it]
Should be:
[x₀ < S, so S - x₀ > 0; drop it]

The proof is based on S - x₀ > 0, thus it's a typo of comment.

Fixes #68466

Change-Id: I68bb7cb909ba2bfe02a8873f74b57edc6679b72a
GitHub-Last-Rev: 40a2fc80cf22e97e0f535454a9b87b31b2e51421
GitHub-Pull-Request: golang/go#68487
Reviewed-on: https://go-review.googlesource.com/c/go/+/598855
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: Keith Randall <khr@golang.org>
---
 src/math/big/natdiv.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/math/big/natdiv.go b/src/math/big/natdiv.go
index 2172eeca40a..b55f9990cd5 100644
--- a/src/math/big/natdiv.go
+++ b/src/math/big/natdiv.go
@@ -392,7 +392,7 @@ Proof that q ≤ q̂:
 	      ≥ (1/y)·((x₁ - y₁ + 1)·S - x)    [above: q̂·y₁ ≥ x₁ - y₁ + 1]
 	      = (1/y)·(x₁·S - y₁·S + S - x)    [distribute S]
 	      = (1/y)·(S - x₀ - y₁·S)          [-x = -x₁·S - x₀]
-	      > -y₁·S / y                      [x₀ < S, so S - x₀ < 0; drop it]
+	      > -y₁·S / y                      [x₀ < S, so S - x₀ > 0; drop it]
 	      ≥ -1                             [y₁·S ≤ y]
 
 	So q̂ - q > -1.