From 733c26d04a4aa2c62a14f0ff066a70267b53f0b6 Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Mon, 19 Feb 2024 19:09:35 +0100
Subject: [PATCH] Return no mask when the TSS type is 286, closes #4177.

---
 src/cpu/386_common.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/cpu/386_common.c b/src/cpu/386_common.c
index beb6869e9..847408ba8 100644
--- a/src/cpu/386_common.c
+++ b/src/cpu/386_common.c
@@ -1605,6 +1605,9 @@ checkio(uint32_t port, int mask)
 {
     uint32_t t;
 
+    if (!(tr.access & 0x08))
+        return 0;
+
     cpl_override = 1;
     t            = readmemw(tr.base, 0x66);