From d9affa3caecaa9531d109c7f2b953432ee0ae0a2 Mon Sep 17 00:00:00 2001
From: Nero <41307858+nero@users.noreply.github.com>
Date: Tue, 20 Apr 2021 16:27:10 +0000
Subject: [PATCH] Kernel: Fix segmenting bugs

---
 com/@rdos.asm    |  9 +++++++--
 kernel/far.asm   | 12 ++++++++++++
 rom/uartctrl.asm |  4 ++++
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/com/@rdos.asm b/com/@rdos.asm
index f3fb108..83e817a 100644
--- a/com/@rdos.asm
+++ b/com/@rdos.asm
@@ -23,15 +23,20 @@ init:	call rstseg
 
 	call rstseg
 	mov dx, testdta
+	push ds
+	call norm
 	call setdta
+	pop ds
+
 	mov dx, testfcb
+	call norm
 
 	call open
 
-	int 3
-
 	call read
 
+	mov ax, [cs:testdta]
+	mov cx, [cs:testdta+2]
 	int 3
 
 hlt:	hlt
diff --git a/kernel/far.asm b/kernel/far.asm
index 239cd2b..a799241 100644
--- a/kernel/far.asm
+++ b/kernel/far.asm
@@ -32,3 +32,15 @@ xchgdes	push ds
 	pop ds
 	pop es
 	ret
+
+	; normalize ptr in ds:dx
+norm	mov ax, ds
+	mov cl, 4
+	push dx
+	ror dx, cl
+	and dh, 0xF
+	add ax, dx
+	mov ds, ax
+	pop dx
+	and dx, 0xF
+	ret
diff --git a/rom/uartctrl.asm b/rom/uartctrl.asm
index b5bd775..ae0ced3 100644
--- a/rom/uartctrl.asm
+++ b/rom/uartctrl.asm
@@ -77,6 +77,10 @@ init	push ax
 	mov al, 8
 	out dx, al
 
+	; DS = interrupt table
+	xor ax, ax
+	mov ds, ax
+
 	; hook video services
 	; keep original ptr in intvec 47h for chaining
 	mov ax, int10