From: John Tsiombikas <nuclear@member.fsf.org>
Date: Sat, 30 Sep 2023 05:07:28 +0000 (+0300)
Subject: detect vm86 and abort
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=commitdiff_plain;h=b1376a2afb38686f04da0eaccdb18ff867f2d639;p=com32

detect vm86 and abort
---

diff --git a/src/loader.asm b/src/loader.asm
index 4f3d99d..6b4f288 100644
--- a/src/loader.asm
+++ b/src/loader.asm
@@ -18,7 +18,16 @@ _start:
 	xor ax, ax
 	mov sp, ax
 
+	; check for VM86 and abort
+	mov eax, cr0
+	test ax, 1
+	jz .notvm86
+
+	mov si, str_errvm86
+	call printstr
+	jmp exit
 
+.notvm86:
 	call enable_a20
 
 	; calculate GDT linear address
@@ -78,9 +87,10 @@ _start:
 	mov es, ax
 	mov ss, ax
 
-	mov ax, 4c00h
+exit:	mov ax, 4c00h
 	int 21h
 
+str_errvm86 db 'Error: memory manager detected! Stop it and try again (e.g. emm386 off)',10,0
 str_enterpm db 'Entering 32bit protected mode ...',10,0
 
 enable_a20: