From 410b9f72d21afa1687aba2fa35a7d7bfd22ecb67 Mon Sep 17 00:00:00 2001
From: Sjoerd van der Berg <harekiet@users.sourceforge.net>
Date: Sat, 28 Feb 2004 09:21:02 +0000
Subject: [PATCH] Added some exceptions for illegal opcodes. Double 0x67
 prefixes should work now. Thnx c2woody

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@1688
---
 src/cpu/core_normal.cpp           | 12 +++++++++---
 src/cpu/core_normal/prefix_66.h   |  1 +
 src/cpu/core_normal/prefix_none.h |  1 +
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/cpu/core_normal.cpp b/src/cpu/core_normal.cpp
index ca04fbfe..e4128d9c 100644
--- a/src/cpu/core_normal.cpp
+++ b/src/cpu/core_normal.cpp
@@ -94,8 +94,8 @@ extern Bitu cycle_count;
 	core.seg_prefix_base=SegBase(_SEG);		\
 	goto restart_prefix;
 
-#define DO_PREFIX_ADDR()					\
-	core.prefixes^=PREFIX_ADDR;				\
+#define DO_PREFIX_ADDR()									\
+	core.prefixes|=(core.prefix_default ^ PREFIX_ADDR) & PREFIX_ADDR;		\
 	goto restart_prefix;
 
 #define DO_PREFIX_REP(_ZERO)				\
@@ -194,9 +194,15 @@ restart_opcode:
 #endif
 		}
 	}
-	decode_end:
+decode_end:
 	LEAVECORE;
 	return CBRET_NONE;
+
+illegal_opcode:
+	LEAVECORE;
+	reg_eip-=core.ip_lookup-core.op_start;
+	CPU_Exception(6,0);
+	goto decode_start;
 }
 
 Bits CPU_Core_Normal_Trap_Run(void) {
diff --git a/src/cpu/core_normal/prefix_66.h b/src/cpu/core_normal/prefix_66.h
index df16c9a3..3e10ce47 100644
--- a/src/cpu/core_normal/prefix_66.h
+++ b/src/cpu/core_normal/prefix_66.h
@@ -167,6 +167,7 @@
 		break;
 	CASE_D(0x63)												/* ARPL Ed,Rd */
 		{
+			if (((cpu.pmode) && (reg_flags & FLAG_VM)) || (!cpu.pmode)) goto illegal_opcode;
 			FillFlags();
 			GetRMrw;
 			if (rm >= 0xc0 ) {
diff --git a/src/cpu/core_normal/prefix_none.h b/src/cpu/core_normal/prefix_none.h
index 6d79d972..f5354374 100644
--- a/src/cpu/core_normal/prefix_none.h
+++ b/src/cpu/core_normal/prefix_none.h
@@ -237,6 +237,7 @@
 		break;
 	CASE_W(0x63)												/* ARPL Ew,Rw */
 		{
+			if (((cpu.pmode) && (reg_flags & FLAG_VM)) || (!cpu.pmode)) goto illegal_opcode;
 			FillFlags();
 			GetRMrw;
 			if (rm >= 0xc0 ) {