From 96bf0e28d6131533c9b520b43ffe743c64f2d060 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Strohh=C3=A4cker?=
 <c2woody@users.sourceforge.net>
Date: Thu, 24 Nov 2005 17:05:22 +0000
Subject: [PATCH] add error handling for DOS_SetMemAllocStrategy

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@2385
---
 include/dos_inc.h      |  4 ++--
 src/dos/dos.cpp        |  8 ++++++--
 src/dos/dos_memory.cpp | 19 +++++++++++--------
 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/include/dos_inc.h b/include/dos_inc.h
index 6cf48b8c..997807dd 100644
--- a/include/dos_inc.h
+++ b/include/dos_inc.h
@@ -16,7 +16,7 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: dos_inc.h,v 1.57 2005-11-07 21:08:11 c2woody Exp $ */
+/* $Id: dos_inc.h,v 1.58 2005-11-24 17:05:19 c2woody Exp $ */
 
 #ifndef DOSBOX_DOS_INC_H
 #define DOSBOX_DOS_INC_H
@@ -156,7 +156,7 @@ bool DOS_ResizeMemory(Bit16u segment,Bit16u * blocks);
 bool DOS_FreeMemory(Bit16u segment);
 void DOS_FreeProcessMemory(Bit16u pspseg);
 Bit16u DOS_GetMemory(Bit16u pages);
-void DOS_SetMemAllocStrategy(Bit16u strat);
+bool DOS_SetMemAllocStrategy(Bit16u strat);
 Bit16u DOS_GetMemAllocStrategy(void);
 void DOS_BuildUMBChain(const char* use_umbs,bool ems_active);
 bool DOS_LinkUMBsToMemChain(Bit16u linkstate);
diff --git a/src/dos/dos.cpp b/src/dos/dos.cpp
index e16898fe..32d8f693 100644
--- a/src/dos/dos.cpp
+++ b/src/dos/dos.cpp
@@ -16,7 +16,7 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: dos.cpp,v 1.89 2005-11-17 13:16:34 qbix79 Exp $ */
+/* $Id: dos.cpp,v 1.90 2005-11-24 17:05:22 c2woody Exp $ */
 
 #include <stdlib.h>
 #include <string.h>
@@ -720,7 +720,11 @@ static Bitu DOS_21Handler(void) {
 			reg_ax=DOS_GetMemAllocStrategy();
 			break;
 		case 1:					/* Set Strategy */
-			DOS_SetMemAllocStrategy(reg_bx);
+			if (DOS_SetMemAllocStrategy(reg_bx)) CALLBACK_SCF(false);
+			else {
+				reg_ax=1;
+				CALLBACK_SCF(true);
+			}
 			break;
 		case 2:					/* Get UMB Link Status */
 			reg_al=dos_infoblock.GetUMBChainState()&1;
diff --git a/src/dos/dos_memory.cpp b/src/dos/dos_memory.cpp
index ebd1ab01..ed30d13b 100644
--- a/src/dos/dos_memory.cpp
+++ b/src/dos/dos_memory.cpp
@@ -68,17 +68,20 @@ void DOS_FreeProcessMemory(Bit16u pspseg) {
 	} else if (umb_start!=0xffff) LOG(LOG_DOSMISC,LOG_ERROR)("Corrupt UMB chain: %x",umb_start);
 
 	DOS_CompressMemory();
-};
+}
 
-Bit16u DOS_GetMemAllocStrategy()
-{
+Bit16u DOS_GetMemAllocStrategy() {
 	return memAllocStrategy;
-};
+}
 
-void DOS_SetMemAllocStrategy(Bit16u strat)
-{
-	memAllocStrategy = strat;
-};
+bool DOS_SetMemAllocStrategy(Bit16u strat) {
+	if ((strat&0x3f)<3) {
+		memAllocStrategy = strat;
+		return true;
+	}
+	/* otherwise an invalid allocation strategy was specified */
+	return false;
+}
 
 bool DOS_AllocateMemory(Bit16u * segment,Bit16u * blocks) {
 	DOS_CompressMemory();