diff --git a/src/cpu/386_dynarec.c b/src/cpu/386_dynarec.c
index 9c887db29..61978af3b 100644
--- a/src/cpu/386_dynarec.c
+++ b/src/cpu/386_dynarec.c
@@ -477,7 +477,7 @@ int idivl(int32_t val)
          rem=num%val;
          quo32=(int32_t)(quo&0xFFFFFFFF);
 
-        if (quo!=(int64_t)quo32) 
+	if ((quo > 0x000000007FFFFFFFLL) || (quo < 0xFFFFFFFF80000000LL))
         {
                 divexcp();
                 return 1;
diff --git a/src/cpu/x86_ops_misc.h b/src/cpu/x86_ops_misc.h
index 7448007fb..517f22d72 100644
--- a/src/cpu/x86_ops_misc.h
+++ b/src/cpu/x86_ops_misc.h
@@ -67,7 +67,6 @@ static int opF6_a16(uint32_t fetchdat)
         int tempws, tempws2 = 0;
         uint16_t tempw, src16;
         uint8_t src, dst;
-        int8_t temps;
         
         fetch_ea_16(fetchdat);
         dst = geteab();                 if (cpu_state.abrt) return 1;
@@ -133,8 +132,7 @@ static int opF6_a16(uint32_t fetchdat)
                 case 0x38: /*IDIV AL,b*/
                 tempws = (int)(int16_t)AX;
                 if (dst != 0) tempws2 = tempws / (int)((int8_t)dst);
-                temps = tempws2 & 0xff;
-                if (dst && ((int)temps == tempws2))
+                if (dst && ((tempws2 > 0x0000007F) || (tempws2 < 0xFFFFFF80)))
                 {
                         AH = (tempws % (int)((int8_t)dst)) & 0xff;
                         AL = tempws2 & 0xff;
@@ -164,7 +162,6 @@ static int opF6_a32(uint32_t fetchdat)
         int tempws, tempws2 = 0;
         uint16_t tempw, src16;
         uint8_t src, dst;
-        int8_t temps;
         
         fetch_ea_32(fetchdat);
         dst = geteab();                 if (cpu_state.abrt) return 1;
@@ -230,8 +227,7 @@ static int opF6_a32(uint32_t fetchdat)
                 case 0x38: /*IDIV AL,b*/
                 tempws = (int)(int16_t)AX;
                 if (dst != 0) tempws2 = tempws / (int)((int8_t)dst);
-                temps = tempws2 & 0xff;
-                if (dst && ((int)temps == tempws2))
+                if (dst && ((tempws2 > 0x0000007F) || (tempws2 < 0xFFFFFF80)))
                 {
                         AH = (tempws % (int)((int8_t)dst)) & 0xff;
                         AL = tempws2 & 0xff;
@@ -263,7 +259,6 @@ static int opF7_w_a16(uint32_t fetchdat)
 {
         uint32_t templ, templ2;
         int tempws, tempws2 = 0;
-        int16_t temps16;
         uint16_t src, dst;
         
         fetch_ea_16(fetchdat);
@@ -329,8 +324,7 @@ static int opF7_w_a16(uint32_t fetchdat)
                 case 0x38: /*IDIV AX,w*/
                 tempws = (int)((DX << 16)|AX);
                 if (dst) tempws2 = tempws / (int)((int16_t)dst);
-                temps16 = tempws2 & 0xffff;
-                if ((dst != 0) && ((int)temps16 == tempws2))
+                if ((dst != 0) && ((tempws2 > 0x00007FFF) || (tempws2 < 0xFFFF8000)))
                 {
                         DX = tempws % (int)((int16_t)dst);
                         AX = tempws2 & 0xffff;
@@ -355,7 +349,6 @@ static int opF7_w_a32(uint32_t fetchdat)
 {
         uint32_t templ, templ2;
         int tempws, tempws2 = 0;
-        int16_t temps16;
         uint16_t src, dst;
 
         fetch_ea_32(fetchdat);
@@ -421,8 +414,7 @@ static int opF7_w_a32(uint32_t fetchdat)
                 case 0x38: /*IDIV AX,w*/
                 tempws = (int)((DX << 16)|AX);
                 if (dst) tempws2 = tempws / (int)((int16_t)dst);
-                temps16 = tempws2 & 0xffff;
-                if ((dst != 0) && ((int)temps16 == tempws2))
+                if ((dst != 0) && ((tempws2 > 0x00007FFF) || (tempws2 < 0xFFFF8000)))
                 {
                         DX = tempws % (int)((int16_t)dst);
                         AX = tempws2 & 0xffff;
diff --git a/src/mouse_bus.c b/src/mouse_bus.c
index ec72b4187..cbe4ba40a 100644
--- a/src/mouse_bus.c
+++ b/src/mouse_bus.c
@@ -53,7 +53,7 @@
  *		only the Logitech part is considered to
  *		be OK.
  *
- * Version:	@(#)mouse_bus.c	1.0.27	2017/12/09
+ * Version:	@(#)mouse_bus.c	1.0.28	2017/12/14
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *
@@ -584,6 +584,7 @@ bm_close(void *priv)
 		     bm_read, NULL, NULL, bm_write, NULL, NULL, dev);
 
     free(dev);
+    dev = NULL;
 }
 
 
diff --git a/src/mouse_ps2.c b/src/mouse_ps2.c
index 312038883..c5e9af72d 100644
--- a/src/mouse_ps2.c
+++ b/src/mouse_ps2.c
@@ -8,7 +8,7 @@
  *
  *		Implementation of PS/2 series Mouse devices.
  *
- * Version:	@(#)mouse_ps2.c	1.0.3	2017/12/09
+ * Version:	@(#)mouse_ps2.c	1.0.4	2017/12/13
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  */
@@ -261,6 +261,7 @@ ps2_close(void *priv)
     keyboard_at_set_mouse(NULL, NULL);
 
     free(dev);
+    dev = NULL;
 }
 
 
diff --git a/src/mouse_serial.c b/src/mouse_serial.c
index c723d3ae0..5907898ed 100644
--- a/src/mouse_serial.c
+++ b/src/mouse_serial.c
@@ -10,7 +10,7 @@
  *
  * TODO:	Add the Genius Serial Mouse.
  *
- * Version:	@(#)mouse_serial.c	1.0.16	2017/12/09
+ * Version:	@(#)mouse_serial.c	1.0.17	2017/12/13
  *
  * Author:	Fred N. van Kempen, <decwiz@yahoo.com>
  */
@@ -199,12 +199,13 @@ sermouse_close(void *priv)
     mouse_t *dev = (mouse_t *)priv;
 
     /* Detach serial port from the mouse. */
-    if (dev->serial != NULL) {
+    if ((dev != NULL) && (dev->serial != NULL)) {
 	dev->serial->rcr_callback = NULL;
 	dev->serial->rcr_callback_p = NULL;
     }
 
     free(dev);
+    dev = NULL;
 }