diff -Naur jamvm-1.2.0/src/arm/lock_md.h jamvm-1.2.0-mb/src/arm/lock_md.h
--- jamvm-1.2.0/src/arm/lock_md.h	2004-08-18 20:54:02.000000000 +0100
+++ jamvm-1.2.0-mb/src/arm/lock_md.h	2004-11-15 03:35:27.000000000 +0000
@@ -61,3 +61,6 @@
     : "r" (addr), "r" (new_val)                  \
     : "cc", "memory");                           \
 } while(0)
+
+#define MBARRIER() __asm__ __volatile__ ("" ::: "memory")
+
diff -Naur jamvm-1.2.0/src/i386/lock_md.h jamvm-1.2.0-mb/src/i386/lock_md.h
--- jamvm-1.2.0/src/i386/lock_md.h	2004-08-18 20:54:02.000000000 +0100
+++ jamvm-1.2.0-mb/src/i386/lock_md.h	2004-11-15 02:31:12.000000000 +0000
@@ -34,3 +34,7 @@
 
 #define ATOMIC_READ(addr) *addr
 #define ATOMIC_WRITE(addr, value) *addr = value
+
+#define MBARRIER() __asm__ __volatile__ ("lock; addl $0,0(%%esp)" ::: "memory")
+
+
diff -Naur jamvm-1.2.0/src/interp.c jamvm-1.2.0-mb/src/interp.c
--- jamvm-1.2.0/src/interp.c	2004-09-03 08:57:36.000000000 +0100
+++ jamvm-1.2.0-mb/src/interp.c	2004-11-15 03:35:53.000000000 +0000
@@ -69,15 +69,19 @@
 #define OPCODE_REWRITE_OPERAND1(pc, opcode, operand1)                 \
 {                                                                     \
     pc[0] = OPC_LOCK;                                                 \
+    MBARRIER();                                                       \
     pc[1] = operand1;                                                 \
+    MBARRIER();                                                       \
     pc[0] = opcode;                                                   \
 }
 
 #define OPCODE_REWRITE_OPERAND2(pc, opcode, operand1, operand2)       \
 {                                                                     \
     pc[0] = OPC_LOCK;                                                 \
+    MBARRIER();                                                       \
     pc[1] = operand1;                                                 \
     pc[2] = operand2;                                                 \
+    MBARRIER();                                                       \
     pc[0] = opcode;                                                   \
 }
 
diff -Naur jamvm-1.2.0/src/lock.c jamvm-1.2.0-mb/src/lock.c
--- jamvm-1.2.0/src/lock.c	2004-08-30 11:48:12.000000000 +0100
+++ jamvm-1.2.0-mb/src/lock.c	2004-11-15 02:08:47.000000000 +0000
@@ -29,7 +29,7 @@
 #include "hash.h"
 #include "alloc.h"
 
-#include "lock_md.h"
+#include "lock.h"
 
 /* Trace lock operations and inflation/deflation */
 #ifdef TRACELOCK
diff -Naur jamvm-1.2.0/src/lock.h jamvm-1.2.0-mb/src/lock.h
--- jamvm-1.2.0/src/lock.h	2004-08-18 20:54:02.000000000 +0100
+++ jamvm-1.2.0-mb/src/lock.h	2004-11-15 02:08:34.000000000 +0000
@@ -19,6 +19,7 @@
  */
 
 #include "thread.h"
+#include "lock_md.h"
 
 extern void monitorInit(Monitor *mon);
 extern void monitorLock(Monitor *mon, Thread *self);
diff -Naur jamvm-1.2.0/src/powerpc/lock_md.h jamvm-1.2.0-mb/src/powerpc/lock_md.h
--- jamvm-1.2.0/src/powerpc/lock_md.h	2004-08-18 20:54:02.000000000 +0100
+++ jamvm-1.2.0-mb/src/powerpc/lock_md.h	2004-11-15 03:32:53.000000000 +0000
@@ -38,3 +38,5 @@
 
 #define ATOMIC_READ(addr) *addr
 #define ATOMIC_WRITE(addr, value) *addr = value
+
+#define MBARRIER() __asm__ __volatile__ ("" ::: "memory")
diff -Naur jamvm-1.2.0/src/resolve.c jamvm-1.2.0-mb/src/resolve.c
--- jamvm-1.2.0/src/resolve.c	2004-08-18 20:54:02.000000000 +0100
+++ jamvm-1.2.0-mb/src/resolve.c	2004-11-15 02:42:16.000000000 +0000
@@ -21,6 +21,7 @@
 #include <stdio.h>
 #include <string.h>
 #include "jam.h"
+#include "lock.h"
 
 MethodBlock *findMethod(Class *class, char *methodname, char *type) {
    ClassBlock *cb = CLASS_CB(class);
@@ -118,7 +119,9 @@
                 return NULL;
 
             CP_TYPE(cp, cp_index) = CONSTANT_Locked;
+            MBARRIER();
             CP_INFO(cp, cp_index) = (u4)resolved_class;
+            MBARRIER();
             CP_TYPE(cp, cp_index) = CONSTANT_Resolved;
 
 	    break;
@@ -179,7 +182,9 @@
                 initClass(mb->class);
 
                 CP_TYPE(cp, cp_index) = CONSTANT_Locked;
+                MBARRIER();
                 CP_INFO(cp, cp_index) = (u4)mb;
+                MBARRIER();
                 CP_TYPE(cp, cp_index) = CONSTANT_Resolved;
             } else
                 signalException("java/lang/NoSuchMethodError", methodname);
@@ -237,7 +242,9 @@
 
             if(mb) {
                 CP_TYPE(cp, cp_index) = CONSTANT_Locked;
+                MBARRIER();
                 CP_INFO(cp, cp_index) = (u4)mb;
+                MBARRIER();
                 CP_TYPE(cp, cp_index) = CONSTANT_Resolved;
             } else
                 signalException("java/lang/NoSuchMethodError", methodname);
@@ -284,7 +291,9 @@
                 initClass(fb->class);
 
                 CP_TYPE(cp, cp_index) = CONSTANT_Locked;
+                MBARRIER();
                 CP_INFO(cp, cp_index) = (u4)fb;
+                MBARRIER();
                 CP_TYPE(cp, cp_index) = CONSTANT_Resolved;
             } else
                 signalException("java/lang/NoSuchFieldError", fieldname);
@@ -314,7 +323,9 @@
 
             if(string) {
                 CP_TYPE(cp, cp_index) = CONSTANT_Locked;
+                MBARRIER();
                 CP_INFO(cp, cp_index) = (u4)findInternedString(string);
+                MBARRIER();
                 CP_TYPE(cp, cp_index) = CONSTANT_Resolved;
             }