We've gone from 100% success to 64 failures on x87 regressions between r15026 and r15031. Development builds are failing early in boot up with: Exception in the primordial thread "Jikes_RVM_Boot_Thread" while booting: JikesRVM: internal error: recursive use of hardware exception registers (exiting) – Stack – at Lorg/jikesrvm/scheduler/RVMThread; handleUncaughtException(Ljava/lang/Throwable;)V at line 1893 at Lorg/jikesrvm/runtime/RuntimeEntrypoints; handleUncaughtException(Ljava/lang/Throwable;)V at line 978 at Lorg/jikesrvm/runtime/RuntimeEntrypoints; deliverException(Ljava/lang/Throwable;Lorg/jikesrvm/ArchitectureSpecific$Registers;)V at line 973 at Lorg/jikesrvm/runtime/RuntimeEntrypoints; athrow(Ljava/lang/Throwable;)V at line 595 at Lorg/jikesrvm/runtime/DynamicLinker; unimplementedNativeMethod()V at line 60 at Ljava/lang/VMFloat; toString(F)Ljava/lang/String; at line 37 at Ljava/lang/Float; toString(F)Ljava/lang/String; at line 196 at Ljava/lang/StringBuilder; append(F)Ljava/lang/StringBuilder; at line 524 at Ljava/util/HashMap; <init>(IF)V at line 255 at Ljava/util/HashMap; <init>()V at line 209 at Lorg/jikesrvm/classloader/BootstrapClassLoader; boot(Ljava/lang/String;)V at line 77 at Lorg/jikesrvm/VM; finishBooting()V at line 215 at Lorg/jikesrvm/VM; boot()V at line 158