摘要:
A system and method for providing exceptional flow control in protected code through watchpoints is described. Code is generated. The generated code includes a sequence of normal operations and is subject to protection against copying during execution of the generated code. Execution points within the generated code are identified. A watchpoint corresponding to each of the execution points is set. An exception handler associated with each watchpoint is defined and includes operations exceptional to the normal operations sequence that are performed upon a triggering of each watchpoint during execution of the generated code.
摘要:
A system and method for providing exceptional flow control in protected code through memory layers. Code is generated. The generated code includes a sequence of normal operations and is subject to protection against copying during execution of the generated code. The generated code is instantiated as a master process into a master layer in a memory space. The master process is cloned by instantiating a copy of the master process as a child layer in the memory space. Execution points within the generated code are identified. A copy of at least a portion of the generated code containing each execution point as an exception layer is instantiated in the memory space. The generated code in the exception layer is patched at each identified execution point with operations exceptional to the normal operations sequence and which are performed upon a triggering of each execution point during execution of the generated code.
摘要:
Techniques for assuring thread rendezvous for a plurality of threads executing in a computing system are disclosed. Techniques can be used to assure thread rendezvous for read-only code in a manner that is more efficient than polling techniques. A Light-weight, Yet Trappable On Demand (LYTOD) instruction can be generated for code that is executed by one or more threads. Typically, a LYTOD instruction is generated at critical points of the code in order to assure safe-point thread rendezvous. The LYTOD is a lightweight instruction that can change its behavior from a lightweight instruction to an instruction that causes a trap when executed. The LYTOD can, for example, be implemented as a read-from-memory instruction that operates to load a register with a content of a valid memory location.
摘要:
Methods and apparatus for eliminating C recursion from interpreter loops are disclosed. According to one aspect of the present invention, a computer-implemented method for substantially eliminating C recursion from the execution of static initializer methods in a virtual machine environment includes rewriting native C code associated with a static initializer as a Java programming language method, and using a transition frame in a Java programming language stack to execute the Java programming language method. The method also includes using a native method to manipulate the Java programming language stack, and using a first opcode in the transition frame. In one embodiment, using the first opcode in the transition frame includes using the first opcode to determine that the transition frame is associated with the static initializer. In another embodiment, the method further includes causing the static initializer to run, wherein the static initializer using a second opcode, and resuming execution at the second opcode after the static initializer has run.
摘要:
A vehicle is disclosed which is normally supported by a plurality of wheels and tires, the vehicle having an article carrying space, with a floor formed of a first material and having an opening. A spare wheel and tire storage well is mounted in the opening through the floor and is formed of a second material different from the first material. The storage well is configured to accommodate a spare wheel and tire substantially equal in width and diameter to at least one of the plurality of wheels and tires supporting the vehicle. Also disclosed is a method for modifying a vehicle to carry a full size spare wheel and tire, including removing a portion of the floor of the vehicle, which portion includes a first storage well, to form an opening in the floor, placing a second storage well in the opening in the floor, the second storage well being configured and to accommodate a full size spare wheel and tire having a maximum width and diameter substantially equal to at least one of the wheels and tires normally supporting the vehicle such that a major portion of a maximum width of the full size spare wheel and tire is located below an upper surface of the floor, and attaching the second storage well to the floor. A lifting mechanism is disclosed to assist in the removal of the spare wheel and tire from the storage well. A force generating mechanism raises the spare wheel and tire when a securing device is removed.
摘要:
A vehicle is disclosed which is normally supported by a plurality of wheels and tires, the vehicle having an article carrying space, with a floor formed of a first material and having an opening. A spare wheel and tire storage well is mounted in the opening through the floor and is formed of a second material different from the first material. The storage well is configured to accommodate a spare wheel and tire substantially equal in width and diameter to at least one of the plurality of wheels and tires supporting the vehicle. Also disclosed is a method for modifying a vehicle to carry a full size spare wheel and tire, including removing a portion of the floor of the vehicle, which portion includes a first storage well, to form an opening in the floor, placing a second storage well in the opening in the floor, the second storage well being configured to accommodate a full size spare wheel and tire having a maximum width and diameter substantially equal to at least one of the wheels and tires normally supporting the vehicle such that a major portion of a maximum width of the full size spare wheel and tire is located below an upper surface of the floor, and attaching the second storage well to the floor. A lifting mechanism is disclosed to assist in the removal of the spare wheel and tire from the storage well. A force generating mechanism raises the spare wheel and tire when a securing device is removed.
摘要:
A grasping device for retaining an article includes a carriage extending in a loop between opposing ends with the carriage defining an opening. A jaw extends from each of the ends and away from the carriage to a respective tip for retaining the article between the jaws. The carriage is spring biased such that application of force to the carriage moves the ends and the jaws away from one another to release the article. Likewise, eliminating the force applied to the carriage moves the ends and the jaws toward one another to retain the article. A fastener extends from the grasping device for attaching the grasping device to a surface. The fastener includes a pin for attaching the grasping device to a surface and the fastener is rotatably connected to the carriage for rotating the fastener between an extended and a retracted position.