Abstract: Objects that are managed within a run-time environment are stored on N-bit aligned addresses. Due to the alignment restriction, the N least significant bits of a reference to an object are available for storing information about the storage properties of the object. This information is extractable by fast register operations. The storage properties can include the lifetime, format, and contiguity of the object, or a combination of these properties. If the run-time environment implements a generational garbage collector, the reference tags are used to encode whether or not the object is recently allocated.

Abstract: Objects that are managed within a run-time environment are stored on N-bit aligned addresses. Due to the alignment restriction, the N least significant bits of a reference to an object are available for storing information about the storage properties of the object. This information is extractable by fast register operations. The storage properties can include the lifetime, format, and contiguity of the object, or a combination of these properties. If the run-time environment implements a generational garbage collector, the reference tags are used to encode whether or not the object is recently allocated.

Abstract: In a paged memory system, memory is allocated as pages and aligned on 2N-byte boundaries that are at least as large as the largest page size. Memory management information about the page is stored in a page header at the beginning of the page, while the remaining space of the page is devoted for storing objects. The page header for the page on which at least some of the object is stored is located by masking off the lower N-bits of the machine pointer. These operation can be applied to converting machine pointers into and out of page-offset numeric references.

Abstract: A method and apparatus for copying garbage collection is described. A set of ambiguously referenced objects is identified in a from-space. Live objects in the from-space which are not ambiguously referenced are moved to the to-space, and the ambiguously referenced are transfixed (i.e. left behind to reside in the from-space). The boundaries of the ambiguously referenced are determined. When moving objects to the to-space, the objects are moved into regions between boundaries of objects transfixed in the to-space.

Abstract: A fast division technique is provided to calculate the address of a slot in a paged object, when the slot is located on a different page than the beginning of the object. The fast division technique employs arithmetical-logical operations of shifting and masking, that are faster than most hardware implementations of integer division and modulus, respectively. In one aspect, the use of these operations is facilitated by requiring the page size and the size of the page header to be a power of two.

Abstract: Techniques are provided for accessing an instance of a recreatable object in a shorter-duration memory based on a reference located in a longer-duration memory, where the shorter-duration memory is associated with a call. One technique involves (1) locating, within the shorter-duration memory, a context structure associated with the call; (2) locating an XREF pointers array based on data cached within the context structure; (3) determining whether the XREF pointers array includes a pointer associated with the reference; and (4) if the XREF pointers array includes a pointer associated with the reference, then following the pointer to locate the instance within the shorter-duration memory.

Abstract: A method and apparatus for performing copying garbage collection is provided. In a computer's memory, objects are stored in a permanent semispace. When a garbage collection event is detected, a garbage collection cycle is commenced. During the garbage collection cycle, the live objects in the permanent semispace are copied into a temporary semispace. After copying all the live objects into the temporary semispace, the live objects are then recopied into the permanent semispace.