Abstract: The present invention generally relates to an apparatus and method for efficiently translating virtual addresses utilizing either single address space or multiple address space models in a virtual memory management system. In particular, a Virtual Hash Page Table (VHPT), an extension of the Translation Lookaside Buffer (TLB) hierarchy, is designed to enhance virtual address translation performance. Virtual Hash Page Table (VHPT) efficiently supports two different methods of operating systems use to translate virtual addresses to physical addresses. This directly benefits the highly frequented path of address resolution.

Abstract: A method and apparatus pre-validate regions in a virtual addressing scheme by storing both the virtual region number (VRN) bits and region identifiers (RIDs) in translation lookaside buffer (TLB) entries. By storing both the VRN bits and RIDs in TLB entries, the region registers can be bypassed when performing most TLB accesses, thereby removing region registers the critical path of the TLB look-up process and enhancing system performance. A TLB in accordance with the present invention includes entries having a valid field, a region pre-validation valid (rpV) field, a virtual region number (VRN) field, a virtual page number (VPN) field, a region identifier (RID) field, a protection and access attributes field, and a physical page number (PPN) field. In addition, a set of region registers contains the RIDs that are active at any given time.

Abstract: A method and apparatus calculate a page table index from a virtual address. Employs a combined hash algorithm that supports two different hash page table configurations. A “short format” page table is provided for each virtual region, is linear, has a linear entry for each translation in the region, and does not store tags or chain links. A single “long format” page table is provided for the entire system, supports chained segments, and includes hash tag fields. The method of the present invention forms an entry address from a virtual address, with the entry address referencing an entry of the page table. To form the entry address, first a hash page number is formed from the virtual address by shifting the virtual address right based on the page size of the region of the virtual address.

Abstract: A method and apparatus pre-validate regions in a virtual addressing scheme by storing both the virtual region number (VRN) bits and region identifiers (RIDs) in translation lookaside buffer (TLB) entries. By storing both the VRN bits and RIDs in TLB entries, the region registers can be bypassed when performing most TLB accesses, thereby removing region registers the critical path of the TLB look-up process and enhancing system performance. A TLB in accordance with the present invention includes entries having a valid field, a region pre-validation valid (rpV) field, a virtual region number (VRN) field, a virtual page number (VPN) field, a region identifier (RID) field, a protection and access attributes field, and a physical page number (PPN) field. In addition, a set of region registers contains the RIDs that are active at any given time.

Abstract: A computer apparatus incorporating special instructions to force load and store operations to execute in program order. The present invention provides a new and novel store instruction that is suspended until all prior store instructions have been completed by an associated CPU. Also, a new load instruction is provided which blocks any subsequent load instructions from executing until this load instruction has been completed by an associated CPU. These instructions allow for high efficiency computer systems to be implemented which optimize instruction throughput by executing subsequent instructions while waiting for a prior instruction to complete.

Abstract: A method and apparatus pre-validate regions in a virtual addressing scheme by storing both the virtual region number (VRN) bits and region identifiers (RIDs) in translation lookaside buffer (TLB) entries. By storing both the VRN bits and RIDs in TLB entries, the region registers can be bypassed when performing most TLB accesses, thereby removing region registers the critical path of the TLB look-up process and enhancing system performance. A TLB in accordance with the present invention includes entries having a valid field, a region pre-validation valid (rpV) field, a virtual region number (VRN) field, a virtual page number (VPN) field, a region identifier (RID) field, a protection and access attributes field, and a physical page number (PPN) field. In addition, a set of region registers contains the RIDs that are active at any given time.

Abstract: The present invention generally relates to an apparatus and method for efficiently translating virtual addresses utilizing either single address space or multiple address space models in a virtual memory management system. In particular, a Virtual Hash Page Table (VHPT), an extension of the Translation Lookaside Buffer (TLB) hierarchy, is designed to enhance virtual address translation performance. Virtual Hash Page Table (VHPT) efficiently supports two different methods of operating systems use to translate virtual addresses to physical addresses. This directly benefits the highly frequented path of address resolution.

Abstract: A method and apparatus for transferring data from a first memory location to a second memory location in a computer system. A load instruction is executed, and, in response, data is transferred from a first memory location to a second memory location during a single bus transaction. During the same bus transaction, a request is made to invalidate a copy of the data that is stored in a third memory location if the load instruction indicates to do so.

Abstract: Apparatus and method for efficiently sharing data in support of hardware he coherency and coordinated in software with semaphore instructions. Accordingly, a new instruction called "Load-Bias" which, in addition to normal load operations, requests a private copy of the data, and hints to the hardware cache to try to maintain ownership until the next memory reference from that processor. When used with the Cmpxchg instruction semaphore operation, the Load-Bias instruction will reduce coherency traffic, and minimize the possibility of coherency ping-ponging or system deadlock that causes the condition in which no processor is getting useful work done.

Abstract: A computer apparatus which detects a store or load operation into or from a shared memory page by a program that does not provide for synchronization when executed by a CPU that completes instructions out of program order. After the store or load is detected, the CPU explicitly orders operations into the shared memory page. Store operations are ordered such that no new store into the shared memory page is performed until all prior store operations into the shared memory page are complete. Also, load operations are ordered such that load operations from the shared memory page are performed in program order. This ordering is achieved by maintaining a process bit and a memory attribute bit associated with a shared memory page. When both bits are true, all load or store operations referencing the shared memory page are ordered.

Abstract: A translation lookaside buffer (TLB) is provided including a first storage location in the TLB for storing at least a portion of a first virtual to physical memory translation. The first storage location in the TLB is both hardware-managed and software-managed. The TLB also includes a second storage location in the TLB for storing at least a portion of a second virtual to physical memory translation. The second storage location in the TLB is only software-managed.

Abstract: The inventive system and method allows for software control of hardware drral of exceptions in speculative operations, and comprises three components. The first component is processor stored information which reflects the code generation strategy of applications and is used by hardware and the operating system to control exception deferral. The second component is processor stored information set by the operating system to specify to hardware which type of faults should be automatically deferred. The third component is further processor stored information which indicates to the hardware to defer certain exception causing aspects of the speculative operation, while performing other non excepting aspects of the speculative operation. The stored information is set after the operating system exception handler has unsuccessfully attempted fault resolution.

Abstract: A computing system includes a memory bus, an input/output bus, a main memory, and an input/output adapter. The memory bus provides information transfer. The input/output bus also provides information transfer. For example the input/output bus is an input/output bus onto which is connected input/output devices. The main memory is connected to the memory bus. The main memory includes a page directory. The page directory stores translations. Each translation in the page directory includes a portion of an address for data transferred over the input/output bus, for example, the page address portion of I/O bus address. Each translation in the page directory also is indexed by a portion of an address for a memory location within the main memory, for example, the page address portion of the address for the memory location. The input/output adapter is connected to the memory bus and the input/output bus. The input/output adapter includes an input/output translation look-aside buffer.

Abstract: A computing system includes a main memory and an input/output adapter. The input/output adapter accesses a translation map. The translation map maps input/output page numbers to memory address page numbers. Entries to the translation map are generated so that each entry includes an address of a data page in the main memory and transaction configuration information. The transaction configuration information is utilized by the input/output adapter during data transactions to and from the data page.

Abstract: A computing system includes a memory bus, a main memory, an I/O adapter and a processor. The main memory, the I/O adapter and the processor are connected to the bus. The I/O adapter includes a translation map. The translation map maps I/O page numbers to memory address page numbers. The translation map includes coherence indices. The processor includes a cache and an instruction execution means. The instruction execution means generates coherence indices to be stored in the translation map. The instruction execution means performs in hardware a hash operation to generate the coherence indices.

Abstract: A method for operating a digital computer in response to the occurrence of an exception is disclosed. The method provides for the examination both of the contents of a predetermined computer location and of the instruction code for the instruction causing the exception. The computer then utilizes the result of those examinations to determine the dismissibility of the exception. The computer transfers control to the next instruction after the instruction which caused the exception if that instruction is dismissible.