Tagged pointer handling apparatus is provided for implementation in a computer system wherein a tag bit is provided for each word in main storage. This invention provides for the mixing of data and pointers within the same storage space, and provides a capability for checking and verifying the validity of the pointers without affecting the performance or operation of other instructions. Only the tag instructions can set the tag bits ON in main storage; all other instructions store data and set the corresponding tag bits OFF. Thus, if a pointer was modified inadvertently by one of these data handling instructions, the fact that the pointer is untagged is detected and the values in the pointer are treated as invalid when the pointer is used by the Load and Verify Tags instruction. Instructions to load, store, set, move, extract and insert tags are implemented by the tagged pointer handling apparatus. A Load and Verify Tags instruction checks the validity of the pointer and if valid, loads the pointer into a specified general purpose register. A Store and Set Tags instruction stores the value in a specified general purpose register into main storage and sets the associated tag bits ON. A Move and Set Tags instruction moves a word from one location in main storage to another or the same location in main storage and sets the associated tag bits ON. A Move Characters and Tags instruction moves a word and the associated tag bits from one storage location to another storage location. An Extract Tags instruction fetches each word from an operand in main storage, extracts the tag bits, compresses the tag bits to one tag bit per quadword, and stores the tag bits in main storage as data. An Insert Tags instruction fetches the tag bits stored in main storage as data, expands the tag bits to one tag bit per word, and inserts them on each associated word of an operand in main storage.
A data processor for execution of tagged data and tagless data has a decoder for discriminating whether the data is tagged or tagless one and in case of a tagged data, separates a tag part and uses the remaining part for address computation. The data processor also comprises a unit for evaluating the tag part and a micro program controller for multi-branching in accordance with the evaluation result of the tag part. The tag evaluating unit includes an extender eliminating part for extracting the tag part from data on a data bus, a plurality of tag part storing registers for storing the tag part from the eliminating part under the control of the micro program controller, and a tag multi-way jump encoder for generating a tag multi-way jump address to feed it to the controller on the basis of the outputs of the registers and a signal from the micro program controller, thereby enabling tag multi-way jump.
A processor capable of processing data of a structure having a first information field and a second information field includes conservation means for conserving the information of the predetermined second information field of the input data. Thus, in executing a logical operation or a shift operation, the step of separating the first data fields and second data fields from the data to-be-processed and the step of affixing the predetermined second field to the result of the operation are dispensed with, thereby to achieve a high-speed operation for the data of the structure having the first information field and the second information field.
A multiprocessor system having shared memory uses guarded pointers to identify protected segments of memory and permitted access to a location specified by the guarded pointer. Modification of pointers is restricted by the hardware system to limit access to memory segments and to limit operations which can be performed within the memory segments. Global address translation is based on grouping of pages which may be stored across multiple nodes. The page groups are identified in the global translation of each node and, with the virtual address, identify a node in which data is stored. Pages are subdivided into blocks and block status flags are stored for each page. The block status flags indicate whether a memory location may be read or written into at a particular node and indicate to a home node whether a remote node has written new data into a location.
A multiprocessor system having shared memory uses guarded pointers to identify protected segments of memory and permitted access to a location specified by the guarded pointer. Modification of pointers is restricted by the hardware system to limit access to memory segments and to limit operations which can be performed within the memory segments. Global address translation is based on grouping of pages which may be stored across multiple nodes. The page groups are identified in the global translation of each node and, with the virtual address, identify a node in which data is stored. Pages are subdivided into blocks and block status flags are stored for each page. The block status flags indicate whether a memory location may be read or written into at a particular node and indicate to a home node whether a remote node has written new data into a location.
A RICS microprocessor architecture is provided with a plurality of data registers and instruction registers each having a multi-bit extension for extending the width of the data and instruction words processed therethrough. A first plurality of bits within a tag field of the multi-bit extension are reserved for identifying the data type of the data words while a second plurality of bits provide instruction dependent control. The multi-bit extension allows full precision computation for the data words requiring the tag field to identify the data type thereof while retaining full precision compatibility for data words not needing tag field identifiers. At least two bits of the first plurality of bits in tag field are reserved for identifying one of several primary categories of data types and at least two bits identify one of several subtype categories within each of the plurality of primary categories. An extended set of machine instructions is also provided for efficient usage of the multi-bit extension appended to the data and instruction registers.
