Abstract: The present invention relates to an automated method and system for transforming a hardware test-case within a system level into at least one unit test-case for a functional unit within a unit level, wherein the functional unit is a component of said hardware. The method comprises the steps of emulating a model of the hardware in the system level, applying the hardware test-case for the system level, recognizing and selecting an information relevant for the functional unit, transforming the information into commands for the functional unit and outputting the unit test-case for the functional unit.

Abstract: A method, system, and computer program product for implementing a dual-addressable cache is provided. The method includes adding fields for indirect indices to each congruence class provided in a cache directory. The cache directory is indexed by primary addresses. In response to a request for a primary address based upon a known secondary address corresponding to the primary address, the method also includes generating an index for the secondary address, and inserting or updating one of the indirect indices into one of the fields for a congruence class relating to the secondary address. The indirect index is assigned a value of a virtual index corresponding to the primary address. The method further includes searching congruence classes of each of the indirect indices for the secondary address.

Abstract: An instruction is provided to perform clearing of selected address translation buffer entries (TLB entries) associated with a particular address space, such as segments of storage or regions of storage. The buffer entries related to segment table entries or region table entries or ASCE addresses. The instruction can be implemented by software emulation, hardware, firmware or some combination thereof.

Abstract: Selected units of storage, such as segments of storage or regions of storage, may be invalidated. The invalidation is facilitated by the setting of invalidation indicators located in data structure entries corresponding to the units of storage to be invalidated. Additionally, buffer entries associated with the invalidated units of storage or other chosen units of storage may be cleared. An instruction is provided to perform the invalidation and clearing. The instruction can be implemented by software emulation, hardware, firmware or some combination thereof.

Abstract: The present invention relates to a central processing unit comprising: (a) a number of functional units (A, B, . . . , N), (b) at least one module for processing of a function call received from one of the functional units, the module having a decoder to obtain an instruction address from the function call, a memory for storing a plurality of control instructions and for storing a plurality of branch instructions, each control instruction having an assigned instruction address for a next instruction and each branch instruction having assigned at least two alternative instruction addresses for a next instruction, first logic circuitry for processing of the branch instructions in order to select one of the at least two alternative instruction addresses of one of the branch instructions, second logic circuitry for processing of the control instructions in order to return a result in response to the function call.

Abstract: The present invention generally relates to shared-memory multiprocessor systems, such as IBM ESA/390 or RS/6000 systems, and deals more particularly with a method and system for sharing a second-level translation lookaside buffer (TLB 2) between several CPUs (30a, . . . 30d) for improving the performance and reducing the chip area required to buffer the results of virtual-to-absolute address translations. The inventive TLB2 organization comprises several small arrays (32a, . . . 32d) dedicated to particular CPUs, providing an interface to a major array (21), which is shared between the CPUs. The dedicated arrays 32a, . . . 32d) are required to fulfill the architected constraints and link several CPUs to the commonly used shared array (21).

Abstract: A process is provided for monitoring the conversion of numerical values from a first to a second format, where before and after the conversion, the modulo residue of the corresponding numerical value is calculated and compared with the corresponding residue after the conversion. In this way it is possible to effect error-free monitoring of such a conversion, especially of computer data, without great hardware expenditure.

Abstract: The present invention generally relates to shared-memory multiprocessor systems, such as IBM ESA/390 or RS/6000 systems, and deals more particularly with a method and system for sharing a second-level translation lookaside buffer (TLB 2) between several CPUs (30a, . . . 30d) for improving the performance and reducing the chip area required to buffer the results of virtual-to-absolute address translations. The inventive TLB2 organization comprises several small arrays (32a, . . . 32d) dedicated to particular CPUs, providing an interface to a major array (21), which is shared between the CPUs. The dedicated arrays 32a, . . . 32d) are required to fulfill the architected constraints and link several CPUs to the commonly used shared array (21).

Abstract: The basic idea comprised of the present invention is to provide a translation lookaside buffer (TLB) arrangement which advantageously uses two buffers, a small first level TLB1 and a larger second level TLB2. The second level TLB feeds address information to the first level TLB when the desired virtual address is not contained in the first level TLB. According to the invention the second level TLB is structured advantageously comprising two n-way set-associative sub-units of which one, a higher level unit covers some higher level address translation levels and the other one, a lower level unit, covers some lower level translation level. According to the present invention, some address information holds some number of middle level virtual address (MLVA) bits, i.e., 8 bits, for example, being able to serve as an index address covering the address range of the higher level sub-unit.

Abstract: A method and system for renaming registers of said system is proposed in which mixed instruction sets, e.g. 32 bit and 64 bit instructions are carried out concurrently in one program. In case of an instruction sequence of a preceding 64 bit instruction and one or more 32 bit instructions to be executed in-order after the 64 bit instruction and where the 32 bit instructions having a data dependence to the preceding 64 bit instruction, said rest of the register range changed by the preceding 64 bit instruction is copied to the corresponding location in a target register of the succeeding 32 bit instruction, at least if the same logical register is specified by the 32 bit instruction as it was specified by the preceding 64 bit instruction. The copy source is addressed by the register number and hold in a list (28).

Abstract: A system and method for register renaming and allocation in an out-of-order processing system which allows the use of a minimum number of physical registers is described. A link list allows concatenation of a physical register representing a certain instance of the corresponding logical register to the physical register representing the next instance of the same logical register. By adding and removing links in this link list, it is possible to manage the assignment of physical registers to logical registers dynamically. Both the physical registers representing speculative instances and the physical registers representing in-order instances are administrated together. This is done by means of an in-order list, which indicates the physical registers that actually represent the architected state of the machine.

Abstract: A set of storage devices together with a method for storing data to the storage devices and retrieving data from the storage devices is presented. The set of storage devices provide the function of a multi-writeport cell through the use of a set of single-writeport cells. The storage devices allow for multiple write accesses. Information contained in the set of storage device is represented by all of the devices together. The stored information may be retrieved via a read operation which accesses a subset of the set of storage devices. A write operation is a staged operation: First, the contents of all of the storage devices which are not to be modified are read. Next, the values that are to be written to a subset B of the set of storage devices are calculated in a way that the contents and the values of subset B together represent the desired result.

Abstract: The invention relates to the area of register renaming and allocation in superscalar computer systems. When a multitude of instructions in the instruction stream reads from or writes to a certain logical register, said logical register will have to be represented by a multitude of physical registers.Therefore, there have to exist several physical rename registers per logical register. The oldest one of said rename registers defines the architected state of the computer system, the in-order state.The invention provides a method for administration of the various register instances. Both the registers representing the in-order state and the various rename instances are kept in one common circular buffer. There exist two pointers per logical register: The first one, the in-order pointer, points to the register that represents the in-order state, the second one, the rename pointer, points to the most recent rename instance.

Abstract: A shifting structure and method which separates a shifting operation into partial shifts which may be executed in different pipeline staged is described herein. In a first pipe stage, an operand is read out and at least one partial shift is accomplished by placing the operand or parts thereof into registers coupled to a shift unit. The shift unit, in a second pipe stage, finalizes the shifting operation executing the remaining partial shifts, thereby reducing the time required for the total shifting operation. A control string is derived in the shift unit based on the shift amount to correct the output of the shifted result as well as providing for parity prediction therefor.

Abstract: A process is disclosed to serialize instructions that are to be processed serially in a multiprocessor system, with the use of a token, where the token can be assigned on request to one of the processors, which thereupon has the right to execute the command. If the command consists of dristibuted tasks, the token remains blocked until the last dependent task belonging to the command has also been executed. It is only then that the token can be assigned to another instruction. Moreover, a device is described to manage this token, which features three states: a first state, in which the token is available, a second state, in which the token is assigned to one of the processors, and a third state, in which the token is blocked, because dependent tasks still have to be carried out. Moreover, a circuit is disclosed with which the token principle that is introduced can be implemented in a simple manner.

Abstract: In this circuit, video signals with a continuously increasing or decreasing amplitude are applied to the signal input of a threshold difference comparator at whose reference inputs selectively determined high and low threshold signals are applied. The output of the threshold difference comparator is applied at the first input of a threshold AND gate having a second input connected to a clock. The output of the threshold AND gate supplies a clock pulse sequence which has a duration corresponding with the time during which the input video signal has an amplitude which continuously increases or decreases from one of the threshold reference amplitudes to the other. The clock pulse sequences contained in successive measuring intervals have their respective pulses counted by a counter, and are stored in a buffer. A measurement series is performed corresponding to different focus settings, optimum focus adjustment being achieved when a minimum count of clock pulses in a clock pulse sequence is obtained.

Abstract: Method and apparatus for automatic optical inspection of a substantially two-dimensional pattern using digital image processing techniques are described. In a first processing step, all regions of a digitized stored image derived from the two-dimensional pattern are scanned for edges or lines, that is, transitions between regions having optically different characteristics. The scanned edge regions are marked in the image storage. In a subsequent second processing step all non-marked regions of the image storage are scanned and tested for the presence of permissible grey levels. A meander-shaped scanning track is used for scanning the edge or lined regions. The apparatus for implementing this method includes special latch circuitry for eliminating the further processing of marked regions, thus increasing the overall speed at which the two-dimensional pattern can be optically inspected.