Abstract: A multichannel data path architecture which assists a host processor in communication with the frame buffer in order to increase the overall system performance. The architecture provides automatic frame buffer data path rearrangement depending on the pixel address and the host data interpretation. It utilizes a minimum of shift registers, accumulators and control circuitry to provide the requisite storage, reconfiguration and frame buffer access functions. The architecture extends bit-blt (bit block transfer) conventional operations in order to provide high quality "antialiased" text and graphics directly in the architecture without requiring the calculation of colors by the host processor. Finally, it assists the "burst" mode update of an arbitrary single plane of a frame buffer, which is especially important when high denisty chips are used for the frame buffer implemenation.

Abstract: A vector generator for us with an all-points-addressable frame buffer capable of the non-word aligned access, simultaneously, of a square M by N array of pixels providing fast vector drawing independently of vector slope and position in the whole screen area of an attached display monitor. The vector generator utilizes a triangular logic matrix together with a line drawing unit to generate M vector bits lying in an M by N square matrix of the screen of an attached monitor in one memory cycle of the frame buffer and uses the generated matrix to generate a direct mask for the frame buffer whereby the M bit vector may be stored in a single memory cycle.

Abstract: A procedure for use in an optimizing compiler termed "reassociation" determines the preferred order of combining terms in a sum so as to produce loop invariant subcomputations, or to promote common subexpressions among several essential computations, by applying the associative law of addition. To achieve this, the requisite optimization of an object program or program segment, the following discrete steps must be performed after the strongly connected regions, USE and DEF chains have all been identified:1. Find the region constants and induction variables;2. Identify all of the essential computations;3. Write every essential computation as a sum of products;4. Exploit the use and DEF functions to substitute the definition of each operand R in an essential computation, if there is a unique computation of R in the strongly connected region and the defining operation is +, -, .times., or copy;5. Fix displacements;6.

Abstract: A data processing system is provided which includes ALU data busses, temporary operand storage registers, an accumulator, and a set of latches for temporarily storing data to be supplied to the input of the ALU. Output multiplexer is provided which can select the output of one of the latches or that of the ALU which is sent to the accumulator. A detector is also provided for determining whether the smaller or larger one of two data elements is stored in said latches according to the status of the ALU and a new MIN/MAX instruction and the selected data element is returned to a predetermined temporary storage register via the output multiplexer. A controller operates in cooperation with the system instruction decoder to effect this operation with a single machine instruction.

Abstract: A method for improving the quality of code generated by a compiler or assembler, for a target machine that has short and long forms of some of its instructions with the short forms executing faster or occupying less space. The method first determines which bits of the result of each computational instruction are significant, by a backwards pass over the program that is similar to liveness analysis. Then the significant bits thus computed are used to guide the code selection process to select the most efficient instruction that computes the correct result in all the significant bit positions.

Abstract: A method for modeling complementary metal oxide semiconductor (CMOS) combinatorial logic circuits by Boolean gates taking into account circuit behavior effects due to charge storing and static hazards. Models are developed for both the faultless and faulty operation of each circuit. According to a further aspect of the invention, these models are used in a simulation procedure to evaluate the fault coverage of a large scale integrated circuit design built using a plurality of these circuits. In the evaluation procedure the faulty model is used only for a particular circuit whose failure performance is being tested and the faultless model is utilized for all other circuits. This procedure is continued until all of the individual gate circuits have been evaluated.

Abstract: A method for increasing the wirability of complementary metal oxide semiconductor (CMOS) differential cascode voltage switch (DCVS) logic circuits which comprises designing the circuitry to permit as many of the internal tree connections as possible to be wired using diffusion techniques. The method utilizes differential pair and load microblocks which have been designed so as to allow mirroring on a vertical center line. Utilizing the availability of mirroring for individual pairs plus relocation of individual pairs in the logic tree the crossings may be largely eliminated in a shortened period. It utilizes a step by step row and column analysis of the initial or starting tree design resulting from the basic Boolean logic to be performed by the particular circuit and makes required load mirroring and differential pair relocation decisions in an iterative process. The transistor pairs and load devices may be mirrored about a vertical center line.

Abstract: A hierarchical memory system for use with a high speed data processor characterized by having separate dedicated cache memories for storing data and instructions and further characterized by each cache having a unique cache directory containing a plurality of control bits for assisting line replacement within the individual cache memories and for eliminating many accesses to main memory and to insure that unnecessary or incorrect data is never stored back into said main memory.The present cache architecture and control features render broadcasting between the data cache and instruction cache unnecessary. Modification of the instruction cache is not permitted. Accordingly, control bits indicating a modification in the cache directory for the instruction cache are not necessary and similarly it is never necessary to store instruction cache lines back into main memory since their modification is not permitted.

Abstract: The inspection of the walls of a deep hole of minute diameter in a structure such as an integrated circuit board is carried out by inserting into the hole a reflective optical sphere having a diameter at least slightly smaller than the hole diameter. A coated optical fiber having a diameter substantially less than the diameter of the sphere has one end attached to the sphere. An optical scattering means is interposed between the sphere and the fiber to disperse illumination from the optic fiber to illuminate the walls of the hole. A source of illumination is provided at the opposite end of the optic fiber, and an optical system is positioned axially at the end of the hole to pick up the image of the illuminated walls reflected from the sphere.

Abstract: A branch target table (10) is used as an instruction memory which is referenced by the addresses of instructions which are targets of branches. The branch target table consists of a target address table (12), a next fetch address table (14), valid entries table (16) and an instruction table (18). Whenever a branch is taken, some of the bits in the untranslated part of the address of the target instruction, i.e. the instruction being branched to, are used to address a line of the branch target table (10). In parallel with address translation, all entries of the branch target table line are accessed, and the translated address is compared to the target address table (12) entry on that line.

Abstract: The programmable logic controller uses a set of instructions which comprises only three instructions: a Read instruction and a Write instruction which includes an operation code, a condition bit, and an address, and a Jump instruction which includes an operation code and an address. When a Read instruction is read from control memory (10), a condition latch (35) is set to 1 or 0 depending on whether the level of the addressed input corresponds or not to the level of the condition bit. For a Write operation, the state of latch (35) or its inverse is provided at the addressed output in accordance with the value of the condition bit. A Jump instruction is executed only if the condition latch (35) is set to 1. A random access memory (50) may be utilized to function as one of the input multiplexers (RI0 to RI2) and one of the output demultiplexers (RO0 to RO2), which allows the controller to store events and to use said events later on.

Abstract: A display architecture is disclosed which supports a variable, selectable number of bits per chip and a variable, selectable segment width. The architecture comprises a plurality of dynamic memory chips and a function generator. Each of the memory chips includes at least two data islands wherein each data island has its own data in/out line, chip select and increment bit supplied by the function generator. The function generator receives a starting address X.sub.o, Y.sub.o, the data path width N.sub.D and an encoded segment width S. A bit incrementer in the function generator generates increment bits A.sub.I based on the externally supplied modulo N.sub.D. The function generator generates the physical word address w.sub.o and physical bit address b.sub.o based on the starting address X.sub.o, Y.sub.o, the data path width N.sub.D and the encoded segment width S. Logic circuitry is provided which is responsive to an overflow bit produced by the bit incrementer to control spill and wrap functions.

Abstract: A method for use during the optimizatin phase of an optimizing compiler for performing global common subexpression elimination and code motion which comprises:Determining the code `basis` for the object program which includes examining each basic block of code and determining the `basis` items on which each computation depends wherein `basis` items are defined as operands which are referenced in a basic block before being computed. The method next determines the "kill set" for each `basis` item. Following this UEX, DEX, and THRU are determined for each basic block using the previously determined `basis` and "kill set" information. AVAIL and INSERT are computed from UEX, DEX, and THRU, and appropriate code insertions are made at those locations indicated by the preceding step, and finally redundant code is removed using the AVAIL set.

Abstract: A method for improving the quality of code generated by a compiler in terms of execution time, object code space, or both. The method is applicable to computers that have a redundancy of instructions, in that the same operation exists in forms that operate between registers, between main storage locations, and between registers and main storage. The method selects the best form of each such instruction to use, for the context in which the instruction lies.

Abstract: An electrochromic matrix display of the kind in which the display electrodes are supported on a substrate above a corresponding matrix of transistor switches employs constant current writing and potentiostatic erasure. The transistors are switchable by signals applied on respective gate lines to pass electric current on the respective drive lines to their display electrodes. Gate and drive selection means define the active gate and drive lines During erasure, the potentiostatic erase voltage is applied to both ends of the selected drive lines simultaneously to speed up the current limited asynchronous erase operation. Optionally, the display may be driven alternately from opposite ends of the drive lines during a line-by-line writing operation.

Abstract: The system includes a plurality of memory units each for storing a plurality of independently addressable binary bits. The units operate together in response to each common bit address to supply a bit from each unit to form an array of bits for a discrete section of a larger array. The units are interconnected through common interconnection buses and selectively actuable input and output gate connections to those buses to provide for selective shifting of bits between units to change the bit array.

Abstract: A method operable within an optimizing compiler to move certain range check instructions out of single entry strongly connected regions or loops and into linear regions of the instruction stream whereby computational efficiency is increased with no loss of program accuracy. The method comprises placing a range check trap instruction into the header node of the SCR provided there is only one conditional exit from the SCR, modifying the conditional exit test based on the value of the induction variable v, and inserting a new check at the loop exit point(s) to insure that the induction variable has reached the value it would have obtained in the original (unmodified) program.

Abstract: A method operable within an optimizing compiler for generating Basis items and Kill Sets for use during subsequent global common subexpressions elimination and code motion procedures. More particularly, the method comprises assigning a symbolic register to each non-basis element to be computed as follows: creating a tuple (v) for each computation which is to be converted to a machine instruction by the compiler creating a table (optimally, a hash table) having an entry for all the tuples in the program being compiled; for every Basis element in a tuple being entered in the table a symbolic register uniquely assigned to that tuple is added to the Kill Set for that Basis element. For every non-basis element "n" in the tuple being entered into the table, the uniquely assigned symbolic register for that tuple is added to the Kill Sets for all the Basis elements in whose Kill Sets that non-basis element "n" appears.

Abstract: A metallic hollow cathode electrode structure for use in a RF-RIE sputter/etch system. The electrode defines a critical aspect ratio hollow cathode volume. In accordance with one embodiment of the invention, the electrode structure may consist of two closely spaced metal elements separated by a distance of a few centimeters. The elements are electrically and structurally connected by supports around their outer rim. An RF voltage is applied between the improved hollow cathode electrode structure and an evacuated chamber containing same through a suitable matching network. A plasma gas is supplied to the system from a point outside the electrodes and a suitable pumping system is used to maintain operating pressures in the 0.1 to 400 millitorr range. Samples to be sputtered are then placed on either of the inside electrode surfaces for sputter/etching. The aspect ratio (longest dimension of one of the elements/spacing between the elements) should be at least 4.

Abstract: A memory address translation and related control system for performing the dual functions of converting virtual memory addresses generated by the CPU into real memory addresses in a highly efficient and versatile manner and for controlling certain memory functions such as journalling. The address translation function comprises two steps, the first comprising converting the virtual address into a second virtual address or an effective address and finally the step of converting the effective address into a real memory address. The first step utilizes a set of special registers addressable by a small field to the CPU generated virtual address which converts the virtual address into an expanded form. The second or effective address is then used as the subject of the second or address translation step.