Abstract: A three input arithmetic logic unit (230) forms a mixed arithmetic and Boolean combination of three multibit input signals. The arithmetic logic unit (230) first forms a Boolean combination and then forms an arithmetic combination. The current instruction drives an instruction decoder (250, 245) that generates the functions signals F0-F7 which control the combination formed. The three input arithmetic logic unit (230) preferably employs a set of bit circuits (400), each forming carry propagate, generate and kill signals. These signals may employed with a multilevel logic tree circuit and a carry input to produce a bit resultant and a carry output to the next bit circuit. This structure permits formation of selected arithmetic, Boolean or mixed arithmetic and Boolean function of the three input signals based upon the current instruction. Selection of the function signals enables the combination to be insensitive to one of the input signals, thus performs a two input function of remaining input signals.

Abstract: This invention decodes a continuous stream of Huffman encoded data, each datum having a size portion of a predetermined number of bits and a value portion of a variable number of bits. The invention extracts the size portion, determines the variable number of bits of the value portion and extracts this value portion. The decoding of this value portion differs depending upon the sign bit. If this sign bit is "1", then translation is required. A mask constant having a single "1" bit is rotated an amount equal to the size aligning this single "1" bit with the most significant bit of the value portion. This rotated mask is ANDed with the value portion. A zero result indicates no translation is needed. The translation, if needed, takes place by subtraction. The quantity 2.sup.N -1 is subtracted from the value portion, where N is the size. A mask generator (239) forms the quantity 2.sup.N -1 by forming a number of right justified "1's" equal to the size.

Abstract: There is disclosed a multiprocessor system and method arranged, in one embodiment, as an image and graphics processor. The processor is structured with several individual processors all having communication links to several memories without restriction. A crossbar switch serves to establish the processor memory links and the entire image processor, including the individual processors, the crossbar switch and the memories, are contained on a single silicon chip.

Abstract: A three input arithmetic logic unit (230) forms a mixed arithmetic and Boolean combination of three multibit input signals. The arithmetic logic unit (230) first forms a Boolean combination and then forms an arithmetic combination. The current instruction drives an instruction decoder (250, 245) that generates the functions signals F0-F7 which control the combination formed. The arithmetic logic unit (230) includes a first three input Boolean function generator (496) forming a Boolean combination F1(A,B,C), a second three input Boolean function generator (497) forming a Boolean combination F2(A,B,C), and an adder (495) forming the sum of the two Boolean combinations. The first Boolean combination F1(A,B,C) and the second Boolean combination F2(A,B,C) are independently selected from the set of all possible Boolean combinations of three multibit input signals A, B and C. The adder (495) includes a least significant bit carry-in generator (246) supplying a carry input to the least significant bit.

Abstract: The graphics data processor of the present invention offers as a single instruction in its instruction set a draw and advance operation. A first data register stores a set of X and Y coordinates. In a first embodiment, a predetermined color code is stored at the pixel address of a bit mapped display memory indicated by the X and Y coordinates the first data register upon execution of the draw and advance instruction. The X and Y coordinates stored in the first data register are then advanced by addition of X and Y coordinates stored In a second data register. A second embodiment is similar except that the color code stored at the X and Y coordinates of the first data register is recalled for combining with the predetermined color code and the combined result stored at that pixel location. The predetermined color code is preferably stored in another data register.

Abstract: In a video-type computer system and the like, an improved memory circuit is provided for adapting the system to CRT screens having different resolutions. The memory circuit includes a bit-mapped RAM unit or chip having sufficient cells to accommodate any CRT screen sought to be used, and also a serial shift register having taps at a plurality of different locations corresponding to different columns of cells in the RAM unit. When the RAM unit is in serial mode, a row of data is transferred into the serial shift register. Then the column address applied to the RAM unit is used to instruct and actuate a suitable decoder circuit to select the tap appropriate to unload the portion of the serial shift register containing the data bits of interest.

Abstract: A method of computing a mean squared error between a predetermined plural number of pairs of first and second values employs a data processing apparatus (71, 72, 73, 74) having data registers (200), an arithmetic logic unit (230), a flags register (211), a multiplication unit (220), a source of instructions and an instruction decoder (245, 246, 250). The arithmetic logic unit (230) forms a difference between pairs. A status detector determines whether the result is less than zero. The flags register (211) stores status bits indicating this detected status. The arithmetic logic unit (230) conditionally either adds the difference to zero if the status bit indicates the difference was not less than zero or subtracts the difference from zero if the status bit indicated the difference was less than zero. The multiplication unit (220) forms the square. The square is added to a running sum. In an alternative embodiment, the arithmetic logic unit can perform operations upon data in separate sections.

Abstract: A processing system operating on data words having first and second portions includes a memory bank comprising first and second memories each with associated first and second set of address inputs. First memory includes a first storage location storing the first portion of a first word accessible by a set of address bits received at the first inputs and a second set of address bits received at the second inputs. The first memory further includes a second storage location storing the second portion of a second word accessible by the first set of bits received at the first inputs and a third set of bits received at the second inputs. Second memory includes a first storage location storing the second portion of the second word accessible by the first set of bits received at the first inputs and the second set of bits received at the second inputs.

Abstract: A synchronous random access memory is arranged to be responsive directly to a system clock signal for operating synchronously with the associated microprocessor. The synchronous random access memory is further arranged to either write-in or read out data in a synchronous burst operation or synchronous wrap operation in addition to synchronous random access operations. The synchronous random access memory device may be fabricated as a dynamic storage device or as a static storage device.

Abstract: The present invention is a graphics data processor which includes the capability of determining whether a defined pixel location in a graphics display is within a window in an X Y coordinate system. The respective X and Y coordinates of the selected pixel are separately compared with the window limits. The window limits are preferable expressed as the X and Y coordinates of two diagonally opposite vertexes of a rectangular window. The results of this comparison are preferable available in two forms. In a first embodiment a single data processing instruction enables the generation of a digital data word which indicates the relation of the pixel to the window. This digital word includes a separate indication of the relationship of the pixel to the vertical and horizontal window limits. This indication can be used to generate a "trivial rejection" in determining whether a line or line segment passes through the window by ANDing the results for two points on the line.

Abstract: There is disclosed a multiprocessor system arranged, in one embodiment, as an image and graphics processor. The processor is structured with several individual processors all having communication links to several memories without restriction. A crossbar switch serves to establish the processor memory links. The entire image processor, including the individual processors, the crossbar switch and the memories are contained on a single silicon chip. Each processor can operate to execute the same instruction at the same time (SIMD mode) or different instructions at the same time (MIMD mode).

Abstract: The graphics processing apparatus of the present invention utilizes individual registers of a register file to store the X and Y coordinates of pixels. These X and Y coordinates though formed into a single data word are separable by, for example, having the most significant bits specifying the Y coordinate and the least significant bits specifying the Y coordinate. The graphics processing apparatus supports instructions which provide separate and independent data manipulation of these X and Y coordinates. These X Y coordinate manipulation instructions can provide for separate X Y arithmetic operations on two data words, separate X and Y compare operations, separate X and Y data move operations and a conversion between the X Y address form to the linear address form. This technique is highly useful for manipulation of X Y address coordinates in a visual display system employing bit mapped graphics.

Abstract: A palette device controllable by a digital computer with a video memory having a bus for supplying multiple color codes for the palette device in each bus cycle. The palette device includes a multiple-bit input for entry of the color codes from the bus, and a look-up table memory for supplying color data words in response to the color codes from the input. Color code transfer circuitry is connected between the input and the look-up table memory to supply the look-up table memory from the input sequentially with color codes of selectable width packing the entire width of the bus. Improved palette devices, graphics computer systems, facsimile systems, printer systems and other systems and methods are also disclosed.

Abstract: The graphics data processor of the present invention offers as a single instruction in its instruction set a draw and advance operation. A first data register stores a set of X and Y coordinates. In a first embodiment, a predetermined color code is stored at the pixel address of a bit mapped display memory indicated by the X and Y coordinates the first data register upon execution of the the draw and advance instruction. The X and Y coordinates stored in the first data register are then advanced by addition of X and Y coordinates stored in a second data register. A second embodiment is similar except that the color code stored at the X and Y coordinates of the first date register is recalled for combining with the predetermined color code and the combined result stored at that pixel location. The predetermined color code is preferrably stored in another data register.

Abstract: A palette device for use with a digital computer that produces a video control signal and color code signals for a first bus and where the digital computer has a graphics coprocessor that produces a video control signal and color code signals for a second bus. The palette device includes an input register for holding respective bits from separate sets of input lines including a first set of input lines for signals representing color codes on the first bus and a second set of input lines for signals representing color codes on the second bus. The palette device further has a look-up table memory for supplying color data words in response to color codes from the input register, and a selector circuit connected between the input register and the look-up table memory. The selector circuit is externally controllable to transfer selected color codes from the selected first or second bus to said look-up table memory and to select a video control signal for output depending on the selected bus.

Abstract: The present invention presents a process of moving an array of pixel data representing an image to be displayed from a source memory space to a destination memory space. The array of pixel data is arranged in words containing a plurality of individual pixel datum. The process includes transforming each pixel datum in the word fetched from the source memory space to a colorized pixel datum by individually attaching color information to each pixel datum. The transforming occurs substantially in parallel on all of the pixel data in each word. This technique permits storage of commonly used images such as alphanumeric characters of various fonts or icons in a compressed form with one bit per pixel. These images are formed in color using the color expand operation at the time of drawing into the color display memory. Otherwise these images would need to be stored in multiple bit per pixel color form for all desired colors requiring considerable memory for redundant data.

Abstract: A palette device for use with circuitry that produces color codes and a video control signal. The palette device includes a mode circuit establishing one of a plurality of different operating modes, and color code processing circuitry operable according to a mode established by the mode circuit and responsive to the color codes to supply color data words that are convertible to analog form. Depending on the different modes, the color code processing circuitry establishes different time intervals between input of the color codes to the color code processing circuitry and supplying of color data words. A digital to analog converter connected to said color code processing circuitry receives the color data words and converts them to an analog video signal.

Abstract: An integrated circuit for use with a plurality of clock oscillators. The integrated circuit has a semiconductor chip, function performing circuitry fabricated on the semiconductor chip and responsive to clock pulses provided thereto, and a semiconductor chip package having pins connected to the function performing circuitry. The integrated circuit further has a register accessible via the pins for external entry of clock control information. A clock control circuit responsive to the clock control information entered in said register has inputs connected to pins for the clock oscillators. The function performing circuitry is connected to the clock control circuit so that clock pulses are provided to the function performing circuitry by the clock control circuit in accordance with the clock control information entered in the register. Other integrated circuits, palette devices, computer graphics systems, printer systems and methods are also disclosed.

Abstract: A graphics data processor which includes the capability of determining whether a defined pixel location in a graphics display is within a window in an X Y coordinate system. The respective X and Y coordinates of the selected pixel are separately compared with the window limits. The window limits are preferable expressed as the X and Y coordinates of two diagonally opposite vertexes of a rectangular window. The results of this comparison are preferable available in two forms. In a first embodiment a single data processing instruction enables the generation of a digital data word which indicates the relation of the pixel to the window. This digital word includes a separate indication of the relationship of the pixel to the vertical and horizontal window limits. This indication can be used to generate a "trivial rejection" in determining whether a line or line segment passes through the window by ANDing the results for two points on the line.

Abstract: A graphics data processing apparatus having graphic image operations on two images. Two graphic images are formed into a single combined image based upon a predetermined combination of the multibit color codes representing corresponding pixels of the two images. A transparent color code is permitted for the first of the graphic images. The combination of a transparent color code from the first graphic image with any color code from the second graphic image yields the color code of the second graphic image. This innovation enables the use of color codes having selectable numbers of bits set by the number stored in a pixel size register. In particular the transparent color code, which is detected by a transparent color code detection device independent of the image operation, has a selectable number of bits set by the pixel size register in a manner like any other color code.