Abstract: A palette device controllable by a digital computer with a video memory to produce signals representing color for a video monitor. The palette device includes a multiple-bit input latch for entry of color codes from the video memory, and a look-up table memory for supplying color data words in response to color codes from the input latch. A digital to analog converter responds to color data words to produce an analog color signal. Selection circuitry connected to the input latch and to the look-up table memory supplies the digital to analog converter either with a color data word supplied by the look-up table memory or with a color data word comprised of color codes from the input latch. Improved graphics computer systems, facsimile systems, printer systems and other systems and methods are also disclosed.

Abstract: In a multi-tasking computing system environment, one program is halted and context switched out so that a processor may context switch in a subsequent program for execution. Processor state information exists which reflects the state of the program being context switched out. Storage of this processor state information permits successful resumption of the context switched out program. When the context switched out program is subsequently context switched in, the stored processor information is loaded in preparation for successfully resuming the program at the point in which execution was previously halted. Although, large areas of memory can be allocated to processor state information storage, only a portion of this may need to be preserved across a context switch for successfully saving and resuming the context switched out program.

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: This invention is an iterative technique for division. The divisor has N bits and the numerator has more than N bits, generally 2N bits. Each iteration includes initial detection of the position of a left most one bit (1011, 1035) of N most significant bits of the numerator. If this L is not zero, then the numerator in left shifted by L places (1016, 1039), the next L quotient bits are set to zero and the number of completed iterations of the division is incremented by L. An alternative embodiment detects bit position of the left most one of an exclusive OR of the N most significant bits of the numerator and the divisor. If this is nonzero, then the numerator shifts this number of places and the corresponding quotient bits are set to "0". Next the division technique calculates the difference between the N most significant bits of the numerator and the divisor. If the difference is greater than or equal to zero, then the next quotient bit is "1".

Abstract: An iterative technique for division having a divisor of N bits and a numerator of more than N bits. Each iteration includes initial detection of the position of a left most one bit (1011, 1035) of N most significant bits of the numerator. If this L is not zero, then the numerator is left shifted by L places (1016, 1039), the next L quotient bits are set to zero and the number of completed iterations is incremented by L. An alternative embodiment detects bit position of the left most one of an exclusive OR of the N most significant bits of the numerator and the divisor. Next the divisor is subtracted from the N most significant bits of the numerator. If the difference is greater than or equal to zero, then the next quotient bit is "1" and the difference is substituted for the N most significant bits of the numerator. If the difference is less than zero, then the next quotient bit is "0". Then the numerator is left shifted one place. These iterations repeat until they exceed N.

Abstract: A circuit 83, 97 is provided for selectively interpreting data received in a format selected from the big-endian and little-endian formats to an other one of the big-endian and little-endian formats and includes an array of j sequentially ordered data input terminals for receiving a j-bit word of data formatted in a preselected one of the big-endian and little-endian formats. An array of j sequentially ordered first AND gates 126 is provided, each first AND gate 126 having first and second input ports and an output port, the first input port of the n.sup.th first AND gate 126 coupled to the n.sup.th one of the input terminals, the second input ports of the first AND gates 126 coupled to a control signal. An array of j sequentially ordered second AND gates 128 are provided, and each second AND gate 128 having first and second input ports and an output port, of the first input port of an n.sup.th one of the second AND gates 128 coupled to a (j-n+1).sup.

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: An apparatus and method for filling regions bounded by piecewise-conic curves and more particularly to such an apparatus and method which is directed to curves defined by a conic equation. This simplifies the process of generating filled contours in applications, such as printing, which are based on font outlines while at the same time reducing computer time and generating more accurate results for each curve generation.

Abstract: A color palette selects a master clock from plural clock signals received at clock input terminals in response to a master clock selection control word received at control data terminals. A circuit forms a plurality of divided down clock signals from selected divide ratios of the master clock. A circuit selects a shift clock from among the divided down clock signals in response to at least some bits of an output clock selection control word received at the control data terminals. A circuit selectively enables and disables the shift clock in response to blanking data. A circuit selects a video clock from among the divided down clock signals in response to at least some bits of the output clock selection control word. A circuit synchronizes multiple bit words of color code received at color code input terminals with the master clock. A circuit outputs at least one memory recall address in response to receiving each multiple bit word of color code.

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: 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: An interface for use with a multiprocessor computer system, having a host processor system and a graphics processor system. The interface permits extended functions to be developed on the host system or on another system, and subsequently loaded to the graphics processor system. The interface comprises software residing on both the host system side and the graphics system side, which operates at run time to permit the function to be called from a main program running on the host. The function's arguments are passed to the graphics system so that the function is executed by the graphics processor.

Abstract: A microprocessor, specially adapted for graphics processing applications, and which has a self-emulation capability by which the contents of its internal registers may be dumped or loaded to or from external memory on an instruction-by-instruction basis, is disclosed. The microprocessor has circuitry which is responsive to an emulate enable signal, or to a predetermined instruction code, so that normal execution is halted at the end of the ion, with execution jumping to a predetermined vector. Responsive to a dump signal, the microprocessor begins execution of a routine which presents a predetermined series of memory addresses on a memory bus, in conjunction with the contents of registers internal to the microprocessor. Accordingly, the addressed locations of a memory device connected to the memory bus can be written with the register contents, for subsequent interrogation by the user.

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 graphics coprocessor designed to work in conjunction with a host graphic processor in a graphics system. The coprocessor is adapted to perform arithmetic calculations including matrix calculations. The matrix size is such that the intermediate results require more registers than are practical to include in the coprocessor. This has been solved by arranging for certain selected ones of the intermediate results to continue within the program execution from stage to stage and avoiding intermediate storage.