"Entire Market Value: When a patentee proves that the patent related feature serves as the predominant basis for customer demand, courts allow damages to be based upon the "entire market value" of the product (i.e., 8% of the sales revenue of Microsoft Office) rather than focusing on the incremental value of the innovation. Here, the Federal Circuit held that the "only reasonable conclusion" is that the date-picker function is not a substantial driver of Office sales. "There was no evidence that anybody anywhere at any time ever bought Outlook . . . because it had a date picker."

Now our patent

SUMMARY OF THE INVENTION

Accordingly, it is an object of this invention to provide a microprocessor with a reduced pin count and cost compared to conventional microprocessors.

It is another object of the invention to provide a high performance microprocessor that can be directly connected to DRAMs without sacrificing microprocessor speed.

It is a further object of the invention to provide a high performance microprocessor in which DMA does not require use of the main CPU during DMA requests and responses and which provides very rapid DMA response with predictable response times.

The attainment of these and related objects may be achieved through use of the novel high performance, low cost microprocessor herein disclosed. In accordance with one aspect of the invention, a microprocessor system in accordance with this invention has a central processing unit, a dynamic random access memory and a bus connecting the central processing unit to the dynamic random access memory. There is a multiplexing means on the bus between the central processing unit and the dynamic random access memory. The multiplexing means is connected and configured to provide row addresses, column addresses and data on the bus.

In accordance with another aspect of the invention, the microprocessor system has a means connected to the bus for fetching instructions for the central processing unit on the bus. The means for fetching instructions is configured to fetch multiple sequential instructions in a single memory cycle. In a variation of this aspect of the invention, a programmable read only memory containing instructions for the central processing unit is connected to the bus. The means for fetching instructions includes means for assembling a plurality of instructions from the programmable read only memory and storing the plurality of instructions in the dynamic random access memory.

In another aspect of the invention, the microprocessor system includes a central processing unit, a direct memory access processing unit and a memory connected by a bus. The direct memory access processing unit includes means for fetching instructions for the central processing unit and for fetching instructions for the direct memory access processing unit on the bus.

In a further aspect of the invention, the microprocessor system, including the memory, is contained in an integrated circuit. The memory is a dynamic random access memory, and the means for fetching multiple instructions includes a column latch for receiving the multiple instructions.

In still another aspect of the invention, the microprocessor system additionally includes an instruction register for the multiple instructions connected to the means for fetching instructions. A means is connected to the instruction register for supplying the multiple instructions in succession from the instruction register. A counter is connected to control the means for supplying the multiple instructions to supply the multiple instructions in succession. A means for decoding the multiple instructions is connected to receive the multiple instructions in succession from the means for supplying the multiple instructions. The counter is connected to said means for decoding to receive incrementing and reset control signals from the means for decoding. The means for decoding is configured to supply the reset control signal to the counter and to supply a control signal to the means for fetching instructions in response to a SKIP instruction in the multiple instructions. In a modification of this aspect of the invention, the microprocessor system additionally has a loop counter connected to receive a decrement control signal from the means for decoding. The means for decoding is configured to supply the reset control signal to the counter and the decrement control signal to the loop counter in response to a MICROLOOP instruction in the multiple instructions. In a further modification to this aspect of the invention, the means for decoding is configured to control the counter in response to an instruction utilizing a variable width operand. A means is connected to the counter to select the variable width operand in response to the counter.

In a still further aspect of the invention, the microprocessor system includes an arithmetic logic unit. A first push down stack is connected to the arithmetic logic unit. The first push down stack includes means for storing a top item connected to a first input of the arithmetic logic unit and means for storing a next item connected to a second input of the arithmetic logic unit. The arithmetic logic unit has an output connected to the means for storing a top item. The means for storing a top item is connected to provide an input to a register file. The register file desirably is a second push down stack, and the means for storing a top item and the register file are bidirectionally connected.

In another aspect of the invention, a data processing system has a microprocessor including a sensing circuit and a driver circuit, a memory, and an output enable line connected between the memory, the sensing circuit and the driver circuit. The sensing circuit is configured to provide a ready signal when the output enable line reaches a predetermined electrical level, such as a voltage. The microprocessor is configured so that the driver circuit provides an enabling signal on the output enable line responsive to the ready signal.

In a further aspect of the invention, the microprocessor system has a ring counter variable speed system clock connected to the central processing unit. The central processing unit and the ring counter variable speed system clock are provided in a single integrated circuit. An input/output interface is connected to exchange coupling control signals, addresses and data with the input/output interface. A second clock independent of the ring counter variable speed system clock is connected to the input/output interface.

In yet another aspect of the invention, a push down stack is connected to the arithmetic logic unit. The push down stack includes means for storing a top item connected to a first input of the arithmetic logic unit and means for storing a next item connected to a second input of the arithmetic logic unit. The arithmetic logic unit has an output connected to the means for storing a top item. The push down stack has a first plurality of stack elements configured as latches and a second plurality of stack elements configured as a random access memory. The first and second plurality of stack elements and the central processing unit are provided in a single integrated circuit. A third plurality of stack elements is configured as a random access memory external to the single integrated circuit. In this aspect of the invention, desirably a first pointer is connected to the first plurality of stack elements, a second pointer connected to the second plurality of stack elements, and a third pointer is connected to the third plurality of stack elements. The central processing unit is connected to pop items from the first plurality of stack elements. The first stack pointer is connected to the second stack pointer to pop a first plurality of items from the second plurality of stack elements when the first plurality of stack elements are empty from successive pop operations by the central processing unit. The second stack pointer is connected to the third stack pointer to pop a second plurality of items from the third plurality of stack elements when the second plurality of stack elements are empty from successive pop operations by the central processing unit.

In another aspect of the invention, a first register is connected to supply a first input to the arithmetic logic unit. A first shifter is connected between an output of the arithmetic logic unit and the first register. A second register is connected to receive a starting polynomial value. An output of the second register is connected to a second shifter. A least significant bit of the second register is connected to The arithmetic logic unit. A third register is connected to supply feedback terms of a polynomial to the arithmetic logic unit. A down counter, for counting down a number corresponding to digits of a polynomial to be generated, is connected to the arithmetic logic unit. The arithmetic logic unit is responsive to a polynomial instruction to carry out an exclusive OR of the contents of the first register with the contents of the third register if the least significant bit of the second register is a "ONE" and to pass the contents of the first register unaltered if the least significant bit of the second register is a "ZERO", until the down counter completes a count. The polynomial to be generated results in said first register.

In still another aspect of the invention, a result register is connected to supply a first input to the arithmetic logic unit. A first, left shifting shifter is connected between an output of the arithmetic logic unit and the result register. A multiplier register is connected to receive a multiplier in bit reversed form. An output of the multiplier register is connected to a second, right shifting shifter. A least significant bit of the multiplier register is connected to the arithmetic logic unit. A third register is connected to supply a multiplicand to said arithmetic logic unit. A down counter, for counting down a number corresponding to one less than the number of digits of the multiplier, is connected to the arithmetic logic unit. The arithmetic logic unit is responsive to a multiply instruction to add the contents of the result register with the contents of the third register, when the least significant bit of the multiplier register is a "ONE" and to pass the contents of the result register unaltered, until the down counter completes a count. The product results in the result register.

The attainment of the foregoing and related objects, advantages and features of the invention should be more readily apparent to those skilled in the art, after review of the following more detailed description of the invention, taken together with the drawings, in which:
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This is why we having been fighting for years, and years