摘要:
An arithmetic processor and an addition/subtraction circuit therefor are disclosed. The arithmetic processor comprises a plurality of the addition/subtraction units arranged in parallel, each unit being capable of carrying out addition (or subtraction) with respect to respective digits of two operands. An addition/subtraction unit comprises a first circuit and a second circuit coupled to receive binary signals each representing a respective digit of the operands. At least a first of the two binary signals is a 2-bit signal representing a signed digit expression, one bit of which ("the sign bit") represents the sign of one of the digits of the operands and the other bit of which ("the magnitude bit") represents the magnitude of that one digit of the operands. The first circuit provides a binary signal representing an intermediate carry (or borrow) and the second circuit provides a binary signal representing an intermediate sum (or difference) from the two binary signals representing the digits of the operands. The addition/subtraction unit further comprises a third circuit which is coupled to receive the intermediate sum (or difference) binary signal output from the second circuit and a binary signal representing an intermediate carry (or borrow) from a next-lower-order digit, and outputs a 2-bit binary signal representing an addend (or subtrahend). That 2-bit signal output by the third circuit represents a signed digit expression, one bit, i.e., the sign bit, represents the sign of the addend (or subtrahend) and the other bit, i.e., the magnitude bit, represents the magnitude of the addend (or subtrahend).
摘要:
A high speed arithmetic processor and adder circuitry thereof are disclosed in which carry (borrow) propagation is never more than one digit. Addition (or subtraction) are performed by: (a) determining an intermediate carry (or borrow) at the i-th order position and an intermediate sum (or difference) at the i-th order position from the addend (or subtrahend) and the augend (or minuend) and (b) determining the sum (or difference) of the intermediate sum (or difference) at the i-th order position and the intermediate carry (or borrow) at the (i-1)-th or next-lower-order position. Logic equations, truth tables and circuitry are disclosed for implementing several embodiments of the invention.
摘要:
An arithmetic processor is disclosed for performing arithmetic operations utilizing an arithmetic operand represented by a signed digit expression having a plurality of digits which may have a positive, zero or negative value. The processor comprises: first circuitry coupled to receive a signal related to the most significant digit of a signed digit expression number Y having nonnegative (or nonpositive) digits other than the most significant digit, and for providing in response to a control signal, a signal representing the logical negation or inversion of the sign of the most significant digit; second circuitry coupled to receive at least one signal related to digits other than the most significant digit of the number Y, and for providing in response to a control signal, at least one signal representing the logical negation or inversion of those digits; and third circuitry coupled to receive a signal related to the least significant digit of the number Y, and for providing in response to a control signal, a signal representing the least significant digit plus 1 (or minus 1). The first and second circuitry invert the signs of the digits of the number Y, and the third circuitry adds (or subtracts) 1 from the least significant digit. The processor also includes circuitry coupled to receive the signals provided by the first, second and third circuitry and a signal representing a number X, and providing a signal representing the sum or difference of the numbers X and Y depending on the control signal.
摘要:
A high speed processor including a multiplier is disclosed. The multiplier includes a multiplier recorder circuit which may record multipliers in groups of digits, and intermediate partial product generators which generate partial products from the recorded digits and a multiplicand. Addition/subtraction is then carried out on the intermediate partial products generated by the partial product generators. The processor may operate using signed digit expressions.
摘要:
A high speed arithmetic processor includes an array of arithmetic cells which operate on digits internally represented in a signed-digit binary format. Certain of these cells perform subtraction operations on two ordinary binary digits, and produce the difference in a 2-bit signed-digit binary format, without requiring a separate ordinary binary to signed-digit binary converter.
摘要:
An arithmetic processor cable of performing successive multiplication operations at high speeds is described in which the resultant product, internally represented as a carry-save or signed-digit expression, may be directly input in that form as the multiplier for the next successive multiplication operation. Additionally, a multiplier recoder circuit is provided which recodes the binary multiplier, in the form of a carry-save or signed-digit expression into a radix 4 signed-digit number, in order to further increase the operating speed.
摘要:
A high speed divider circuit which implements a shift/subtract division method utilizing signed-digital binary expressions for the internal operands includes a quotient determining circuit which determines the quotient digit from the partial remainder, and a pluarlity of arithmetic cells which determine successive quotient digits by subtracting the product of the divisor and the sequential digits from the sequential partial remainders. The arithmetic cells which process the two lowest significant digits, the cells which process the most significant digits, the cells which process the intermediate digits and the cells which determine the initial partial remainder are each specifically tailored to perform their respective functions and thereby result in a divider which requires fewer circuit elements, and is simpler to implement in an integrated circuit.
摘要:
A high speed arithmetic processor which may compactly be fabricated on an LSI chip is disclosed. The arithmetic processor in a first-step arithmetic operation determines an intermediate carry (or intermediate borrow) for a higher order arithmetic operation from an internal operand such as augend (or minuend) and an addend (or subtrahend) for each digit in addition (or subtraction) of signed digit numbers, carried out as an internal arithmetic operation, and determines an intermediate sum (or intermediate difference). In a second step arithmetic operation, the processor obtains a final sum (or difference) for each digit from the intermediate sum (or intermediate difference) obtained in the first step arithmetic operation and an intermediate carry (or intermediate borrow) from a lower order arithmetic operation. The sign of an internal operand is either inverted or the internal operand is converted to 0 in accordance with the value of a control signal and then provided as the internal operand for processing in the first step arithmetic operation. Such sign inversion or conversion of the operand to zero enables the first and second step arithmetic operations to be performed utilizing addition and/or subtraction only.
摘要:
A method of making an MOS-type semiconductor device wherein the surface thereon for the conductors is flat. For this purpose, a polycrystalline silicon layer is provided and a part of the layer is selectively oxidized, so that the remaining portion of the layer acts as a lead for connecting a functional region such as a source region, a drain region etc. with the conductor layer. When said oxidization is performed, the diffusion from the polycrystalline silicon layer into the substrate occurs due to heating, so that said functional regions are formed at the same time.
摘要:
In a C MOS IC as shown in FIG. 7(A) and FIG. 8, the IC comprises vertical row of horizontally long blocks, each block comprising p-type MOS transistor region and n-type MOS transistor region, the IC comprises horizontal wirings of aluminum (31, 32, 33) and vertical wirings of polycrystalline silicon (61, 62, 63, 64, 65, 41, 42), with insulation films on the upper side and on the lower side of the polycrystalline silicon film, between the rows (I, II, . . .), said horizontal aluminum wirings (31, 32, 33) and said polycrystalline silicon wiring (61, 62 . . ., 41, 42) being appropriately connected through openings (105, 105 . . .) formed in said insulation film inbetween, said vertical polycrystalline silicon wirings being connected through aluminum wirings in said blocks.