Ip-first, LLC

International Business Machines Corporation

Via Technologies, Inc.

Motorola Corporation

Jp First LLC

Timothy A Elliott

G Glenn Henry

Christopher Hans Olson

Terry J Parks

Terence M Potter

Robert Thaddeus Golla

Rodney E Hooker

Gerard M Col

Robert T Golla

Lee Evan Eisen

John Stephen Muhich

David James Shippy

Thomas A Crispin

Bradley Gene Burgess

Michael Putrino

Albert J Loper, Jr

Albert John Loper

Frank J Palermo

GGlenn Henry

An apparatus having operand registers, an opcode detector, a carryless preformat unit, a compressor, a left shifter, and exclusive-OR logic. The operand registers receive operands for a carryless multiplication. The opcode detector receives a carryless multiplication instruction, and asserts a carryless signal. The carryless preformat unit partitions a first operand into a plurality of parts that are such that a Booth encoder is precluded from selection of second partial products of a second operand, where the second partial products reflect implicit carry operations. The compressor sums first partial products of the second operand via carry save adders arranged in a Wallace tree configuration, where generation of carry bits is disabled. The left shifter shifts one or more outputs of the compressor. The exclusive-OR logic executes an exclusive-OR function to yield a carryless multiplication result.

Mechanism for carryless multiplication that employs booth encoding

An apparatus having a carryless preformat unit, a Booth encoder, a compressor, a left shifter, and exclusive-OR logic. The carryless preformat unit receives a multiplier operand and partitions the multiplier operand into parts. The Booth encoder receives the parts and directs selection of first partial products of a multiplicand that do not reflect implicit carry operations. The compressor sums the first partial products via a configuration of carry save adders that generate sum bits and carry bits, where generation of the carry bits is disabled during execution of the carryless multiplication. The left shifter shifts bits of one or more outputs of the compressor. The exclusive-OR logic is coupled to the compressor and the left shifter, and is configured to execute an exclusive-OR function on the outputs to yield a carryless multiplication result.

Carryless multiplication unit

An apparatus is provided for performing carryless multiplication. The apparatus has an opcode dectector and a carryless preformat unit. The opcode dectector is configured to receive a carryless multiplication instruction, and is configured to assert a carryless signal responsive to receipt of the carryless multiplication instruction. The carryless preformat unit is configured to partition the first operand into parts responsive to assertion of the carryless signal, where the parts are configured such that a Booth encoder selects first partial products corresponding to a second operand and is precluded from selection of second partial products corresponding to the second operand, and where the second partial products are results of implicit carry operations. The first partial products are exclusive-ORed together to yield a carryless multiplication result.

Carryless multiplication preformatting apparatus and method

A microprocessor includes a plurality of execution units configured to receive instructions and operands thereof and to execute the instructions. An instruction scheduler issues the instructions to the execution units and selects sources of the instruction operands. At least one of the execution units detects one of the operands of one of the instructions is a denormal operand, generates an indication that the instruction needs to be replayed in response to detecting the denormal operand, and provides the denormal operand to the instruction scheduler in response to detecting the denormal operand, rather than normalizing the denormal operand. The instruction scheduler normalizes the denormal operand, in response to the indication, and causes the normalized operand, rather than the denormal operand, to be provided to the execution unit when the instruction is replayed.

Apparatus and method for detection and correction of denormal speculative floating point operand

An x87 fused multiply-add (FMA) instruction in the instruction set of an x86 architecture microprocessor is disclosed. The FMA instruction implicitly specifies the two factor operands as the top two operands of the x87 FPU register stack and explicitly specifies the third addend operand as a third x87 FPU register stack register. The microprocessor multiplies the first two operands and adds the product to the third operand to generate a result. The result is stored into the third register and the first two operands are popped off the stack. In an alternate embodiment, the third operand is also implicitly specified as being stored in the register that is two registers below the top of stack register; the result is also stored therein. The instruction opcode value is in the x87 opcode range.

X87 fused multiply-add instruction

An apparatus and method for performing cryptographic operations. In one embodiment, an apparatus is provided for performing cryptographic operations. The apparatus includes fetch logic, keygen logic, and execution logic. The fetch logic is disposed within a microprocessor and receives cryptographic instruction single atomic cryptographic instruction as part of an instruction flow executing on the microprocessor. The cryptographic instruction single atomic cryptographic instruction prescribes one of the cryptographic operations, and also prescribes that a provided cryptographic key be expanded into a corresponding key schedule for employment during execution of the one of the cryptographic operations. The keygen logic is disposed within the microprocessor and is operatively coupled to the single atomic cryptographic instruction. The keygen logic directs the microprocessor to expand the provided cryptographic key into the corresponding key schedule. The execution logic is coupled to the keygen logic. The execution logic is disposed within the microprocessor and expands the provided cryptographic key into the corresponding key schedule.

Apparatus and method for generating a cryptographic key schedule in a microprocessor

A mechanism for, and method of, clipping a red-green-blue (RGB) integer value to an n-bit maximum value and a processor incorporating the mechanism or the method. In one embodiment, the mechanism includes: (1) a multiplexer having a first input that accepts n low-order bits of the RGB integer value and a select input that accepts at least one high-order bit of the RGB integer value and (2) an n-bit maximum value generator, coupled to a second input of the multiplexer, that provides the n-bit maximum value to the second input, an output of the multiplexer providing the n low-order bits when the at least one high order bit has a zero value and providing the n-bit maximum value when the at least one high order bit has a nonzero value.

Mechanism for clipping RGB value during integer transfer

An apparatus and method for bi-directional format conversion and transfer of data between integer and floating point registers is provided. A floating point register is configured to store floating point data, and integer data, in a variety of numerical formats. Data is moved in and out of the floating point register as integer data, and is converted into floating point format as needed. Separate processor instructions are provided for format conversion and data transfer to allow conversion and transfer operations to be separated.

Instruction set for bi-directional conversion and transfer of integer and floating point data

An apparatus and method are provided for concurrently loading single-precision operands into registers in a microprocessor floating point register file. The apparatus includes translation logic, data logic, and write back logic. The translation logic receives a load macro instruction prescribing an address, and decodes the load macro instruction into a double load micro instruction. The double load micro instruction directs the microprocessor to retrieve the two single-precision operands from the address and to load the two single-precision operands into the two floating point registers. The data logic, coupled to the translation logic, executes the double load micro instruction and retrieves the two single-precision operands from the address. The write back logic, coupled to the data logic, loads the two single-precision operands into the two floating point registers during a single write cycle.

Method and apparatus for double operand load

An apparatus and method for performing single precision multiplication in a microprocessor are provided. The apparatus includes translation logic and extended precision floating point execution logic. The translation logic decodes a single precision multiply instruction into an associated micro instruction sequence directing the microprocessor to fetch a single precision operand from memory and convert it to extended precision format. In addition, the associated micro instruction sequence directs floating point execution logic employing a dual pass multiplication unit to skip a pass associated with computing an insignificant partial product. This insignificant partial product would otherwise result from multiplication of a multiplicand by zeros which are appended to the significand of the fetched operand when it is converted to extended precision format.

Apparatus and method for single precision multiplication

An apparatus and method for calculating a square root of an operand in a microprocessor are provided. The microprocessor has a plurality of square root instructions, each of which specifies a square root calculation precision. The apparatus includes translation logic and execution logic. The translation logic decodes the square root macro instruction into a plurality of prescribed-precision machine instructions according to the square root calculation precision specified by the plurality of square root instructions. The execution logic, coupled to the translation logic, receives the plurality of prescribed-precision machine instructions and calculates the square root of the operand according to the specified square root calculation precision. At least one of the plurality of square root instructions specifies the square root calculation precision such that less significant bits are calculated in the square root than are provided in the operand.

Apparatus and method for fast square root calculation within a microprocessor

An apparatus and method for performing a floating point multiply (by a fixed graphics constant), and converting the product of the multiply into an integer, within a single operation is provided. The apparatus includes detection logic to determine whether a special multiply/convert operation is specified, and if so, floating point conversion logic to adjust a bias constant prior to conversion of the floating point number to an integer. More specifically, if the multiply/convert operation specified relates to calculation of graphic points for display, execution of the multiply convert operation effectively multiplies a specified floating point number by a graphics constant, as part of subtracting the exponent bias.

Mechanism for floating point to integer conversion with RGB bias multiply

A microprocessor is provided for executing a floating point exchange micro instruction sequence to swap the contents a first location and a second location. The microprocessor includes register/control logic that receives a floating point micro instruction, determines that the contents of the first location depend upon resolution of a preceding floating point micro instruction, and provides a signal indicating the dependency. The microprocessor also has interlock logic that, in the event of a dependency forwards a new target location to the preceding floating point micro instruction. The microprocessor also includes target location modification logic that receives the new target location and for provides the new target location to the preceding floating point micro instruction. Modification of the target location allows the floating point exchange micro instruction sequence to execute without resolution delay.

Growing community of inventors

Austin, TX, United States of America

Timothy A Elliott