Achronix Semiconductor Corporation

Tabula, Inc.

Intel Corporation

Agate Logic, Inc.

Leopard Logic Inc.

Daniel J Pugh

Raymond Nijssen

Michael Philip Fitton

Marcel Van Der Goot

Herman Henry Schmit

Andrew Edward Caldwell

Steven L Teig

Jason Rupert Redgrave

Mark Edward Rollins

Dale Wong

Andrew Fox

A tile of an FPGA includes a multiple mode arithmetic circuit. The multiple mode arithmetic circuit is configured by control signals to operate in an integer mode, a floating-point mode, or both. In some example embodiments, multiple integer modes (e.g., unsigned, two's complement, and sign-magnitude) are selectable, multiple floating-point modes (e.g., 16-bit mantissa and 8-bit sign, 8-bit mantissa and 6-bit sign, and 6-bit mantissa and 6-bit sign) are supported, or any suitable combination thereof. The tile may also fuse a memory circuit with the arithmetic circuits. Connections directly between multiple instances of the tile are also available, allowing multiple tiles to be treated as larger memories or arithmetic circuits. By using these connections, referred to as cascade inputs and outputs, the input and output bandwidth of the arithmetic circuit is further increased.

Multiple mode arithmetic circuit

A tile of an FPGA provides memory, arithmetic functions, or both. Connections directly between multiple instances of the tile are available, allowing multiple tiles to be treated as larger memories or arithmetic circuits. By using these connections, referred to as cascade inputs and outputs, the input and output bandwidth of the arithmetic and memory circuits are increased, operand sizes are increased, or both. By using the cascade connections, multiple tiles can be used together as a single, larger tile. Thus, implementations that need memories of different sizes, arithmetic functions operating on different sized operands, or both, can use the same FPGA without additional programming or waste. Using cascade communications, more tiles are used when a large memory is needed and fewer tiles are used when a small memory is needed and the waste is avoided.

Cascade communications between FPGA tiles

A tile of an FPGA fuses memory and arithmetic circuits. Connections directly between multiple instances of the tile are also available, allowing multiple tiles to be treated as larger memories or arithmetic circuits. By using these connections, referred to as cascade inputs and outputs, the input and output bandwidth of the arithmetic circuit is further increased. The arithmetic unit accesses inputs from a combination of: the switch fabric, the memory circuit, a second memory circuit of the tile, and a cascade input. In some example embodiments, the routing of the connections on the tile is based on post-fabrication configuration. In one configuration, all connections are used by the memory circuit, allowing for higher bandwidth in writing or reading the memory. In another configuration, all connections are used by the arithmetic circuit.

Fused memory and arithmetic circuit

In some example embodiments a logical block comprising twelve inputs and two six-input lookup tables (LUTs) is provided, wherein four of the twelve inputs are provided as inputs to both of the six-input lookup tables. This configuration supports efficient field programmable gate array (FPGA) implementation of multipliers. Each six-input LUT comprises two five-input lookup tables (LUT5s) that are used to form Booth encoding multiplier building blocks. The five inputs to each LUT5 are two bits from a multiplier and three Booth-encoded bits from a multiplicand. By assembling building blocks, multipliers of arbitrary size may be formed.

Efficient FPGA multipliers

In some example embodiments a logical block comprising twelve inputs and two six-input lookup tables (LUTs) is provided, wherein four of the twelve inputs are provided as inputs to both of the six-input lookup tables. This configuration supports efficient field programmable gate array (FPGA) implementation of multipliers. Each six-input LUT comprises two five-input lookup tables (LUTs) that are used to form Booth encoding multiplier building blocks. The five inputs to each LUTare two bits from a multiplier and three Booth-encoded bits from a multiplicand. By assembling building blocks, multipliers of arbitrary size may be formed.

Some embodiments provide a reconfigurable IC. This IC includes a set of reconfigurable circuits for performing a mathematical operation in more than one reconfiguration cycle. To perform the mathematical operation when at least one operand has n bits, the reconfigurable circuits performs a first sub-operation on m of n bits in a first reconfiguration cycle, and a second sub-operation on p of n bits in a second reconfiguration cycle. The reconfigurable IC also includes at least one storage element for storing at least a portion of the results of the first sub-operation for use during the second reconfiguration cycle in the second sub-operation.

Performing mathematical and logical operations in multiple sub-cycles

Some embodiments provide a method of providing configurable ICs to a user. The method provides the configurable IC and a set of behavioral descriptions to the user. The behavioral descriptions specify the effects of accesses to a memory by a set of memory ports given a set of parameters chosen by the user.

System and method of providing a memory hierarchy

Some embodiments provide a reconfigurable IC that implements a design that is designed at a particular design clock rate. The reconfigurable IC includes reconfigurable circuits for performing operations on a set of inputs in the particular design. The IC further includes routing circuits for routing signals to and from the logic circuits to allow the logic circuits to perform the operations. The reconfigurable IC implements the design by having reconfigurable circuits that reconfigure at a rate faster than the design clock rate. For at least one operation which is defined at the design clock rate, the reconfigurable IC replicates the operation set in at least two reconfiguration cycles to reduce consumption of routing circuits.

Growing community of inventors

San Jose, CA, United States of America

Daniel J Pugh