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i A PHYSICAL IMPLEMENTATION WITH CUSTOM LOW POWER ...

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The specifications of the hardware fabric are the number of ALUs per stripe and the<br />

number of Computational (ALU) stripes. A 20X18 configuration represents a RHF with 20<br />

ALUs per stripe and 18 ALU stripes. The number of multiplexer stripes is one less than the<br />

number of the ALU stripes, as the ALU and MUX stripes alternate each other. The final ALU<br />

stripe in the design is followed by a special interconnect stripe called the FINALMUX stripe.<br />

The FINALMUX stripe has its inputs from the last ALU stripe and from specialized ALU stripes<br />

called “early exit” ALU stripes. The FINALMUX stripe multiplexes these inputs to the get the<br />

final output of the hardware fabric.<br />

2.2 ARITHMETIC AND LOGIC UNIT (ALU)<br />

The ALU performs conventional arithmetic and logical operations. In addition to the normal<br />

operations, a specialized hardware predication function is implemented within the ALU for<br />

implementing SDFGs [3] [4]. This operation requires a third single-bit operand called<br />

predicator input to be included in the ALU. The predicator input acts as a selector to choose one<br />

of the two operands INP1 and INP2 [3]. Figure 2-2 below shows the logical diagram of the ALU<br />

used in the hardware fabric. The control pins of the ALU select the logical operation performed<br />

by the ALU.<br />

9

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