Approximate Multiplier by HEAM

What's HEAM?

• HEAM is a general optimization method to generate high-efficiency approximate multipliers for specific applications.
• This project contains an 8x8 unsigned approximate multiplier based on HEAM for Deep Neural Network (DNN) accelerators and the corresponding Design Compiler(DC) script. Besides, the exact WallaceTree multiplier is included for comparison.

Optimization Procedure of the 8×8 Unsigned Approximate Multiplier

How to compile them?

Make sure that you have installed Design Compiler(DC) and prepared your library files.

compile approximate_multiplier.v

• step 1: set TOP_LEVEL, all_src, and TOP in scripts/top.tcl at line 1, line 11, and line 15 respectively:

set TOP_LEVEL approximate_multiplier
set all_src "approximate_multiplier.v"
set TOP approximate_multiplier

• step 2: run commands in terminal:

dc_shell
source scripts/top.tcl

compile wallacetree.v

• step 1: set TOP_LEVEL, all_src, and TOP in scripts/top.tcl at line 1, line 11, and line 15 respectively:

set TOP_LEVEL wallacetree
set all_src "wallacetree.v"
set TOP wallacetree

• step 2: run commands in terminal:

dc_shell
source scripts/top.tcl

Experiments of the Approximate Multiplier and the Exact WallaceTree multiplier on Design Compiler(DC) in 3Ghz with a 7-nm Predictive Process Design Kit (PDK) Called the ASAP7 PDK[1]

	Ours	WallaceTree	Reduction
Area ( μm * μm )	17.52516	42.98184	59.23%
Power ( μW )	76.2003	151.9432	49.85%

Future

1. add several reproduced approximate multipliers for comparison;
2. add DNNs accelerators results.

Reference

[1] Clark, Lawrence T., et al. "ASAP7: A 7-nm finFET predictive process design kit." Microelectronics Journal 53 (2016): 105-115.