31.7 LUT-SSM: A 99.3TFLOPS/W LUT-Based State-Space Model Accelerator Using Energy-Efficient Element-Wise Layer Fusion and LUT-Friendly Weight-Only Quantization

State-space models (SSMs) and weight-only quantization alleviate huge external memory access with a minimal accuracy degradation. To support both efficiently, we propose LUTSSM, a LUT-based SSM accelerator with a many-to-many LUT-ACC and an element-wise (EW) layer fusion. LUT-SSM efficiently supports INT-FP GEMM and sequential EW operations in the SSM blocks. Fabricated in 28nm FD-SOI, LUT-SSM achieves 99.3TFLOPS/W peak efficiency and 96.1TFLOPS/W on Mamba 1.4B, improving energy efficiency by$1.28 \times$over recent designs.