Interleaving behavioral and cycle-accurate descriptions for reconfigurable hardware compilation

This paper describes Haydn, a hardware compilation approach which aims to combine the benefits of cycle accurate descriptions such as ease of control and performance, and the rapid development and design exploration facilities in behavioral synthesis tools. Our approach supports two main features: deriving architectures that meet performance goals involving metrics such as resource usage and execution time, and inferring design behavior by generating behavioral code that is easy to verify and modify from scheduled designs such as pipeline architectures. We report four recent developments that significantly enhance the Haydn approach: (a) a design methodology that supports both cycle-accurate and behavioral levels, in which developers can move from one level to the other: (b) an extended scheduling algorithm which supports operation chaining, pipelined resources (with different latencies and initiation intervals), forwarding technique for loop-carried dependencies, and resource sharing and control; (c) a hardware design flow that can be customized with a script language and extended simulation capabilities for the RC2000 board; and (d) an evaluation of our approach using various case studies, including 3D free-form deformation (FFD), Gouraud shading, Fibonacci series, Montgomery multiplication, and one-dimensional DCT. For instance, our approach has been used to produce various FFD designs in hardware automatically; the smallest at 137 MHz is 294 times faster than software on a dual AMD MP2600+ processor machine at 2.1 GHz, and is 2.7 times smaller and 10% slower than the fastest design at 153 MHz.