Macah: A "C-Level" Language for Programming Kernels on Coprocessor Accelerators

Coprocessor accelerator architectures like FPGAs and GPUs are increasingly used in embedded systems because of their high performance on computation-heavy inner loops of a variety of applications. However, current languages and compilers for these architectures make it challenging to efficiently implement kernels that have complex, input-dependent control flow and data access patterns. In this paper we argue that providing language support for such kernels significantly broadens the applicability of accelerator architectures. We then describe a new language‐called Macah‐and compiler that provide this support. Macah is a “C-level” language, in the sense that it forces programmers to think about some of the abstract architectural characteristics that make accelerators different from conventional processors. However, the compiler still fills in several important architecture-specific details, so that programming in Macah is substantially easier than using hardware description languages or coprocessor-specific assembly languages. We have implemented a prototype Macah compiler that produces simulatable Verilog which represents the input program mapped onto a model of an accelerator. Among other applications, we have programmed a complex kernel taken from video compression in Macah and have it running in simulation.