Hybridthreads Compiler: C to VHDL Jim Stevens (jstevens@ittc.ku) and Fabrice Baijot (bricefab@ittc.ku)

1. HTC 1.0 Synthesis Results Hybridthreads Compiler: C to VHDLJim Stevens (jstevens@ittc.ku.edu) and Fabrice Baijot (bricefab@ittc.ku.edu) Background Approach • Hthreads OS eliminates the HW/SW boundary for CPU/FPGA applications • Threads in both software and hardware • OS services available to hardware threads • Creating hardware threads in VHDL still difficult for software engineers • Need a compiler that can translate unaltered C threads into VHDL • Allow for fast design space exploration • Enable software engineers to create custom hardware • Leverage existing GCC front end with custom VHDL back end • HIFGEN extension to GCC translates GIMPLE into new Hardware Intermediate Form (HIF) language • Back end is a compiler for HIF called HIF2VHDL Design Flow Implementation Status • HIFGEN • Walks GIMPLE tree to generate equivalent HIF • Runs after GCC’s GIMPLE optimizers (many free optimizations) • HIF2VHDL • Parses and type checks the HIF code • Elaborates HIF into a low level CFG language • Clean up optimizations • Generates VHDL code that implements the hardware thread with a finite state machine • HTC 1.0 (completed summer 2006) • 32-bit primitive types/operations (ints and pointers) • Aggregate types/operations (arrays and structs) • Demonstrates function call model in hardware threads • HTC 2.0 (currently in development) • Complete support for ANSI C language • Framework for future research in high-level language to hardware compilation and FPGA programming models