As transistors have scaled to nanometer technology, maintaining acceptable power and energy consumption has become more challenging over the years. Approximate computing is a new topic that has been explored as a solution to address these challenges, as some applications may tolerate inaccurate outcome results. We present ApproxRISC, an infrastructure aims for rapid investigation of approximate computing in RISCV processors. Along with software changes, we propose an ISA extension for basic arithmetic operations for approximate computing. ApproxRISCV extends the original RISC-V Foundation infrastructure adding support for approximate computing capabilities in the LLVM compiler, GNU binutils and Spike ISA simulator. Moreover, we propose easy-to-use timing and energy modeling capabilities to the Spike ISA simulator, allowing that applications’ execution time and energy consumption be obtained.