1
0
rocket-chip/rocket
2014-09-02 14:34:36 -07:00
..
src/main/scala rename Unsigned.size to Unsigned.clog2 2014-06-14 13:58:07 -07:00
.gitignore add .gitignore 2014-08-18 19:27:50 -07:00
build.sbt add README and sbt files 2014-08-18 19:23:10 -07:00
chisel-dependent.sbt fixes sbt error during first run 2014-09-02 14:34:36 -07:00
hardfloat-dependent.sbt add README and sbt files 2014-08-18 19:23:10 -07:00
README.md rename refs to zynq-fpga to fpga-zynq 2014-08-29 10:26:48 -07:00
uncore-dependent.sbt add README and sbt files 2014-08-18 19:23:10 -07:00

Rocket Core Generator

Rocket is a 6-stage single-issue in-order pipeline that executes the 64-bit scalar RISC-V ISA. Rocket implements an MMU that supports page-based virtual memory and is able to boot modern operating systems such as Linux. Rocket also has an optional IEEE 754-2008-compliant FPU, which implements both single- and double-precision floating-point operations, including fused multiply-add.

We plan to open-source our Rocket core generator written in Chisel in the near future. We are currently in the process of cleaning up the repository. Please stay tuned.

Currently, a Rocket core with an 8 KB direct-mapped L1 instruction cache and an 8 KB direct-mapped L1 data cache has been instantiated and committed to the fpga-zynq infrastructure repository. A copy of the generated Verilog is available here.

The following table compares a 32-bit ARM Cortex-A5 core to a 64-bit RISC-V Rocket core built in the same TSMC process (40GPLUS). Fourth column is the ratio of RISC-V Rocket to ARM Cortex-A5. Both use single-instruction-issue, in-order pipelines, yet the RISC-V core is faster, smaller, and uses less power.

ISA/Implementation ARM Cortex-A5 RISC-V Rocket R/A
ISA Register Width 32 bits 64 bits 2
Frequency >1 GHz >1 GHz 1
Dhrystone Performance 1.57 DMIPS/MHz 1.72 DMIPS/MHz 1.1
Area excluding caches 0.27 mm2 0.14 mm2 0.5
Area with 16KB caches 0.53 mm2 0.39 mm2 0.7
Area Efficiency 2.96 DMIPS/MHz/mm2 4.41 DMIPS/MHz/mm2 1.5
Dynamic Power <0.08 mW/MHz 0.034 mW/MHz >= 0.4