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[![NEORV32](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/figures/neorv32_logo.png)](https://github.com/stnolting/neorv32)
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# The NEORV32 RISC-V Processor
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[![Processor Check](https://github.com/stnolting/neorv32/workflows/Processor%20Check/badge.svg)](https://github.com/stnolting/neorv32/actions?query=workflow%3A%22Processor+Check%22)
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[![RISC-V Compliance](https://github.com/stnolting/neorv32/workflows/RISC-V%20Compliance/badge.svg)](https://github.com/stnolting/neorv32/actions?query=workflow%3A%22RISC-V+Compliance%22)
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[![license](https://img.shields.io/github/license/stnolting/neorv32)](https://github.com/stnolting/neorv32/blob/master/LICENSE)
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[![release](https://img.shields.io/github/v/release/stnolting/neorv32)](https://github.com/stnolting/neorv32/releases)
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* [Overview](#Overview)
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* [Project Status](#Status)
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* [Features](#Features)
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* [FPGA Implementation Results](#FPGA-Implementation-Results)
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* [Performance](#Performance)
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* [Top Entities](#Top-Entities)
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* [**Getting Started**](#Getting-Started)
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* [Contribute/Feedback/Questions](#ContributeFeedbackQuestions)
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* [Legal](#Legal)
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## Overview
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The NEORV32 Processor is a customizable microcontroller-like system on chip (SoC) that is based
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on the RISC-V-compliant NEORV32 CPU. The processor is intended as *ready-to-go* auxiliary processor within a larger SoC
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designs or as stand-alone custom microcontroller.
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The project’s change log is available in the [CHANGELOG.md](https://github.com/stnolting/neorv32/blob/master/CHANGELOG.md) file in the root directory of this repository.
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To see the changes between releases visit the project's [release page](https://github.com/stnolting/neorv32/releases).
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The documentation of the software framework is available online on [GitHub-pages](https://stnolting.github.io/neorv32/files.html).
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For more detailed information take a look at the [:page_facing_up: NEORV32 data sheet](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/NEORV32.pdf) (pdf).
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### Key Features
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* RISC-V-[compliant](#Status) 32-bit `rv32i` [**NEORV32 CPU**](#NEORV32-CPU-Features), compliant to
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* Subset of the *Unprivileged ISA Specification* [(Version 2.2)](https://github.com/stnolting/neorv32/blob/master/docs/riscv-privileged.pdf)
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* Subset of the *Privileged Architecture Specification* [(Version 1.12-draft)](https://github.com/stnolting/neorv32/blob/master/docs/riscv-spec.pdf)
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* Configurable RISC-V-compliant CPU extensions
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* `A` - atomic memory access instructions (optional)
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* `B` - Bit manipulation instructions (optional)
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* `C` - compressed instructions (16-bit) (optional)
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* `E` - embedded CPU (reduced register file (optional)
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* `I` - base integer instruction set (always enabled)
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* `M` - integer multiplication and division hardware (optional)
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* `U` - less-privileged *user mode* (optional)
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* `X` - NEORV32_specific extensions (always enabled)
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* `Zicsr` - control and status register access instructions (+ exception/irq system) (optional)
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* `Zifencei` - instruction stream synchronization (optional)
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* `PMP` - physical memory protection (optional)
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* `HPM` - hardware performance monitors (optional)
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* Full-scale RISC-V microcontroller system / **SoC** [**NEORV32 Processor**](#NEORV32-Processor-Features) with optional submodules
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* optional embedded memories (instructions/data/bootloader, RAM/ROM) and caches
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* timers (watch dog, RISC-V-compliant machine timer)
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* serial interfaces (SPI, TWI, UART) and general purpose IO
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* external bus interface (Wishbone / [AXI4](#AXI4-Connectivity))
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* [more ...](#NEORV32-Processor-Features)
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* Software framework
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* core libraries for high-level usage of the provided functions and peripherals
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* application compilation based on [GNU makefiles](https://github.com/stnolting/neorv32/blob/master/sw/example/blink_led/makefile)
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* GCC-based toolchain ([pre-compiled toolchains available](https://github.com/stnolting/riscv_gcc_prebuilt))
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* bootloader with UART interface console
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* runtime environment
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* several example programs
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* [doxygen-based](https://github.com/stnolting/neorv32/blob/master/docs/doxygen_makefile_sw) documentation: available on [GitHub pages](https://stnolting.github.io/neorv32/files.html)
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* [FreeRTOS port](https://github.com/stnolting/neorv32/blob/master/sw/example/demo_freeRTOS) available
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* [**Full-blown data sheet**](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/NEORV32.pdf) (pdf)
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* Completely described in behavioral, platform-independent VHDL - no primitives, macros, etc.
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* Fully synchronous design, no latches, no gated clocks
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* Small hardware footprint and high operating frequency
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### Design Principles
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* From zero to *hello_world*: Completely open source and documented.
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* Plain VHDL without technology-specific parts like attributes, macros or primitives.
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* Easy to use – working out of the box.
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* Clean synchronous design, no wacky combinatorial interfaces.
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* Be as small as possible – but with a reasonable size-performance tradeoff.
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* Be as RISC-V-compliant as possible.
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* The processor has to fit in a Lattice iCE40 UltraPlus 5k low-power FPGA running at 20+ MHz.
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### Status
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The processor is [synthesizable](#FPGA-Implementation-Results) (tested on *real hardware* using Intel Quartus Prime, Xilinx Vivado and Lattice Radiant/Synplify Pro) and can successfully execute
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all the [provided example programs](https://github.com/stnolting/neorv32/tree/master/sw/example) including the [CoreMark benchmark](#CoreMark-Benchmark).
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The processor passes the official `rv32_m/C`, `rv32_m/I`, `rv32_m/M`, `rv32_m/privilege` and `rv32_m/Zifencei`
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[RISC-V compliance tests (new framework v2)](https://github.com/riscv/riscv-compliance).
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| Project component | CI status |
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|:----------------- |:----------|
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| [NEORV32 processor](https://github.com/stnolting/neorv32) | [![Processor Check](https://github.com/stnolting/neorv32/workflows/Processor%20Check/badge.svg)](https://github.com/stnolting/neorv32/actions?query=workflow%3A%22Processor+Check%22) |
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| [SW Framework Documentation (online)](https://stnolting.github.io/neorv32/files.html) | [![Doc@GitHub-pages](https://github.com/stnolting/neorv32/workflows/Deploy%20SW%20Framework%20Documentation%20to%20GitHub-Pages/badge.svg)](https://stnolting.github.io/neorv32/files.html) |
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| [Pre-built toolchains](https://github.com/stnolting/riscv_gcc_prebuilt) | [![Test Toolchains](https://github.com/stnolting/riscv_gcc_prebuilt/workflows/Test%20Toolchains/badge.svg)](https://github.com/stnolting/riscv_gcc_prebuilt/actions?query=workflow%3A%22Test+Toolchains%22) |
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| [RISC-V compliance test](https://github.com/stnolting/neorv32/blob/master/riscv-compliance/README.md) | [![RISC-V Compliance](https://github.com/stnolting/neorv32/workflows/RISC-V%20Compliance/badge.svg)](https://github.com/stnolting/neorv32/actions?query=workflow%3A%22RISC-V+Compliance%22) |
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### To-Do / Wish List / Help Wanted
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* Use LaTeX for data sheet
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* Further size and performance optimization
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* Further expand associativity configuration of instruction cache (4x/8x set-associativity)
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* Add data cache
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* Burst mode for the external memory/bus interface
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* RISC-V `F` (using [`Zfinx`](https://github.com/riscv/riscv-zfinx/blob/master/Zfinx_spec.adoc)?) CPU extension (single-precision floating point)
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* Add template (HW module + intrinsics skeleton) for custom instructions?
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* Implement further RISC-V (or custom?) CPU extensions
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* More support for FreeRTOS (like *all* traps)
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* Port additional RTOSs (like [Zephyr](https://github.com/zephyrproject-rtos/zephyr) or [RIOT](https://www.riot-os.org))
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* Maybe port [CircuitPython](https://circuitpython.org/) (just for fun)
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* Add debugger ([RISC-V debug spec](https://github.com/riscv/riscv-debug-spec))
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* ...
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* [Ideas?](#ContributeFeedbackQuestions)
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## Features
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The full-blown data sheet of the NEORV32 Processor and CPU is available as pdf file:
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[:page_facing_up: NEORV32 data sheet](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/NEORV32.pdf).
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### NEORV32 Processor Features
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![neorv32 Overview](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/figures/neorv32_processor.png)
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The NEORV32 Processor provides a full-scale microcontroller-like SoC based on the NEORV32 CPU. The setup
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is highly customizable via the processor's top generics and already provides the following *optional* modules:
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* processor-internal data and instruction memories (**DMEM** / **IMEM**) & cache (**iCACHE**)
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* bootloader (**BOOTLDROM**) with UART console and automatic application boot from SPI flash option
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* machine system timer (**MTIME**), RISC-V-compliant
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* watchdog timer (**WDT**)
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* universal asynchronous receiver and transmitter (**UART**) with simulation output option via text.io
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* 8/16/24/32-bit serial peripheral interface controller (**SPI**) with 8 dedicated chip select lines
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* two wire serial interface controller (**TWI**), with optional clock-stretching, compatible to the I²C standard
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* general purpose parallel IO port (**GPIO**), 32xOut & 32xIn, with pin-change interrupt
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* 32-bit external bus interface, Wishbone b4 compliant (**WISHBONE**), *standard* or *pipelined* handshake/transactions mode
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* wrapper for **AXI4-Lite Master Interface** (see [AXI Connectivity](#AXI4-Connectivity))
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* PWM controller with 4 channels and 8-bit duty cycle resolution (**PWM**)
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* GARO-based true random number generator (**TRNG**)
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* custom functions units (**CFU0** and **CFU1**) for tightly-coupled custom co-processors
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* system configuration information memory to check hardware configuration by software (**SYSINFO**, mandatory - not *optional*)
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### NEORV32 CPU Features
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The NEORV32 CPU is **compliant** to the
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[official RISC-V specifications (2.2)](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/riscv-spec.pdf) including a subset of the
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[RISC-V privileged architecture specifications (1.12-draft)](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/riscv-spec.pdf)
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tested via the [official RISC-V Compliance Test Framework](https://github.com/riscv/riscv-compliance)
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(see [`riscv-compliance/README`](https://github.com/stnolting/neorv32/blob/master/riscv-compliance/README.md)).
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More information regarding the CPU including a detailed list of the instruction set and the available CSRs can be found in
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the [:page_facing_up: NEORV32 data sheet](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/NEORV32.pdf).
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**General**:
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* Modified Harvard architecture (separate CPU interfaces for data and instructions; NEORV32 processor: Single processor-internal bus via I/D mux)
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* Two stages in-order pipeline (FETCH, EXECUTE); each stage uses a multi-cycle processing scheme
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* No hardware support of unaligned accesses - they will trigger an exception
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* BIG-ENDIAN byte-order, processor's external memory interface allows endianness configuration to connect to system with different endianness
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* All reserved or unimplemented instructions will raise an illegal instruction exception
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* Privilege levels: `machine` mode, `user` mode (if enabled via `U` extension)
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* Official [RISC-V open-source architecture ID](https://github.com/riscv/riscv-isa-manual/blob/master/marchid.md)
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**RV32I base instruction set** (`I` extension):
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* ALU instructions: `LUI` `AUIPC` `ADDI` `SLTI` `SLTIU` `XORI` `ORI` `ANDI` `SLLI` `SRLI` `SRAI` `ADD` `SUB` `SLL` `SLT` `SLTU` `XOR` `SRL` `SRA` `OR` `AND`
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* Jump and branch instructions: `JAL` `JALR` `BEQ` `BNE` `BLT` `BGE` `BLTU` `BGEU`
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* Memory instructions: `LB` `LH` `LW` `LBU` `LHU` `SB` `SH` `SW`
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* System instructions: `ECALL` `EBREAK` `FENCE`
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* Pseudo-instructions are not listed
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**Compressed instructions** (`C` extension):
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* ALU instructions: `C.ADDI4SPN` `C.ADDI` `C.ADD` `C.ADDI16SP` `C.LI` `C.LUI` `C.SLLI` `C.SRLI` `C.SRAI` `C.ANDI` `C.SUB` `C.XOR` `C.OR` `C.AND` `C.MV` `C.NOP`
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* Jump and branch instructions: `C.J` `C.JAL` `C.JR` `C.JALR` `C.BEQZ` `C.BNEZ`
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* Memory instructions: `C.LW` `C.SW` `C.LWSP` `C.SWSP`
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* System instructions: `C.EBREAK` (only with `Zicsr` extension)
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* Pseudo-instructions are not listed
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**Embedded CPU version** (`E` extension):
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* Reduced register file (only the 16 lowest registers)
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**Integer multiplication and division hardware** (`M` extension):
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* Multiplication instructions: `MUL` `MULH` `MULHSU` `MULHU`
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* Division instructions: `DIV` `DIVU` `REM` `REMU`
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* By default, the multiplier and divider cores use an iterative bit-serial processing scheme
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* Multiplications can be mapped to DSPs via the `FAST_MUL_EN` generic to increase performance
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**Atomic memory access** (`A` extension):
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* Supported instructions: `LR.W` (load-reservate) `SC.W` (store-conditional)
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**Bit manipulation instructions** (`B` extension implying `Zbb` extension):
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* :warning: RISC-V `B` extension is not officially ratified yet!
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* Compatible to [v0.94-draft](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/bitmanip-draft.pdf) of the bit manipulation spec
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* Support via intrisc library (see [`sw/example/bit_manipulation`](https://github.com/stnolting/neorv32/tree/master/sw/example/bit_manipulation))
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* Only the `Zbb` base instructions subset is supported yet
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* Supported instructions: `CLZ` `CTZ` `CPOP` `SEXT.B` `SEXT.H` `MIN[U]` `MAX[U]` `ANDN` `ORN` `XNOR` `ROL` `ROR` `RORI` `zext`(*pseudo-instruction* for `PACK rd, rs, zero`) `rev8`(*pseudo-instruction* for `GREVI rd, rs, -8`) `orc.b`(*pseudo-instruction* for `GORCI rd, rs, 7`)
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**Privileged architecture / CSR access** (`Zicsr` extension):
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* Privilege levels: `M-mode` (Machine mode)
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* CSR access instructions: `CSRRW` `CSRRS` `CSRRC` `CSRRWI` `CSRRSI` `CSRRCI`
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* System instructions: `MRET` `WFI`
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* Pseudo-instructions are not listed
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* Counter CSRs: `[m]cycle[h]` `[m]instret[m]` `time[h]` `[m]hpmcounter*[h]`(3..31, configurable) `mcounteren` `mcountinhibit` `mhpmevent*`(3..31, configurable)
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* Machine CSRs: `mstatus[h]` `misa`(read-only!) `mie` `mtvec` `mscratch` `mepc` `mcause` `mtval` `mip` `mvendorid` [`marchid`](https://github.com/riscv/riscv-isa-manual/blob/master/marchid.md) `mimpid` `mhartid` `mzext`(custom)
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* Supported exceptions and interrupts:
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|
* Misaligned instruction address
|
214 |
38 |
zero_gravi |
* Instruction access fault (via unacknowledged bus access after timeout)
|
215 |
2 |
zero_gravi |
* Illegal instruction
|
216 |
4 |
zero_gravi |
* Breakpoint (via `ebreak` instruction)
|
217 |
2 |
zero_gravi |
* Load address misaligned
|
218 |
38 |
zero_gravi |
* Load access fault (via unacknowledged bus access after timeout)
|
219 |
4 |
zero_gravi |
* Store address misaligned
|
220 |
38 |
zero_gravi |
* Store access fault (via unacknowledged bus access after timeout)
|
221 |
40 |
zero_gravi |
* Environment call from U-mode (via `ecall` instruction in user mode)
|
222 |
|
|
* Environment call from M-mode (via `ecall` instruction in machine mode)
|
223 |
|
|
* Machine timer interrupt `mti` (via processor's MTIME unit / external signal)
|
224 |
15 |
zero_gravi |
* Machine software interrupt `msi` (via external signal)
|
225 |
|
|
* Machine external interrupt `mei` (via external signal)
|
226 |
|
|
* Four fast interrupt requests (custom extension)
|
227 |
2 |
zero_gravi |
|
228 |
15 |
zero_gravi |
**Privileged architecture / User mode** (`U` extension, requires `Zicsr` extension):
|
229 |
16 |
zero_gravi |
* Privilege levels: `M-mode` (Machine mode) + `U-mode` (User mode)
|
230 |
15 |
zero_gravi |
|
231 |
44 |
zero_gravi |
**Privileged architecture / Instruction stream synchronization** (`Zifencei` extension):
|
232 |
41 |
zero_gravi |
* System instructions: `FENCE.I` (among others, used to clear and reload instruction cache)
|
233 |
8 |
zero_gravi |
|
234 |
18 |
zero_gravi |
**Privileged architecture / Physical memory protection** (`PMP`, requires `Zicsr` extension):
|
235 |
44 |
zero_gravi |
* Configurable number of regions (0..63)
|
236 |
42 |
zero_gravi |
* Additional machine CSRs: `pmpcfg*`(0..15) `pmpaddr*`(0..63)
|
237 |
2 |
zero_gravi |
|
238 |
44 |
zero_gravi |
**Privileged architecture / Hardware performance monitors** (`HPM`, requires `Zicsr` extension):
|
239 |
|
|
* Configurable number of counters (0..29)
|
240 |
|
|
* Additional machine CSRs: `mhpmevent*`(3..31) `[m]hpmcounter*[h]`(3..31)
|
241 |
15 |
zero_gravi |
|
242 |
23 |
zero_gravi |
|
243 |
44 |
zero_gravi |
### :warning: Non-RISC-V-Compliant Issues and Limitations
|
244 |
|
|
|
245 |
40 |
zero_gravi |
* CPU and Processor are BIG-ENDIAN, but this should be no problem as the external memory bus interface provides big- and little-endian configurations
|
246 |
30 |
zero_gravi |
* `misa` CSR is read-only - no dynamic enabling/disabling of synthesized CPU extensions during runtime; for compatibility: write accesses (in m-mode) are ignored and do not cause an exception
|
247 |
42 |
zero_gravi |
* The physical memory protection (**PMP**) only supports `NAPOT` mode yet and a minimal granularity of 8 bytes
|
248 |
39 |
zero_gravi |
* The `A` extension only implements `lr.w` and `sc.w` instructions yet. However, these instructions are sufficient to emulate all further AMO operations
|
249 |
44 |
zero_gravi |
* The `mcause` trap code `0x80000000` (originally reserved in the RISC-V specs) is used to indicate a hardware reset (as "non-maskable interrupt")
|
250 |
|
|
* The bit manipulation extension is not yet officially ratified, but is expected to stay unchanged. There is no software support in the upstream GCC RISC-V port yet. However, an intrinsic library is provided to utilize the provided bit manipulation extension from C-language code (see [`sw/example/bit_manipulation`](https://github.com/stnolting/neorv32/tree/master/sw/example/bit_manipulation)). NEORV32's `B`/`Zbb` extension is compliant to spec. version "0.94-draft".
|
251 |
23 |
zero_gravi |
|
252 |
|
|
### NEORV32-Specific CPU Extensions
|
253 |
|
|
|
254 |
|
|
The NEORV32-specific extensions are always enabled and are indicated via the `X` bit in the `misa` CSR.
|
255 |
|
|
|
256 |
|
|
* Four *fast interrupt* request channels with according control/status bits in `mie` and `mip` and custom exception codes in `mcause`
|
257 |
|
|
* `mzext` CSR to check for implemented `Z*` CPU extensions (like `Zifencei`)
|
258 |
40 |
zero_gravi |
* All undefined/umimplemented/malformed/illegal instructions do raise an illegal instruction exception
|
259 |
23 |
zero_gravi |
|
260 |
|
|
|
261 |
|
|
|
262 |
2 |
zero_gravi |
## FPGA Implementation Results
|
263 |
|
|
|
264 |
23 |
zero_gravi |
### NEORV32 CPU
|
265 |
|
|
|
266 |
|
|
This chapter shows exemplary implementation results of the NEORV32 CPU for an **Intel Cyclone IV EP4CE22F17C6N FPGA** on
|
267 |
37 |
zero_gravi |
a DE0-nano board. The design was synthesized using **Intel Quartus Prime Lite 20.1** ("balanced implementation"). The timing
|
268 |
4 |
zero_gravi |
information is derived from the Timing Analyzer / Slow 1200mV 0C Model. If not otherwise specified, the default configuration
|
269 |
42 |
zero_gravi |
of the CPU's generics is assumed (e.g. no physical memory protection, no hardware performance monitors).
|
270 |
|
|
No constraints were used at all. The `u` and `Zifencei` extensions have a negligible impact on the hardware requirements.
|
271 |
2 |
zero_gravi |
|
272 |
45 |
zero_gravi |
Results generated for hardware version [`1.5.0.3`](https://github.com/stnolting/neorv32/blob/master/CHANGELOG.md).
|
273 |
2 |
zero_gravi |
|
274 |
44 |
zero_gravi |
| CPU Configuration | LEs | FFs | Memory bits | DSPs | f_max |
|
275 |
|
|
|:-----------------------------------------|:----------:|:--------:|:-----------:|:----:|:-------:|
|
276 |
45 |
zero_gravi |
| `rv32i` | 1190 | 512 | 1024 | 0 | 120 MHz |
|
277 |
|
|
| `rv32i` + `u` + `Zicsr` + `Zifencei` | 1927 | 903 | 1024 | 0 | 123 MHz |
|
278 |
|
|
| `rv32im` + `u` + `Zicsr` + `Zifencei` | 2471 | 1148 | 1024 | 0 | 120 MHz |
|
279 |
|
|
| `rv32imc` + `u` + `Zicsr` + `Zifencei` | 2716 | 1165 | 1024 | 0 | 120 MHz |
|
280 |
|
|
| `rv32imac` + `u` + `Zicsr` + `Zifencei` | 2736 | 1168 | 1024 | 0 | 120 MHz |
|
281 |
|
|
| `rv32imacb` + `u` + `Zicsr` + `Zifencei` | 3045 | 1260 | 1024 | 0 | 114 MHz |
|
282 |
2 |
zero_gravi |
|
283 |
39 |
zero_gravi |
Setups with enabled "embedded CPU extension" `E` show the same LUT and FF utilization and identical f_max. However, the size of the register file is cut in half.
|
284 |
2 |
zero_gravi |
|
285 |
39 |
zero_gravi |
|
286 |
23 |
zero_gravi |
### NEORV32 Processor-Internal Peripherals and Memories
|
287 |
|
|
|
288 |
45 |
zero_gravi |
Results generated for hardware version [`1.5.0.3`](https://github.com/stnolting/neorv32/blob/master/CHANGELOG.md).
|
289 |
11 |
zero_gravi |
|
290 |
25 |
zero_gravi |
| Module | Description | LEs | FFs | Memory bits | DSPs |
|
291 |
31 |
zero_gravi |
|:----------|:-----------------------------------------------------|----:|----:|------------:|-----:|
|
292 |
37 |
zero_gravi |
| BOOT ROM | Bootloader ROM (default 4kB) | 3 | 1 | 32 768 | 0 |
|
293 |
40 |
zero_gravi |
| BUSSWITCH | Mux for CPU I & D interfaces | 65 | 8 | 0 | 0 |
|
294 |
45 |
zero_gravi |
| i-CACHE | Proc.-int. nstruction cache (default 1x4x64 bytes) | 234 | 156 | 8 192 | 0 |
|
295 |
34 |
zero_gravi |
| CFU0 | Custom functions unit 0 | - | - | - | - |
|
296 |
|
|
| CFU1 | Custom functions unit 1 | - | - | - | - |
|
297 |
39 |
zero_gravi |
| DMEM | Processor-internal data memory (default 8kB) | 6 | 2 | 65 536 | 0 |
|
298 |
40 |
zero_gravi |
| GPIO | General purpose input/output ports | 67 | 65 | 0 | 0 |
|
299 |
39 |
zero_gravi |
| IMEM | Processor-internal instruction memory (default 16kb) | 6 | 2 | 131 072 | 0 |
|
300 |
40 |
zero_gravi |
| MTIME | Machine system timer | 274 | 166 | 0 | 0 |
|
301 |
39 |
zero_gravi |
| PWM | Pulse-width modulation controller | 71 | 69 | 0 | 0 |
|
302 |
40 |
zero_gravi |
| SPI | Serial peripheral interface | 138 | 124 | 0 | 0 |
|
303 |
|
|
| SYSINFO | System configuration information memory | 11 | 10 | 0 | 0 |
|
304 |
31 |
zero_gravi |
| TRNG | True random number generator | 132 | 105 | 0 | 0 |
|
305 |
40 |
zero_gravi |
| TWI | Two-wire interface | 77 | 46 | 0 | 0 |
|
306 |
|
|
| UART | Universal asynchronous receiver/transmitter | 176 | 132 | 0 | 0 |
|
307 |
|
|
| WDT | Watchdog timer | 60 | 45 | 0 | 0 |
|
308 |
39 |
zero_gravi |
| WISHBONE | External memory interface | 129 | 104 | 0 | 0 |
|
309 |
2 |
zero_gravi |
|
310 |
|
|
|
311 |
23 |
zero_gravi |
### NEORV32 Processor - Exemplary FPGA Setups
|
312 |
6 |
zero_gravi |
|
313 |
34 |
zero_gravi |
Exemplary processor implementation results for different FPGA platforms. The processor setup uses *the default peripheral configuration* (like no _CFUs_ and no _TRNG_),
|
314 |
23 |
zero_gravi |
no external memory interface and only internal instruction and data memories. IMEM uses 16kB and DMEM uses 8kB memory space. The setup's top entity connects most of the
|
315 |
11 |
zero_gravi |
processor's [top entity](https://github.com/stnolting/neorv32/blob/master/rtl/core/neorv32_top.vhd) signals
|
316 |
40 |
zero_gravi |
to FPGA pins - except for the Wishbone bus and the interrupt signals. The "default" strategy of each toolchain is used.
|
317 |
6 |
zero_gravi |
|
318 |
40 |
zero_gravi |
Results generated for hardware version [`1.4.9.0`](https://github.com/stnolting/neorv32/blob/master/CHANGELOG.md).
|
319 |
6 |
zero_gravi |
|
320 |
40 |
zero_gravi |
| Vendor | FPGA | Board | Toolchain | CPU Configuration | LUT / LE | FF / REG | DSP | Memory Bits | BRAM / EBR | SPRAM | Frequency |
|
321 |
|
|
|:--------|:----------------------------------|:-----------------|:---------------------------|:-----------------------------------------------|:-----------|:-----------|:-------|:-------------|:-----------|:---------|--------------:|
|
322 |
|
|
| Intel | Cyclone IV `EP4CE22F17C6N` | Terasic DE0-Nano | Quartus Prime Lite 20.1 | `rv32imc` + `u` + `Zicsr` + `Zifencei` | 3813 (17%) | 1904 (8%) | 0 (0%) | 231424 (38%) | - | - | 119 MHz |
|
323 |
|
|
| Lattice | iCE40 UltraPlus `iCE40UP5K-SG48I` | Upduino v2.0 | Radiant 2.1 (Synplify Pro) | `rv32ic` + `u` + `Zicsr` + `Zifencei` | 4397 (83%) | 1679 (31%) | 0 (0%) | - | 12 (40%) | 4 (100%) | *c* 22.15 MHz |
|
324 |
|
|
| Xilinx | Artix-7 `XC7A35TICSG324-1L` | Arty A7-35T | Vivado 2019.2 | `rv32imc` + `u` + `Zicsr` + `Zifencei` + `PMP` | 2465 (12%) | 1912 (5%) | 0 (0%) | - | 8 (16%) | - | *c* 100 MHz |
|
325 |
2 |
zero_gravi |
|
326 |
23 |
zero_gravi |
**_Notes_**
|
327 |
20 |
zero_gravi |
* The Lattice iCE40 UltraPlus setup uses the FPGA's SPRAM memory primitives for the internal IMEM and DMEM (each 64kb).
|
328 |
12 |
zero_gravi |
The FPGA-specific memory components can be found in [`rtl/fpga_specific`](https://github.com/stnolting/neorv32/blob/master/rtl/fpga_specific/lattice_ice40up).
|
329 |
|
|
* The clock frequencies marked with a "c" are constrained clocks. The remaining ones are _f_max_ results from the place and route timing reports.
|
330 |
11 |
zero_gravi |
* The Upduino and the Arty board have on-board SPI flash memories for storing the FPGA configuration. These device can also be used by the default NEORV32
|
331 |
|
|
bootloader to store and automatically boot an application program after reset (both tested successfully).
|
332 |
40 |
zero_gravi |
* The setups with `PMP` implement 2 regions with a minimal granularity of 64kB.
|
333 |
42 |
zero_gravi |
* No HPM counters are implemented.
|
334 |
2 |
zero_gravi |
|
335 |
22 |
zero_gravi |
|
336 |
|
|
|
337 |
2 |
zero_gravi |
## Performance
|
338 |
|
|
|
339 |
|
|
### CoreMark Benchmark
|
340 |
|
|
|
341 |
|
|
The [CoreMark CPU benchmark](https://www.eembc.org/coremark) was executed on the NEORV32 and is available in the
|
342 |
|
|
[sw/example/coremark](https://github.com/stnolting/neorv32/blob/master/sw/example/coremark) project folder. This benchmark
|
343 |
|
|
tests the capabilities of a CPU itself rather than the functions provided by the whole system / SoC.
|
344 |
|
|
|
345 |
|
|
~~~
|
346 |
|
|
**Configuration**
|
347 |
45 |
zero_gravi |
Hardware: 32kB IMEM, 16kB DMEM, no caches, 100MHz clock
|
348 |
38 |
zero_gravi |
CoreMark: 2000 iterations, MEM_METHOD is MEM_STACK
|
349 |
|
|
Compiler: RISCV32-GCC 10.1.0 (rv32i toolchain)
|
350 |
|
|
Compiler flags: default, see makefile
|
351 |
|
|
Peripherals: UART for printing the results
|
352 |
2 |
zero_gravi |
~~~
|
353 |
|
|
|
354 |
42 |
zero_gravi |
Results generated for hardware version [`1.4.9.8`](https://github.com/stnolting/neorv32/blob/master/CHANGELOG.md).
|
355 |
|
|
|
356 |
|
|
| CPU (including `Zicsr`) | Executable Size | Optimization | CoreMark Score | CoreMarks/MHz |
|
357 |
34 |
zero_gravi |
|:--------------------------------------------|:---------------:|:------------:|:--------------:|:-------------:|
|
358 |
42 |
zero_gravi |
| `rv32i` | 28 756 bytes | `-O3` | 36.36 | **0.3636** |
|
359 |
|
|
| `rv32im` | 27 516 bytes | `-O3` | 68.97 | **0.6897** |
|
360 |
|
|
| `rv32imc` | 22 008 bytes | `-O3` | 68.97 | **0.6897** |
|
361 |
|
|
| `rv32imc` + `FAST_MUL_EN` | 22 008 bytes | `-O3` | 86.96 | **0.8696** |
|
362 |
|
|
| `rv32imc` + `FAST_MUL_EN` + `FAST_SHIFT_EN` | 22 008 bytes | `-O3` | 90.91 | **0.9091** |
|
363 |
2 |
zero_gravi |
|
364 |
34 |
zero_gravi |
The `FAST_MUL_EN` configuration uses DSPs for the multiplier of the `M` extension (enabled via the `FAST_MUL_EN` generic). The `FAST_SHIFT_EN` configuration
|
365 |
|
|
uses a barrel shifter for CPU shift operations (enabled via the `FAST_SHIFT_EN` generic).
|
366 |
2 |
zero_gravi |
|
367 |
31 |
zero_gravi |
When the `C` extension is enabled, branches to an unaligned uncompressed instruction require additional instruction fetch cycles.
|
368 |
22 |
zero_gravi |
|
369 |
34 |
zero_gravi |
|
370 |
2 |
zero_gravi |
### Instruction Cycles
|
371 |
|
|
|
372 |
11 |
zero_gravi |
The NEORV32 CPU is based on a two-stages pipelined architecutre. Each stage uses a multi-cycle processing scheme. Hence,
|
373 |
9 |
zero_gravi |
each instruction requires several clock cycles to execute (2 cycles for ALU operations, ..., 40 cycles for divisions).
|
374 |
|
|
The average CPI (cycles per instruction) depends on the instruction mix of a specific applications and also on the available
|
375 |
42 |
zero_gravi |
CPU extensions. *By default* the CPU-internal shifter (e.g. for the `SLL` instruction) as well as the multiplier and divider of the
|
376 |
2 |
zero_gravi |
`M` extension use a bit-serial approach and require several cycles for completion.
|
377 |
|
|
|
378 |
6 |
zero_gravi |
The following table shows the performance results for successfully running 2000 CoreMark
|
379 |
9 |
zero_gravi |
iterations, which reflects a pretty good "real-life" work load. The average CPI is computed by
|
380 |
12 |
zero_gravi |
dividing the total number of required clock cycles (only the timed core to avoid distortion due to IO wait cycles; sampled via the `cycle[h]` CSRs)
|
381 |
19 |
zero_gravi |
by the number of executed instructions (`instret[h]` CSRs). The executables were generated using optimization `-O3`.
|
382 |
2 |
zero_gravi |
|
383 |
42 |
zero_gravi |
Results generated for hardware version [`1.4.9.8`](https://github.com/stnolting/neorv32/blob/master/CHANGELOG.md).
|
384 |
2 |
zero_gravi |
|
385 |
42 |
zero_gravi |
| CPU (including `Zicsr`) | Required Clock Cycles | Executed Instructions | Average CPI |
|
386 |
34 |
zero_gravi |
|:--------------------------------------------|----------------------:|----------------------:|:-----------:|
|
387 |
42 |
zero_gravi |
| `rv32i` | 5 595 750 503 | 1 466 028 607 | **3.82** |
|
388 |
|
|
| `rv32im` | 2 966 086 503 | 598 651 143 | **4.95** |
|
389 |
|
|
| `rv32imc` | 2 981 786 734 | 611 814 918 | **4.87** |
|
390 |
|
|
| `rv32imc` + `FAST_MUL_EN` | 2 399 234 734 | 611 814 918 | **3.92** |
|
391 |
|
|
| `rv32imc` + `FAST_MUL_EN` + `FAST_SHIFT_EN` | 2 265 135 174 | 611 814 948 | **3.70** |
|
392 |
2 |
zero_gravi |
|
393 |
34 |
zero_gravi |
The `FAST_MUL_EN` configuration uses DSPs for the multiplier of the `M` extension (enabled via the `FAST_MUL_EN` generic). The `FAST_SHIFT_EN` configuration
|
394 |
|
|
uses a barrel shifter for CPU shift operations (enabled via the `FAST_SHIFT_EN` generic).
|
395 |
|
|
|
396 |
36 |
zero_gravi |
When the `C` extension is enabled branches to an unaligned uncompressed instruction require additional instruction fetch cycles.
|
397 |
12 |
zero_gravi |
|
398 |
22 |
zero_gravi |
|
399 |
31 |
zero_gravi |
|
400 |
14 |
zero_gravi |
## Top Entities
|
401 |
2 |
zero_gravi |
|
402 |
36 |
zero_gravi |
The top entity of the **NEORV32 Processor** (SoC) is [`rtl/core/neorv32_top.vhd`](https://github.com/stnolting/neorv32/blob/master/rtl/core/neorv32_top.vhd).
|
403 |
2 |
zero_gravi |
|
404 |
36 |
zero_gravi |
All signals of the top entity are of type *std_ulogic* or *std_ulogic_vector*, respectively
|
405 |
34 |
zero_gravi |
(except for the processor's TWI signals, which are of type *std_logic*). Leave all unused output ports unconnected (`open`) and tie all unused
|
406 |
|
|
input ports to zero (`'0'` or `(others => '0')`, respectively).
|
407 |
14 |
zero_gravi |
|
408 |
36 |
zero_gravi |
Use the top's generics to configure the system according to your needs. Each generic is initilized with the default configuration.
|
409 |
34 |
zero_gravi |
Detailed information regarding the interface signals and configuration generics can be found in
|
410 |
40 |
zero_gravi |
the [:page_facing_up: NEORV32 data sheet](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/NEORV32.pdf) (pdf).
|
411 |
22 |
zero_gravi |
|
412 |
23 |
zero_gravi |
|
413 |
36 |
zero_gravi |
### Using the CPU in Stand-Alone Mode
|
414 |
23 |
zero_gravi |
|
415 |
36 |
zero_gravi |
If you do not want to use the NEORV32 processor setup, you can also use the CPU in stand-alone mode and build your own system around it.
|
416 |
|
|
The top entity of the stand-alone **NEORV32 CPU** is [`rtl/core/neorv32_cpu.vhd`](https://github.com/stnolting/neorv32/blob/master/rtl/core/neorv32_cpu.vhd).
|
417 |
|
|
Note that the CPU uses a proprietary interface for accessing data and instruction memory. More information can be found in the
|
418 |
40 |
zero_gravi |
[:page_facing_up: NEORV32 data sheet](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/NEORV32.pdf).
|
419 |
14 |
zero_gravi |
|
420 |
36 |
zero_gravi |
:warning: It is recommended to use the processor setup even if you only want to use the CPU. Simply disable all the processor-internal modules via the generics
|
421 |
|
|
and you will get a "CPU wrapper" that provides a minimal CPU environment and an external memory interface (like AXI4). This setup also allows to further use the default
|
422 |
|
|
bootloader and application makefiles. From this base you can start building your own processor system.
|
423 |
2 |
zero_gravi |
|
424 |
36 |
zero_gravi |
|
425 |
|
|
### Alternative Top Entities
|
426 |
|
|
|
427 |
|
|
*Alternative top entities*, like the simplified ["hello world" test setup](#Create-a-new-Hardware-Project) or CPU/Processor
|
428 |
|
|
wrappers with resolved port signal types (i.e. *std_logic*), can be found in [`rtl/top_templates`](https://github.com/stnolting/neorv32/blob/master/rtl/top_templates).
|
429 |
|
|
|
430 |
|
|
|
431 |
35 |
zero_gravi |
### AXI4 Connectivity
|
432 |
22 |
zero_gravi |
|
433 |
35 |
zero_gravi |
Via the [`rtl/top_templates/neorv32_top_axi4lite.vhd`](https://github.com/stnolting/neorv32/blob/master/rtl/top_templates/neorv32_top_axi4lite.vhd)
|
434 |
|
|
wrapper the NEORV32 provides an **AXI4-Lite** compatible master interface. This wrapper instantiates the default
|
435 |
|
|
[NEORV32 processor top entitiy](https://github.com/stnolting/neorv32/blob/master/rtl/core/neorv32_top.vhd) and implements a Wishbone to AXI4-Lite bridge.
|
436 |
2 |
zero_gravi |
|
437 |
35 |
zero_gravi |
The AXI4-Lite interface has been tested using Xilinx Vivado 19.2 block designer:
|
438 |
|
|
|
439 |
|
|
![AXI-SoC](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/figures/neorv32_axi_soc.png)
|
440 |
|
|
|
441 |
|
|
The processor was packed as custom IP using `neorv32_top_axi4lite.vhd` as top entity. The AXI interface is automatically detected by the packager.
|
442 |
|
|
All remaining IO interfaces are available as custom signals. The configuration generics are available via the "customize IP" dialog.
|
443 |
|
|
In the figure above the resulting IP block is named "neorv32_top_axi4lite_v1_0".
|
444 |
|
|
*(Note: Use Syntheiss option "global" when generating the block design to maintain the internal TWI tri-state drivers.)*
|
445 |
|
|
|
446 |
|
|
The setup uses an AXI interconnect to attach two block RAMs to the processor. Since the processor in this example is configured *without* IMEM and DMEM,
|
447 |
|
|
the attached block RAMs are used for storing instructions and data: the first RAM is used as instruction memory
|
448 |
|
|
and is mapped to address `0x00000000 - 0x00003fff` (16kB), the second RAM is used as data memory and is mapped to address `0x80000000 - 0x80001fff` (8kB).
|
449 |
|
|
|
450 |
|
|
|
451 |
|
|
|
452 |
2 |
zero_gravi |
## Getting Started
|
453 |
|
|
|
454 |
|
|
This overview is just a short excerpt from the *Let's Get It Started* section of the NEORV32 documentary:
|
455 |
|
|
|
456 |
40 |
zero_gravi |
[:page_facing_up: NEORV32 data sheet](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/NEORV32.pdf)
|
457 |
2 |
zero_gravi |
|
458 |
|
|
|
459 |
14 |
zero_gravi |
### Toolchain
|
460 |
2 |
zero_gravi |
|
461 |
|
|
At first you need the **RISC-V GCC toolchain**. You can either [download the sources](https://github.com/riscv/riscv-gnu-toolchain)
|
462 |
|
|
and build the toolchain by yourself, or you can download a prebuilt one and install it.
|
463 |
|
|
|
464 |
23 |
zero_gravi |
To build the toolchain by yourself, follow the official [build instructions](https://github.com/riscv/riscv-gnu-toolchain).
|
465 |
14 |
zero_gravi |
Make sure to use the `ilp32` or `ilp32e` ABI.
|
466 |
2 |
zero_gravi |
|
467 |
15 |
zero_gravi |
**Alternatively**, you can download a prebuilt toolchain. I have uploaded the toolchains I am using to GitHub. These toolchains
|
468 |
40 |
zero_gravi |
were compiled on a 64-bit x86 Ubuntu 20.04 LTS (Ubuntu on Windows, actually). Download the toolchain of choice:
|
469 |
|
|
[:octocat: github.com/stnolting/riscv_gcc_prebuilt](https://github.com/stnolting/riscv_gcc_prebuilt)
|
470 |
2 |
zero_gravi |
|
471 |
45 |
zero_gravi |
You can also use the toolchains provided by [SiFive](https://github.com/sifive/freedom-tools/releases). These are 64-bit toolchains that can also emit 32-bit
|
472 |
|
|
RISC-V code. They were compiled for more sophisticated machines (`imac`) so the according hardware extensions are *mandatory*
|
473 |
2 |
zero_gravi |
|
474 |
45 |
zero_gravi |
:warning: Keep in mind that – for instance – a `rv32imc` toolchain only provides library code compiled with compressed and
|
475 |
|
|
`mul`/`div` instructions! Hence, this code cannot be executed (without emulation) on an architecture without these extensions!
|
476 |
|
|
|
477 |
|
|
|
478 |
22 |
zero_gravi |
### Dowload the NEORV32 Project
|
479 |
2 |
zero_gravi |
|
480 |
23 |
zero_gravi |
Get the sources of the NEORV32 Processor project. The simplest way is using `git clone` (suggested for easy project updates via `git pull`):
|
481 |
12 |
zero_gravi |
|
482 |
2 |
zero_gravi |
$ git clone https://github.com/stnolting/neorv32.git
|
483 |
|
|
|
484 |
23 |
zero_gravi |
Alternatively, you can either download a specific [release](https://github.com/stnolting/neorv32/releases) or get the most recent version
|
485 |
|
|
of this project as [`*.zip` file](https://github.com/stnolting/neorv32/archive/master.zip).
|
486 |
2 |
zero_gravi |
|
487 |
22 |
zero_gravi |
|
488 |
|
|
### Create a new Hardware Project
|
489 |
|
|
|
490 |
23 |
zero_gravi |
Create a new project with your FPGA design tool of choice. Add all the `*.vhd` files from the [`rtl/core`](https://github.com/stnolting/neorv32/blob/master/rtl)
|
491 |
|
|
folder to this project. Make sure to add these files to a **new design library** called `neorv32`.
|
492 |
|
|
|
493 |
40 |
zero_gravi |
You can either instantiate the [processor's top entity](https://github.com/stnolting/neorv32/blob/master/rtl/core/neorv32_top.vhd) or one of its
|
494 |
36 |
zero_gravi |
[wrappers](https://github.com/stnolting/neorv32/blob/master/rtl/top_templates) in your own project. If you just want to try out the processor,
|
495 |
|
|
you can use the simple [test setup](https://github.com/stnolting/neorv32/blob/master/rtl/top_templates/neorv32_test_setup.vhd) as top entity.
|
496 |
2 |
zero_gravi |
|
497 |
40 |
zero_gravi |
![neorv32 test setup](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/figures/neorv32_test_setup.png)
|
498 |
|
|
|
499 |
|
|
|
500 |
33 |
zero_gravi |
This test setup instantiates the processor and implements most of the peripherals and some ISA extensions. Only the UART lines, clock, reset and some GPIO output signals are
|
501 |
25 |
zero_gravi |
propagated as actual entity signals. Basically, it is a FPGA "hello world" example:
|
502 |
23 |
zero_gravi |
|
503 |
2 |
zero_gravi |
```vhdl
|
504 |
9 |
zero_gravi |
entity neorv32_test_setup is
|
505 |
|
|
port (
|
506 |
|
|
-- Global control --
|
507 |
|
|
clk_i : in std_ulogic := '0'; -- global clock, rising edge
|
508 |
|
|
rstn_i : in std_ulogic := '0'; -- global reset, low-active, async
|
509 |
|
|
-- GPIO --
|
510 |
|
|
gpio_o : out std_ulogic_vector(7 downto 0); -- parallel output
|
511 |
|
|
-- UART --
|
512 |
|
|
uart_txd_o : out std_ulogic; -- UART send data
|
513 |
|
|
uart_rxd_i : in std_ulogic := '0' -- UART receive data
|
514 |
|
|
);
|
515 |
|
|
end neorv32_test_setup;
|
516 |
2 |
zero_gravi |
```
|
517 |
|
|
|
518 |
|
|
|
519 |
23 |
zero_gravi |
### Check the Toolchain
|
520 |
2 |
zero_gravi |
|
521 |
11 |
zero_gravi |
Make sure `GNU Make` and a native `GCC` compiler are installed. To test the installation of the RISC-V toolchain navigate to an example project like
|
522 |
2 |
zero_gravi |
`sw/example/blink_led` and run:
|
523 |
|
|
|
524 |
|
|
neorv32/sw/example/blink_led$ make check
|
525 |
|
|
|
526 |
23 |
zero_gravi |
|
527 |
|
|
### Compiling an Example Program
|
528 |
|
|
|
529 |
9 |
zero_gravi |
The NEORV32 project includes some [example programs](https://github.com/stnolting/neorv32/tree/master/sw/example) from
|
530 |
|
|
which you can start your own application. Simply compile one of these projects. This will create a NEORV32
|
531 |
23 |
zero_gravi |
*executable* `neorv32_exe.bin` in the same folder:
|
532 |
2 |
zero_gravi |
|
533 |
23 |
zero_gravi |
neorv32/sw/example/blink_led$ make clean_all exe
|
534 |
2 |
zero_gravi |
|
535 |
23 |
zero_gravi |
|
536 |
|
|
### Upload the Executable via the Bootloader
|
537 |
|
|
|
538 |
34 |
zero_gravi |
You can upload a generated executable directly from the command line using the makefile's `upload` target. Replace `/dev/ttyUSB0` with
|
539 |
|
|
the according serial port.
|
540 |
|
|
|
541 |
|
|
sw/exeample/blink_example$ make COM_PORT=/dev/ttyUSB0` upload
|
542 |
|
|
|
543 |
|
|
A more "secure" way is to use a dedicated terminal program. This allows to directly interact with the bootloader console.
|
544 |
23 |
zero_gravi |
Connect your FPGA board via UART to your computer and open the according port to interface with the NEORV32 bootloader. The bootloader
|
545 |
2 |
zero_gravi |
uses the following default UART configuration:
|
546 |
|
|
|
547 |
32 |
zero_gravi |
* 19200 Baud
|
548 |
|
|
* 8 data bits
|
549 |
|
|
* 1 stop bit
|
550 |
|
|
* No parity bits
|
551 |
|
|
* No transmission / flow control protocol (raw bytes only)
|
552 |
|
|
* Newline on `\r\n` (carriage return & newline) - also for sent data
|
553 |
2 |
zero_gravi |
|
554 |
23 |
zero_gravi |
Use the bootloader console to upload the `neorv32_exe.bin` executable and run your application image.
|
555 |
2 |
zero_gravi |
|
556 |
9 |
zero_gravi |
```
|
557 |
43 |
zero_gravi |
<< NEORV32 Bootloader >>
|
558 |
|
|
|
559 |
|
|
BLDV: Nov 7 2020
|
560 |
|
|
HWV: 0x01040606
|
561 |
|
|
CLK: 0x0134FD90 Hz
|
562 |
|
|
USER: 0x0001CE40
|
563 |
|
|
MISA: 0x42801104
|
564 |
|
|
PROC: 0x03FF0035
|
565 |
|
|
IMEM: 0x00010000 bytes @ 0x00000000
|
566 |
|
|
DMEM: 0x00010000 bytes @ 0x80000000
|
567 |
|
|
|
568 |
|
|
Autoboot in 8s. Press key to abort.
|
569 |
|
|
Aborted.
|
570 |
|
|
|
571 |
|
|
Available CMDs:
|
572 |
|
|
h: Help
|
573 |
|
|
r: Restart
|
574 |
|
|
u: Upload
|
575 |
|
|
s: Store to flash
|
576 |
|
|
l: Load from flash
|
577 |
|
|
e: Execute
|
578 |
|
|
CMD:> u
|
579 |
|
|
Awaiting neorv32_exe.bin... OK
|
580 |
|
|
CMD:> e
|
581 |
|
|
Booting...
|
582 |
|
|
|
583 |
|
|
Blinking LED demo program
|
584 |
9 |
zero_gravi |
```
|
585 |
2 |
zero_gravi |
|
586 |
40 |
zero_gravi |
Going further: Take a look at the _Let's Get It Started!_ chapter of the [:page_facing_up: NEORV32 data sheet](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/NEORV32.pdf).
|
587 |
2 |
zero_gravi |
|
588 |
|
|
|
589 |
|
|
|
590 |
40 |
zero_gravi |
## Contribute/Feedback/Questions
|
591 |
2 |
zero_gravi |
|
592 |
9 |
zero_gravi |
I'm always thankful for help! So if you have any questions, bug reports, ideas or if you want to give some kind of feedback, feel free
|
593 |
40 |
zero_gravi |
to [:bulb: open a new issue](https://github.com/stnolting/neorv32/issues), start a new [:sparkles: discussion on GitHub](https://github.com/stnolting/neorv32/discussions)
|
594 |
|
|
or directly [:e-mail: drop me a line](mailto:stnolting@gmail.com).
|
595 |
2 |
zero_gravi |
|
596 |
40 |
zero_gravi |
If you'd like to directly contribute to this repository:
|
597 |
22 |
zero_gravi |
|
598 |
40 |
zero_gravi |
0. :star: this repository ;)
|
599 |
|
|
1. Check out the project's [code of conduct](https://github.com/stnolting/neorv32/tree/master/CODE_OF_CONDUCT.md)
|
600 |
|
|
2. [Fork](https://github.com/stnolting/neorv32/fork) this repository and clone the fork
|
601 |
|
|
3. Create a feature branch in your fork: `git checkout -b awesome_new_feature_branch`
|
602 |
|
|
4. Create a new remote for the upstream repo: `git remote add upstream https://github.com/stnolting/neorv32`
|
603 |
|
|
5. Commit your modifications: `git commit -m "Awesome new feature!"`
|
604 |
|
|
6. Push to the branch: `git push origin awesome_new_feature_branch`
|
605 |
|
|
7. Create a new [pull request](https://github.com/stnolting/neorv32/pulls)
|
606 |
2 |
zero_gravi |
|
607 |
40 |
zero_gravi |
|
608 |
11 |
zero_gravi |
## Legal
|
609 |
2 |
zero_gravi |
|
610 |
12 |
zero_gravi |
This project is released under the BSD 3-Clause license. No copyright infringement intended.
|
611 |
11 |
zero_gravi |
Other implied or used projects might have different licensing - see their documentation to get more information.
|
612 |
|
|
|
613 |
37 |
zero_gravi |
#### Citing
|
614 |
11 |
zero_gravi |
|
615 |
34 |
zero_gravi |
If you are using the NEORV32 or some parts of the project in some kind of publication, please cite it as follows:
|
616 |
2 |
zero_gravi |
|
617 |
34 |
zero_gravi |
> S. Nolting, "The NEORV32 Processor", github.com/stnolting/neorv32
|
618 |
2 |
zero_gravi |
|
619 |
9 |
zero_gravi |
#### BSD 3-Clause License
|
620 |
2 |
zero_gravi |
|
621 |
42 |
zero_gravi |
Copyright (c) 2021, Stephan Nolting. All rights reserved.
|
622 |
2 |
zero_gravi |
|
623 |
|
|
Redistribution and use in source and binary forms, with or without modification, are
|
624 |
|
|
permitted provided that the following conditions are met:
|
625 |
|
|
|
626 |
|
|
1. Redistributions of source code must retain the above copyright notice, this list of
|
627 |
|
|
conditions and the following disclaimer.
|
628 |
|
|
2. Redistributions in binary form must reproduce the above copyright notice, this list of
|
629 |
|
|
conditions and the following disclaimer in the documentation and/or other materials
|
630 |
|
|
provided with the distribution.
|
631 |
|
|
3. Neither the name of the copyright holder nor the names of its contributors may be used to
|
632 |
|
|
endorse or promote products derived from this software without specific prior written
|
633 |
|
|
permission.
|
634 |
|
|
|
635 |
|
|
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
|
636 |
|
|
OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
|
637 |
|
|
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
638 |
|
|
COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
|
639 |
|
|
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
|
640 |
|
|
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
641 |
|
|
AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
|
642 |
|
|
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
|
643 |
|
|
OF THE POSSIBILITY OF SUCH DAMAGE.
|
644 |
|
|
|
645 |
|
|
|
646 |
9 |
zero_gravi |
#### Limitation of Liability for External Links
|
647 |
|
|
|
648 |
36 |
zero_gravi |
Our website contains links to the websites of third parties ("external links"). As the
|
649 |
9 |
zero_gravi |
content of these websites is not under our control, we cannot assume any liability for
|
650 |
|
|
such external content. In all cases, the provider of information of the linked websites
|
651 |
|
|
is liable for the content and accuracy of the information provided. At the point in time
|
652 |
|
|
when the links were placed, no infringements of the law were recognisable to us. As soon
|
653 |
|
|
as an infringement of the law becomes known to us, we will immediately remove the
|
654 |
|
|
link in question.
|
655 |
|
|
|
656 |
|
|
|
657 |
11 |
zero_gravi |
#### Proprietary Notice
|
658 |
9 |
zero_gravi |
|
659 |
2 |
zero_gravi |
"Artix" and "Vivado" are trademarks of Xilinx Inc.
|
660 |
|
|
|
661 |
45 |
zero_gravi |
"Cyclone" and "Quartus Prime Lite" are trademarks of Intel Corporation.
|
662 |
2 |
zero_gravi |
|
663 |
35 |
zero_gravi |
"iCE40", "UltraPlus" and "Radiant" are trademarks of Lattice Semiconductor Corporation.
|
664 |
11 |
zero_gravi |
|
665 |
35 |
zero_gravi |
"AXI", "AXI4" and "AXI4-Lite" are trademarks of Arm Holdings plc.
|
666 |
2 |
zero_gravi |
|
667 |
|
|
|
668 |
|
|
|
669 |
18 |
zero_gravi |
## Acknowledgements
|
670 |
9 |
zero_gravi |
|
671 |
18 |
zero_gravi |
[![RISC-V](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/figures/riscv_logo.png)](https://riscv.org/)
|
672 |
|
|
|
673 |
23 |
zero_gravi |
[RISC-V](https://riscv.org/) - Instruction Sets Want To Be Free!
|
674 |
11 |
zero_gravi |
|
675 |
43 |
zero_gravi |
Continous integration provided by [:octocat: GitHub Actions](https://github.com/features/actions) and powered by [GHDL](https://github.com/ghdl/ghdl).
|
676 |
2 |
zero_gravi |
|
677 |
|
|
![Open Source Hardware Logo https://www.oshwa.org](https://raw.githubusercontent.com/stnolting/neorv32/master/docs/figures/oshw_logo.png)
|
678 |
|
|
|
679 |
|
|
This project is not affiliated with or endorsed by the Open Source Initiative (https://www.oshwa.org / https://opensource.org).
|
680 |
|
|
|
681 |
32 |
zero_gravi |
--------
|
682 |
2 |
zero_gravi |
|
683 |
36 |
zero_gravi |
Made with :coffee: in Hannover, Germany :eu:
|