Riv Emu

Easily extendable library to emulate RISC-V.

• Git
• Issues & Bugs

Features

List of planed and implemented features. And a list of features that are considered stable

Implementation status

• rv32i
• Zicsr
  • Machine
  • Supervisor
  • User
• A
• M
• F
• D

Release status

• rv32i
• Zicsr
  • Machine
  • Supervisor
  • User
• A
• M
• F
• D

Installation

cargo install --git "https://github.com/whirlpool-galaxy/RivEmu.git" --branch "latest"

Usage

run_riv_emu <path/to/memory/image> [<load address in hex> [<number of cycles>]]

Creation of a memory image

clang --target=riscv32 -march=rv32i -c -o <output/file> <input/file>

ld.lld -nostdlib --script=<linker/script> -o <output/file> <input/files>+

llvm-objcopy -O binary <input/file> <output/file>

Example linker script and startup.s

rivemu_rv32i.ld

    ENTRY(IRQ_reset)

    MEMORY
    {
        MEM (rwx): org = 0x00000000, len = 1M
    }

    SECTIONS
    {  
        .text : {
            . = 0x00000000;
            *(.irq)

            . = 0x00000040;
            */rivemu_rv32i_startup.o (.text)
            */rivemu_rv32i_startup.o (.data)
            */rivemu_rv32i_startup.o (.bss)

            *(.text)
            *(.data)
            *(.bss)
            *(.rodata)

            *(.text*)
            *(.data*)
            *(.bss*)
            *(.rodata*)
        }
    }

rivemu_rv32i_startup.s

    .global IRQH_reset
    .weak IRQH_reset
    
    .global IRQH_ebreak
    .weak IRQH_ebreak
    
    .global IRQH_m_ecall
    .weak IRQH_m_ecall
    
    .global IRQH_s_ecall
    .weak IRQH_s_ecall
    
    .global IRQH_u_ecall
    .weak IRQH_u_ecall
    
    .global IRQH_illegal_instruction
    .weak IRQH_illegal_instruction
    
    .global IRQH_instruction_address_misaligned
    .weak IRQH_instruction_address_misaligned
    
    .section .irq
    .word IRQH_reset
    .word IRQH_ebreak
    .word IRQH_m_ecall
    .word IRQH_s_ecall
    .word IRQH_u_ecall
    .word IRQH_illegal_instruction
    .word IRQH_instruction_address_misaligned
    .word 0
    .word 0
    .word 0
    .word 0
    .word 0
    .word 0
    .word 0
    .word 0
    .word 0
    
    .text
    
    IRQH_reset:
        call main
        j END_OF_CODE
    
    IRQH_ebreak:
        j END_OF_CODE
    
    IRQH_ecall:
        j END_OF_CODE
    
    IRQH_illegal_instruction:
        j END_OF_CODE
    
    IRQH_instruction_address_misaligned:
        j END_OF_CODE
    
    END_OF_CODE:
        j END_OF_CODE

Module diagram

Authors and Copyright

Copyright (C) 2022 Jonathan Schild - MIT License

• Jonathan Schild