Neovim configuration for RISC-V Assembly

[WillLillis]

Discussed in #260

^{Originally posted by irtaza-10x October 5, 2025}
Hi there, I recently started working with riscv asm and have been facing issues configuring the asm-lsp properly with my project.

Issues

Autocompletion and Reference

Pseudo Instructions

The Autocompletion for RISC-V pseudo-instructions does not seem to work. I tried to print reference for the la command but it threw the following error. A problem is also observed with macro completion and definition, the LSP error with id=46 when trying to print macro reference.

However running it on a RISC-V base command displays the desired result.

ABI Register Names

The LSP only seems to autocomplete and show definition of registers using the x0-x31 format. Names such as zero or mcause do not generate a diagnostic error but cause issues when trying to see their reference.

Error Message Indentation

The diagnostic messages appear at a weird offset from the actual erroneous line

Goto Definitions

Using gd on the label .L_test_failed gives the following error. A similar error is thrown when trying to goto macro definition with id=45

Cannot open file

Even though I have specified my path = "src/" in .asm-lsp.toml, it gives me the following error message: Cannot open macro.S for reading, No such file or directory found. But when change the .include macro.S to .include src/macro.S is seems to work.

Environment

I have installed asm-lsp on Neovim using :Mason. It shows that that version 0.10.0 is installed. Using :LspInfo shows the following:

vim.lsp: Active Clients ~
- asm_lsp (id: 1)
  - Version: ? (no serverInfo.version response)
  - Root directory: <PATH_TO_CURRENT_DIR>
  - Command: { "asm-lsp" }
  - Settings: {}
  - Attached buffers: 

My .asm-lsp.toml generated using the asm-lsp gen-config for the project is as follows:

[[project]]
path = "src"
version = "0.10.0"
assembler = "gas"
instruction_set = "riscv"

[project.opts]
compiler = "riscv64-unknown-elf-gcc"
compile_flags_txt = [
    '"-T riscv.ld"',
    "-nostdlib",
    "-march=rv32im_zicsr",
    "-mabi=ilp32",
]
diagnostics = true
default_diagnostics = false

The following is my directory structure based on the specification I have to work with:

.
├── Makefile
├── README.md
└── src
    ├── lib.s
    ├── macro.s
    ├── main.s
    ├── regs.s
    ├── riscv.ld
    ├── startup.s
    ├── syscalls.s
    └── trap.s

My git directory is 2 stages above the projects root directory. I did try to do git init in my current project directory but the above issues still persist.

Let me know if any additional information such as the :LspLog or my global .asm-lsp.toml is required.

Update: I have also added a compile_commands.json using bear -- riscv64-unknown-elf-gcc -T src/riscv.ld -nostdlib -march=rv32im_zicsr -mabi-ilp32 src/* -o build/main. The contents of the ./compile_commands.json are as follows:

[
  {
    "arguments": [
      "~/Desktop/Tests/RISCV64/riscv64-unknown-elf-toolchain/bin/riscv64-unknown-elf-gcc",
      "-c",
      "-mabi=ilp32",
      "-march=rv32im_zicsr",
      "-o",
      "build/main",
      "src/lib.S"
    ],
    "directory": "~/Desktop/Tests/current_dir",
    "file": "~/Desktop/Tests/current_dir/src/lib.S",
    "output": "~/Desktop/Tests/current_dir/build/main"
  },
  {
    "arguments": [
      "~/Desktop/Tests/RISCV64/riscv64-unknown-elf-toolchain/bin/riscv64-unknown-elf-gcc",
      "-c",
      "-mabi=ilp32",
      "-march=rv32im_zicsr",
      "-o",
      "build/main",
      "src/macro.S"
    ],
    "directory": "~/Desktop/Tests/current_dir",
    "file": "~/Desktop/Tests/current_dir/src/macro.S",
    "output": "~/Desktop/Tests/current_dir/build/main"
  },
  {
    "arguments": [
      "~/Desktop/Tests/RISCV64/riscv64-unknown-elf-toolchain/bin/riscv64-unknown-elf-gcc",
      "-c",
      "-mabi=ilp32",
      "-march=rv32im_zicsr",
      "-o",
      "build/main",
      "src/main.S"
    ],
    "directory": "~/Desktop/Tests/current_dir",
    "file": "~/Desktop/Tests/current_dir/src/main.S",
    "output": "~/Desktop/Tests/current_dir/build/main"
  },
  {
    "arguments": [
      "~/Desktop/Tests/RISCV64/riscv64-unknown-elf-toolchain/bin/riscv64-unknown-elf-gcc",
      "-c",
      "-mabi=ilp32",
      "-march=rv32im_zicsr",
      "-o",
      "build/main",
      "src/regs.S"
    ],
    "directory": "~/Desktop/Tests/current_dir",
    "file": "~/Desktop/Tests/current_dir/src/regs.S",
    "output": "~/Desktop/Tests/current_dir/build/main"
  },
  {
    "arguments": [
      "~/Desktop/Tests/RISCV64/riscv64-unknown-elf-toolchain/bin/riscv64-unknown-elf-gcc",
      "-c",
      "-mabi=ilp32",
      "-march=rv32im_zicsr",
      "-o",
      "build/main",
      "src/startup.S"
    ],
    "directory": "~/Desktop/Tests/current_dir",
    "file": "~/Desktop/Tests/current_dir/src/startup.S",
    "output": "~/Desktop/Tests/current_dir/build/main"
  },
  {
    "arguments": [
      "~/Desktop/Tests/RISCV64/riscv64-unknown-elf-toolchain/bin/riscv64-unknown-elf-gcc",
      "-c",
      "-mabi=ilp32",
      "-march=rv32im_zicsr",
      "-o",
      "build/main",
      "src/syscalls.S"
    ],
    "directory": "~/Desktop/Tests/current_dir",
    "file": "~/Desktop/Tests/current_dir/src/syscalls.S",
    "output": "~/Desktop/Tests/current_dir/build/main"
  },
  {
    "arguments": [
      "~/Desktop/Tests/RISCV64/riscv64-unknown-elf-toolchain/bin/riscv64-unknown-elf-gcc",
      "-c",
      "-mabi=ilp32",
      "-march=rv32im_zicsr",
      "-o",
      "build/main",
      "src/trap.S"
    ],
    "directory": "~/Desktop/Tests/current_dir",
    "file": "~/Desktop/Tests/current_dir/src/trap.S",
    "output": "~/Desktop/Tests/current_dir/build/main"
  }
]

```</div>