assembly-riscv

assembly-riscv is a skill for Codex from OutlineDriven/outline-driven-development. It costs 46 tokens per session (1,849 once invoked), scanned A, original, Apache-2.0.

A guide to reading and writing RISC-V assembly, the low-level instructions used by RISC-V processors. It also explains how C code, registers, calling conventions, instruction extensions, and QEMU-based debugging fit together.

In plain words
What is it for?
Use it to write inline assembly in C, understand compiler output, choose RV32 or RV64 extensions, and debug RISC-V code with QEMU and GDB.
Why use it?
It helps prevent incorrect register use and instruction choices when working close to RISC-V hardware.

Skill for Codex

Written for Codex: agents/openai.yaml present.

Good fit Use it to write inline assembly in C, understand compiler output, choose RV32 or RV64 extensions, and debug RISC-V code with QEMU and GDB.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/outlinedriven/outline-driven-development/assembly-riscv
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add OutlineDriven/outline-driven-development --skill assembly-riscv
Clone the repo
git clone --depth 1 https://github.com/OutlineDriven/outline-driven-development

Made for: Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for assembly-riscv

README.md
[![agentmods](https://agentmods.dev/badge/skills/outlinedriven/outline-driven-development/assembly-riscv.svg)](https://agentmods.dev/skills/outlinedriven/outline-driven-development/assembly-riscv)
Your own site
<a href="https://agentmods.dev/skills/outlinedriven/outline-driven-development/assembly-riscv"><img src="https://agentmods.dev/badge/skills/outlinedriven/outline-driven-development/assembly-riscv.svg" alt="Measured on agentmods" height="20"></a>
Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,849 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00046 $0.01849
Opus 5 $0.00023 $0.00924
Sonnet 5 $0.00009 $0.00370
Haiku 4.5 $0.00005 $0.00185

Measured yesterday against content hash 3467ec4fc192, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

assembly-riscv scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.devin/skills/assembly-riscv/SKILL.md · 129 lines

How it starts

The opening of the file, as written. The whole thing — 129 lines — stays where its author put it; the contents beside it link to each section on GitHub.

RISC-V assembly

RISC-V is a small load-store ISA grown through named extensions. This skill covers user-mode RV32 and RV64 assembly, the psABI register contract, and the QEMU loop.

Contract

Field Bound contract
Trigger The task writes inline asm or assembly for RV32 or RV64, decodes ABI register names, names an ISA extension string, enables compressed instructions, or debugs RISC-V under QEMU with GDB.
Authority Read-only. The skill explains and drafts; edits land through the normal coding path. No remote mutation.
Side effect None.
Done The drafted assembly assembles for the named base ISA and extensions, or the compiler output under discussion is explained register by register.

Inputs

  • The C or C++ source, assembly fragment, or compiler output: required.
  • The base ISA and extensions: required. The -march string such as rv64gc, written IMAFDC in ISA order.
  • The execution environment: required. QEMU virt for user or system work, hardware otherwise.

Procedure

  1. Map registers by role. The ABI names are what disassembly and assembly listings show. Done when: every register in the fragment is classified.
Register ABI name Role
x0 zero Hardwired zero, writes are discarded
x1 ra Return address
x2 sp Stack pointer
x3 gp Global pointer
x4 tp Thread pointer
x5 to x7, x28 to x31 t0 to t6 Temporaries, caller saved
x8 s0/fp Frame pointer or saved register, callee saved
x9, x18 to x27 s1, s2 to s11 Saved registers, callee saved
x10 to x17 a0 to a7 Arguments and return values, caller saved
f0 to f7, f28 to f31 ft0 to ft11 FP temporaries, caller saved
f8 to f9, f18 to f27 fs0 to fs11 FP saved, callee saved
f10 to f17 fa0 to fa7 FP arguments and returns, caller saved
  1. Write the calling convention into the code. Args go in a0 to a7, extra args on the stack, return value in a0. Save callee-saved registers before use and restore them before return. Done when: any s register used is saved and restored.

Read the full file on GitHub · 129 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 129 lines · 46 tokens per session scan A 3467ec4fc192

Subscribe to this mod's changes

assembly-riscv is a skill published in the GitHub repository OutlineDriven/outline-driven-development (52 stars, last pushed 2d ago), licensed Apache-2.0. It adds 46 tokens to every session and 1,849 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-06.

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