fasmi 1.5.3

Fasmi is a F# to Jitted ASM / IL disassembler as a dotnet tool

Getting Started

Install fasmi as a global dotnet tool

dotnet tool install fasmi -g

or as a dotnet local tool

dotnet new tool-manifest
dotnet tool install fasmi

Quickstart

Create a demo.fsx F# interactive script:

let inc x = x+1

run fasmi:

dotnet fasmi ./demo.fsx

and open the generated demo.asm file:

Demo.inc(Int32)
L0000: lea eax, [rcx+1]
L0003: ret

Watch mode

run fasmi in watch mode:

dotnet fasmi ./demo.fsx -w

Open the demo.fsx and demo.asm files side by side in your favorite editor, make changes to demo.fsx and save. The demo.asm file is updated on the fly.

Usage

Usage: [options] <source>
Arguments:
    <source>                      The source fsx or dotnet assembly file

Options:
    --watch, -w                   Run in watch mode
    --console, -c                 Output to console
    --output, -o <output-path>    Specify the output file
    --hex, -x                     Show instruction opcodes
    --platform, -p x64|x86        Specity the platform for disassembly (x64/x86)
    --language, -l asm|il         specify the output language

Input

The input can be a fsx F# script file or any dotnet .dll assemlby file. F# scripts are compiled for net 5.0.

Using a dotnet assembly as an input, you can use fasmi on any dotnet language.

Console

With the -c flag, the result is output to console rather than in a file.

Output

Use the -o flag to specifie the target file path and name.

Watch

The -w flag runs fasmi in watch mode. The file is recompiled and disassembled automatically when saved.

Platform

Use the -p flag to force x64 or x86 platform for disassembly.

Language

Specify the target language with the -l flag:

• asm : disassemble the jit output as a x86/x86 .asm file
• il : disassemble the output as a MSIL .il file

Completion

Thanks to Fargo, fasmi can provide command line completion for powershell, fish and bash.

To get the installation script:

# for powershell
fasmi completion powershell
# for bash
fasmi completion bash
# for fish
fasmi completion fish

Copy the code in your profile file.

For other shells it is possible to adapt the code.

Acknowledgment

This tool is based on Andrey Shchekin code for https://sharplab.io/.

Contributing

Help and feedback is always welcome and pull requests get accepted.

• First open an issue to discuss your changes
• After your change has been formally approved please submit your PR against the develop branch
• Please follow the code convention by examining existing code
• Add/modify the README.md as required
• Add/modify unit tests as required
• Please document your changes in the upcoming release notes in RELEASE_NOTES.md
• PRs can only be approved and merged when all checks succeed (builds on Windows, MacOs and Linux)