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RASM

x86_64 assembler with Intel syntax

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RASM (Red Assembler) — x86_64 assembler with Intel syntax.

Features and Benefits

• Cross-platform: ELF64 for Linux, Mach-O for macOS, and PE32+ & COFF64 for Windows.

• Native emitter: RASM does not require an external linker to create executable files.

  Most popular assemblers generate object files and require a separate linking step:

  • NASM → ld / lld / link.exe
  • GAS → ld / lld / link.exe
  • MASM → link.exe
  • YASM → ld / lld / link.exe

  RASM performs the entire process on its own.

• JIT compilation: RASM has JIT compilation, which means that you can run your code without compiling it into an executable file.

• Library: You can connect librasm to your Cargo.toml, and use RASM through simple function calls!
• Minimum dependencies: The entire workspace uses only 3 external dependencies.
• Errors and Diagnostics: Errors look in rustc/clang style.

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Sample program

Let's write a simple program that outputs "Hello, world!" to the terminal.

On Windows

Save this code to main.s:

.import kernel32.dll GetStdHandle
.import kernel32.dll WriteFile

.data
msg:
    .ascii "Hello, world!\r\n"
written:
    dd 0

.text
_start:
    sub rsp, 40

    mov rcx, -11
    call GetStdHandle

    mov rcx, rax
    lea rdx, [rip + msg]
    mov r8, 15
    lea r9, [rip + written]
    mov qword [rsp + 32], 0
    call WriteFile

    add rsp, 40
    mov rax, 0
    ret

Next, run the program:

# Using the JIT compiler:
rasm run main.s

# Using the AOT compiler:
rasm build main.s

# Then run the compiled file:
./main.exe

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On Linux

Save the code below to a file named main.s:

_start:
    jmp print

msg:
    .ascii "Hello, world!\n"

print:
    mov rax, 1
    mov rdi, 1
    lea rsi, [rip + msg]
    mov rdx, 14
    syscall

    mov rax, 60
    xor rdi, rdi
    syscall

Next, run the program:

# Using the JIT compiler:
rasm run main.s

# Using the AOT compiler:
rasm build main.s

# Then run the compiled file:
./main

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Supported output formats

Supported formats for executable files.

Format	Platform
ELF64	Linux
Mach-O	macOS
PE32+	Windows

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Comparison

Opportunity	RASM	NASM	FASM	MASM
Intel syntax	✅	✅	✅	✅
Direct generation of ELF64 executable files	✅	❌	✅	❌
Direct generation of PE32+ executable files	✅	❌	✅	❌
Built-in emitter	✅	❌	✅	❌
JIT execution	✅	❌	❌	❌
The official library API	✅	❌	✅	❌

The main difference between RASM and NASM, FASM and MASM is built-in emitter, JIT execution and the ability to use as libraries.

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Project status

The development of RASM is actively continuing.

Quick start

Download Options RASM:

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1. Via Github Releases (recommended)

Download the latest RASM version for your OS from Github Releases.

If you have Linux/macOS, make the file executable:

chmod +x rasm
./rasm -v

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2. Build from the source code (need rustc & cargo 1.96.0)

1. Clone the repository (you need git) and go to the working directory

   git clone https://github.com/dev-er1/rasm.git
   cd rasm

2. Compile the workspace and remove the RASM from the target

   cargo build --release
   
   # Here you need to get the binary to your current directory so that the following command will work for you.
   ./rasm -v

3. Add to the PATH (optional)

   So that you can run RASM from any folder by simply writing rasm, add the binary file to the environment variables of your OS:

   • If you have Linux/macOS:

     Add a line to your configuration file (for example, ~/.bashrc or ~/.zshrc):

     export PATH="$PATH:/path/to/folder/with/rasm"

   • For Windows:

     Run the command in PowerShell as an Administrator:

     [Environment]::SetEnvironmentVariable("Path", $env:Path + ";С:\path\to\rаѕm ", "User")

     (After that, restart the terminal)

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Documentation and other documents

• Documentation — documentation.
• Contributing — the rules of contributing.
• CoC — standards of behavior in the Issue/Discussions.
• Architecture — architecture documentation.
• Security policy — security policy.
• Changelog
• NOTICE — third-party attributions and license references.
• Third-Party Licenses — license texts of bundled dependencies.
• To Do list