SASS Assembler

A specialized assembler for NVIDIA's Shader Assembly (SASS) language, targeting native GPU machine code generation.

🏛️ Architecture

graph TB
    subgraph "SASS Compilation Flow"
        A[SASS Instructions] --> B[Kernel Builder]
        B --> C[Instruction Encoder]
        C --> D[ELF Encapsulation]
        D --> E[CUDA Binary (.cubin)]
        
        subgraph "Instruction Groups"
            F[Floating Point (FADD/FMUL)]
            G[Integer Ops (IMAD/ISETP)]
            H[Memory Ops (LDG/STG)]
            I[Control Flow (BRA/EXIT)]
        end
        
        B --> F
        B --> G
        B --> H
        B --> I
    end

🚀 Features

Core Capabilities

• Native GPU Encoding: Direct encoding of SASS instructions into their binary representation for NVIDIA GPUs.
• Kernel Management: Organizes instructions into valid GPU kernels with appropriate ELF section headers (.text, .nv_fatbin).
• Instruction Support: Covers a wide range of SASS instructions including floating-point arithmetic (FADD, FMUL), integer operations, and global memory access (LDG, STG).

Advanced Features

• ELF/CUBIN Generation: Automatically wraps generated machine code into standard ELF containers compatible with the CUDA driver API.
• Disassembly View: (🚧) Provides tools to disassemble binary kernels back into human-readable SASS text.
• Control Flow: Supports basic control flow instructions and termination codes (EXIT, NOP).

💻 Usage

Generating a Simple CUDA Kernel

The following example shows how to create a basic SASS kernel and write it to a binary file.

use sass_assembler::{SassProgram, SassWriter, instructions::SassInstruction};
use std::fs;

fn main() {
    // 1. Define SASS instructions
    let instructions = vec![
        SassInstruction::FAdd { dst: "R0".into(), src0: "R1".into(), src1: "R2".into() },
        SassInstruction::Exit,
    ];

    // 2. Build program structure
    let program = SassProgram::new("my_kernel", instructions);

    // 3. Write to binary (simulated ELF)
    let writer = SassWriter::new();
    let binary = writer.write(&program).expect("Failed to generate SASS binary");
    
    fs::write("kernel.cubin", binary).unwrap();
}

🛠️ Support Status

Legend: ✅ Supported, 🚧 In Progress, ❌ Not Supported

🔗 Relations

• gaia-types: Utilizes basic error handling and binary types for instruction encoding.
• gaia-assembler: Serves as the native NVIDIA GPU backend for the Gaia project, allowing high-performance offloading of compute tasks.