Add Win64 code generation support

.github/workflows/TestingCI.yml

@@ -20,3 +20,22 @@ jobs:
         run: cargo test --release --verbose
       - name: Run fmt check
         run: cargo fmt --all -- --check
+
+  windows-native:
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup MSVC
+        uses: ilammy/msvc-dev-cmd@v1
+        with:
+          arch: x64
+      - name: Install LLVM/Clang
+        run: choco install llvm -y
+      - name: Add LLVM to PATH
+        run: echo "C:\Program Files\LLVM\bin" >> $env:GITHUB_PATH
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+      - name: Build
+        run: cargo build --release --verbose
+      - name: Run tests
+        run: cargo test --release --verbose

Cargo.toml

@@ -13,6 +13,9 @@ keywords = ["basic", "compiler", "x86-64", "retro", "programming-language"]
 categories = ["compilers", "command-line-utilities", "development-tools"]
 rust-version = "1.85"
 
+[features]
+default = []
+
 [dependencies]
 clap = { version = "4", features = ["derive"] }
 

src/abi.rs

@@ -0,0 +1,62 @@
+//! ABI abstraction layer for x86-64 calling conventions
+//!
+//! Provides platform-specific constants for System V AMD64 (Linux, macOS, BSD)
+//! and Win64 (Windows) ABIs.
+
+// Copyright (c) 2025-2026 Jeff Garzik
+// SPDX-License-Identifier: MIT
+
+/// Calling convention abstraction for x86-64
+pub trait Abi {
+    /// Integer/pointer argument registers (in order)
+    const INT_ARG_REGS: &'static [&'static str];
+
+    /// Symbol prefix for external symbols ("_" on macOS, "" elsewhere)
+    const SYMBOL_PREFIX: &'static str;
+}
+
+/// System V AMD64 ABI (Linux, macOS, BSD)
+pub struct SysV64;
+
+impl Abi for SysV64 {
+    const INT_ARG_REGS: &'static [&'static str] = &["rdi", "rsi", "rdx", "rcx", "r8", "r9"];
+
+    #[cfg(target_os = "macos")]
+    const SYMBOL_PREFIX: &'static str = "_";
+    #[cfg(not(target_os = "macos"))]
+    const SYMBOL_PREFIX: &'static str = "";
+}
+
+/// Windows x64 ABI
+#[cfg(any(windows, test))]
+pub struct Win64;
+
+#[cfg(any(windows, test))]
+impl Abi for Win64 {
+    const INT_ARG_REGS: &'static [&'static str] = &["rcx", "rdx", "r8", "r9"];
+    const SYMBOL_PREFIX: &'static str = "";
+}
+
+/// Type alias for the current platform's ABI
+#[cfg(windows)]
+pub type PlatformAbi = Win64;
+
+#[cfg(not(windows))]
+pub type PlatformAbi = SysV64;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_sysv64_int_regs() {
+        assert_eq!(SysV64::INT_ARG_REGS.len(), 6);
+        assert_eq!(SysV64::INT_ARG_REGS[0], "rdi");
+    }
+
+    #[test]
+    fn test_win64_int_regs() {
+        assert_eq!(Win64::INT_ARG_REGS.len(), 4);
+        assert_eq!(Win64::INT_ARG_REGS[0], "rcx");
+    }
+}