Table of Contents

Cosmos.Asm.Build compiles handwritten assembly sources into object files that are linked with the NativeAOT output.

Flow chart

flowchart TD
    A[GetYasm] --> B[FindSourceFilesForYasm]
    B --> C[BuildYasm]
    C --> D[.obj files under cosmos/asm]

Parameters

Name Description Default
YasmPath Full path to the yasm executable. Auto-detected by GetYasm if not set. Unix: /usr/bin/yasm; Windows: resolved via where yasm
AsmSearchPath One or more directories to scan (non-recursive) for *.asm. none
AsmFiles Explicit list of *.asm files to compile (added to scan results). none
AsmOutputPath Directory for compiled object files. $(IntermediateOutputPath)/cosmos/asm/

Notes:

  • On Unix, YasmPath also defaults from props if empty; on all platforms GetYasm attempts to locate yasm on PATH.
  • When RuntimeIdentifier is set (e.g., linux-x64), FindSourceFilesForYasm will prefer an architecture subfolder if present (e.g., <searchDir>/x64/).

Tasks

Task Description Depends On
GetYasm Resolves YasmPath using which (Unix) or where (Windows). none
FindSourceFilesForYasm Cleans inputs, applies arch overrides, and discovers *.asm under AsmSearchPath. Build
BuildYasm Invokes YasmBuildTask for each file with -felf64, writing to AsmOutputPath. FindSourceFilesForYasm; GetYasm
CleanYasm Removes $(IntermediateOutputPath)/cosmos/asm/. Clean

Detailed Workflow

  1. GetYasm attempts to set YasmPath from the system (which yasm or where yasm). You can override YasmPath in your project.
  2. FindSourceFilesForYasm:
    • Removes any nonexistent entries from AsmSearchPath and AsmFiles (emits warnings).
    • If RuntimeIdentifier is set, replaces any AsmSearchPath that contains a matching arch subfolder with that subfolder (e.g., x64).
    • Builds a non-recursive search pattern %(AsmSearchPath.FullPath)/*.asm and adds results to AsmFiles (deduplicated).
  3. BuildYasm calls the YasmBuildTask for each file:
    • Computes a SHA1 of the source and emits <name>-<sha1>.obj into AsmOutputPath.
    • Executes yasm -felf64 -o <output.obj> <input.asm>.
  4. CleanYasm deletes the cosmos/asm intermediate folder during Clean.

Outputs

  • Object files in $(IntermediateOutputPath)/cosmos/asm/ named as <sourceName>-<sha1>.obj where <sha1> is the content hash of the source. This guarantees deterministic, cache-friendly names across builds.
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