History

Intubun 8e8fada32f Add WASM entry point and Emscripten build wiring The pieces that make Magic actually buildable as a WASM library. * magic/magicWasm.c — new headless entry point exporting four functions used by the JS wrapper: - magic_wasm_init() idempotent initialisation - magic_wasm_run_command(s) dispatch one Magic command - magic_wasm_source_file(p) execute a script from the VFS - magic_wasm_update() drive a display-update cycle Sets CAD_ROOT=/ if unset, so embedded technology files under /magic/sys/ resolve correctly. Centers the command point inside GrScreenRect so commands route to the layout window client rather than the border/window-management client. * utils/main.c, utils/main.h — split magicMain() into magicMainInit() + the dispatch loop. magicMainInit is idempotent (a static flag guards against re-initialisation) so JS callers can call any of the four wasm entry points first without sequencing. * magic/Makefile — adds the WASM link target, gated by MAKE_WASM=1 set from toolchains/emscripten/defs.mak. Conditionally compiles magicWasm.c into the main binary, links to magic.js and runs post-build.sh on the result. * toolchains/emscripten/defs.mak — Emscripten linker flags (WASM=1, MODULARIZE, EXPORT_ES6, ALLOW_MEMORY_GROWTH, INITIAL_MEMORY=32M, STACK_SIZE=5M), the four EXPORTED_FUNCTIONS, and the embed-file bindings for the technology files under /magic/sys/. * toolchains/emscripten/post-build.sh — patches Emscripten's ESM output so it works in pure Node.js ESM: aliases require() through createRequire, injects __filename / __dirname shims, and resyncs the ___emscripten_embedded_file_data constant from the wasm global section if Emscripten emitted a stale value. Idempotent and pinned to emsdk 3.1.56 (see WARNING in the header). * toolchains/emscripten/README.md — full build documentation: quick-start via npm/build.sh, manual build, list of embedded files, exported C API, JavaScript usage example, and notes on CAD_ROOT, DISPLAY_SUSPEND, and the signal-API stubs. * .gitignore — adds the WASM artefacts (magic.js, magic.wasm, magic.symbols), tightens the editor/OS cruft list, and keeps toolchains/emscripten/defs.mak tracked despite the `defs.mak` ignore rule.		2026-05-11 14:20:47 -04:00
..
README.md	Add WASM entry point and Emscripten build wiring	2026-05-11 14:20:47 -04:00
defs.mak	Add WASM entry point and Emscripten build wiring	2026-05-11 14:20:47 -04:00
post-build.sh	Add WASM entry point and Emscripten build wiring	2026-05-11 14:20:47 -04:00

README.md

Magic VLSI — Headless WASM Build

This toolchain builds Magic as a headless WebAssembly module using Emscripten. X11, Tk, OpenGL, and readline are all disabled. The resulting magic.js / magic.wasm pair can be loaded in Node.js, a browser, or a Web Worker.

Quick start (npm package)

The easiest way to build and use the WASM module is through the npm package:

# Build magic.js + magic.wasm and copy them into npm/
bash npm/build.sh

# Run the test suite (extract, GDS, DRC, CIF)
npm --prefix npm test

See npm/examples/ for usage examples.

Manual build

Prerequisites: an activated emsdk checkout (emcc, emar, emranlib on PATH), plus standard make and gcc.

# 1. Configure for Emscripten
CFLAGS="--std=c17 -D_DEFAULT_SOURCE=1 -DEMSCRIPTEN=1 -g" \
  emconfigure ./configure \
    --without-cairo --without-opengl --without-x --without-tk --without-tcl \
    --disable-readline --disable-compression \
    --host=asmjs-unknown-emscripten \
    --target=asmjs-unknown-emscripten

# 2. Append the Emscripten-specific make settings
cat toolchains/emscripten/defs.mak >> defs.mak

# 3. Build
emmake make depend
emmake make -j$(nproc) modules libs
emmake make techs
emmake make mains

The outputs are magic/magic.js and magic/magic.wasm.

Embedded files

The following runtime files are baked directly into the WASM binary via Emscripten's --embed-file mechanism and are available at startup without any host filesystem access:

Host path	VFS path
`scmos/`	`/magic/sys/current/`
`windows/windows7.glyphs`	`/magic/sys/windows7.glyphs`
`windows/windows7.glyphs`	`/magic/sys/bw.glyphs`

To embed a custom technology file, add an --embed-file entry to TOP_EXTRA_LIBS in defs.mak.

Exported C API

The WASM module exports four functions:

Function	Description
`magic_wasm_init()`	Initialize Magic (idempotent — safe to call multiple times). Returns 0 on success.
`magic_wasm_run_command(const char *cmd)`	Dispatch one Magic command. Calls `magic_wasm_init()` automatically if needed. Returns 0 on success.
`magic_wasm_source_file(const char *path)`	Read and execute a command file from the virtual filesystem.
`magic_wasm_update()`	Drive a display-update cycle. No-op in headless builds (null display suspends all redraws).

JavaScript usage

import createMagic from 'magic-vlsi-wasm';

const { runCommand, FS } = await createMagic();

// Write a layout file into the virtual filesystem
FS.writeFile('/work/inv.mag', layoutBytes);

// Run Magic commands
runCommand('tech load sky130A');
runCommand('load /work/inv');
runCommand('gds write /work/inv');

// Read the result back out
const gdsBytes = FS.readFile('/work/inv.gds');

Notes

CAD_ROOT is automatically set to / so that embedded system files are resolved under /magic/sys/.
The null display driver (-d null) sets GrDisplayStatus = DISPLAY_SUSPEND, which causes WindUpdate to return immediately without invoking any display callbacks. This is what makes the WASM build safe to run without a screen.
All POSIX signal/timer APIs (setitimer, SIGALRM, fcntl) are compiled out under __EMSCRIPTEN__; the display progress timer becomes a no-op.