Alyssa Rosenzweig

Photo of Alyssa I’m a graphics developer passionate about software freedom, leading the Panfrost and Asahi graphics drivers. I keep a blog (general feed, technical feed, archive). Outside of computing, I study mathematics at the University of Toronto as a Lester B. Pearson International Scholar. My résumé is available. My email is (key). Due to volume I cannot reply to all messages. 🇨🇦 🏳️‍🌈

Reverse-engineering the Mali G78

After a month of reverse-engineering, we’re excited to release documentation on the Valhall instruction set, available as a PDF. The findings are summarized in an XML architecture description for machine consumption. In tandem with the documentation, we’ve developed a Valhall assembler and disassembler as a reverse-engineering aid…

Dissecting the Apple M1 GPU, part IV

After beginning a compiler for the Apple M1 GPU, the next step is to develop a graphics driver exercising the compiler. Since the last post two weeks ago, I’ve begun a Gallium driver for the M1, implementing much of the OpenGL 2.1 and ES 2.0 specifications. With the compiler and driver together, we’re now able to run OpenGL workloads like glxgears and scenes from glmark2 on the M1 with an open source stack. We are passing about 75% of the OpenGL ES 2.0 tests in the drawElements Quality Program used to establish Khronos conformance. To top it off, the compiler and driver are now upstreamed in Mesa

Software freedom isn’t about licenses – it’s about power.

A restrictive end-user license agreement is one way a company can exert power over the user. When the free software movement was founded thirty years ago, these restrictive licenses were the primary user-hostile power dynamic, so permissive and copyleft licenses emerged as synonyms to software freedom. Licensing does matter; user autonomy is lost with subscription models, revocable licenses, binary-only software, and onerous legal clauses. Yet these issues pertinent to desktop software do not scratch the surface of today’s digital power dynamics…

Fun and Games with Exposure Notifications

Exposure Notifications is a protocol developed by Apple and Google for facilitating COVID-19 contact tracing on mobile phones by exchanging codes with nearby phones over Bluetooth, implemented within the Android and iOS operating systems, now available here in Toronto…

From Bifrost to Panfrost - deep dive into the first render

In Panfrost’s infancy, community members Connor Abbott and Lyude Paul largely reverse-engineered Bifrost and built a proof-of-concept shader dis/assembler. Meanwhile, I focused on the Midgard architecture (Mali T600+), building an OpenGL driver alongside developers like Collaboran Tomeu Vizoso…

The Federation Fallacy

Throughout the free software community, an unbridled aura of justified mistrust fills the air: mistrust of large corporations, mistrust of governments, and of course, mistrust of proprietary software. Each mistrust is connected by a critical thread: centralisation…

“Hollywood’s Secret Weapon: DRM”

A persuasive writing experiment (commentary)

Hilariously Fast Volume Computation with the Divergence Theorem

(No, there won’t be jokes.)