Let’s be honest, saying “just fix the page tables” is like telling someone they can fly if they “just rewrite gravity.”
Yes, on Apple Silicon, the hardware supports shared physical memory, and with enough “convincing”, you can rig up a contiguous virtual address space for both the CPU and GPU. Apple’s unified memory architecture makes that possible, but Apple’s APIs and memory managers don’t expose this easily or safely for a reason. You’re messing with MMU-level mappings on a tightly integrated system that treats memory as a first-class citizen of the security model.
Oh yes I programmed all the Amiga models, mostly in assembly level. I reprogrammed the ROMs. I also published a magazine on all the Commodore computers internals and build lots of hardware for these machines.
We had the parallel Inmos Transputer systems during the heyday of the Amiga, they where much better designed than any the custom Amiga chips.
Inmos was a disaster. No application ever shipped on one. EVER. It used a serial bus to resolve the problems that should have never been problems. Clearly you never wrote code for one. Each oslink couldn't reach more than 3 feet. What a disaster that entire architecture was.
I shipped 5 applications on an 800 Inmos Transputer supercomputer. Sold my parallel C compilers, macro Assembler. Also an OS, Macintosh Nubus interface card, Transputer graphics cards, a full paper copier and laserprinter. I know of dozens of successful products.
Hey don't shit on my retro alternative timeline nostalgia. We were all writing Lisp programs on 64 CPU Transputer systems with FPGA coprocessors, dynamically reconfigured in realtime with APL.
/s/LISP/Prolog and you've basically described the old "Fifth Generation" research project. Unfortunately it turns out that trying to parallelize Prolog is quite a nightmare, the language is really, really not built for it. So the whole thing was a dead-end in practice. Arguably we didn't have a real "fifth-gen" programming language prior to Rust, given how it manages to uniquely combine ease of writing parallel+concurrent code with bare-metal C like efficiency. (And Rust is now being used to parallelize database query, which comfortably addresses the actual requirement that Prolog had been intended for back then - performing "search" tasks on large and complex knowledge bases.)