In more "pointless things to do with PHP", I've been toying around with Assembly for GameBoy (https://gbdev.io/gb-asm-tutorial/part1/assembly.html) ... and testing out compiling PHP code into a gb file.
RGBDS has most of the constants that are needed. And as long as any variables are unsigned int and less than 255... we're golden.
`$x = 123` is basically `ld a, 123 / ld [$c000] a`
I'm able to bruteforce the compiler, being very careful with the PHP. I may write this up.