[phire]

The other major difference is that golf.horse requires the payload to be valid uft8 javascript, which means your binary blobs are essentially limited to base64 encoded strings. You might manage slightly better, but I suspect the limit is somewhere around 6.5bits per byte.

On the gameboy, you have the advantage of being able to use the full 8 bits per byte.

[lifthrasiir]

The possible number of x-byte-long valid UTF-8 strings is defined with the following recurrence relation:

    f(-x) = 0
    f(0) = 1
    f(x) = 0x80 * f(x-1) + 0x780 * f(x-2) + 0xf400 * f(x-3) + 0x100000 * f(x-4)

(Replace 0x80 with 0x7c to account for ES6 template literals.) The characteristic polynomial for this recurrence has a positive root of 144.61 (or 141.12 for literals). This means that you can actually put quite more than 7 bits per byte in a valid JS code, provided that your decoder is negligibly small enough. Indeed, there exists an encoding that allows exactly 7 bits per byte by using two-byte-long UTF-8 sequence as an escape code [1].

[1] http://blog.kevinalbs.com/base122

[phire]

Huh. Javascript is significantly more accepting of non-printing characters in it's strings than I was expecting. I guess I should have known better.