More documentation for obscure functions

I was going to batch up a bunch of these, like last time, but I ran into something I couldn't figure out; perhaps it's obvious to you, or someone else.

In particular, I don't understand this block:

```C
            case 1:  // eax == 1: processor info and feature flags
            default:
                regs[0] = (5 << 8) | (4 << 4) | 3; // family | model | stepping
                regs[3] = 8 << 8; // ???????  
                regs[1] = 0;
                regs[2] = (1 << 4); // rdtsc support
                break;
```

If I'm reading it correctly, the line labeled `???????` sets a bit that would, on a modern processor, indicate the CLFLUSH line size. AFAIK, that wouldn't apply to a 486. Did that bit used to mean something else in the distant past?