@bnoordhuis I thought it was `memcpy(<dest>,<orig>, <size>)`, so I'm copying from `ptr` to and then swizzling `&val`. The implementation your discussing is used in `WriteGeneric`. Also if you're talking about returning `Undefined()`, that's also done in `WriteGeneric`. Or do you mean return `Undefined()` for out of range values?

Can you elaborate on a value that matches a description of `*(uint32_t*)&val & 0x7fb0 == 0x7fb0`? I wrote the following to come up with a few numbers, but don't know if it's what you were talking about:

```javascript
var buf = new Buffer(4);
var tmp, i;
for (i = 0; i < 1e8; i++)
	if ((i & 0x7fb0) == 0x7fb0) {
		buf.writeFloatBE(i, 0);
		if (buf.readFloatBE(0) !== i)
		// also tried the following, but nothing was returned
		//if (isNaN(buf.readFloatBE(0)))
			console.log(i);
	}
```

One of the values that popped out was `33554425`. v0.8.16 returned `33554426`, while this implementation returned `33554424`. So each is off by 1, but in the different direction.

What this has alerted me to is the fact that the limits test in `WriteGeneric` is incorrect, and I'll probably use the implementation we discussed earlier.