You can definitely round a float to the nearest integer-represented-as-a-float by accessing its bits. It will work.

It will not be faster on a modern processor, though, because floating-point numbers live in their own registers, distinct from integer registers. Floating-point registers do not have bitwise operations, moving data to and from integer registers is comparatively expensive, but they have IEEE 754 arithmetic.

So the game is to do as much as possible with what instructions there are. One such instruction is for instance (for processors with SSE2) " cvttss2si %xmm0, %eax", to truncate a float in xmm0 to an int in eax. Intel provided an instruction for that because the C language defines the cast float -> int as a truncation.

The next blog post in the series will be about using IEEE 754 addition to avoid the round-trip through eax altogether.