I have not used a texture in the past ten years, so cannot provide an example off the top of my head.
If I recall correctly, the quoted text refers to situations where a texture uses something like uchar4 texels representing four byte-wide channels (e.g. RGBA) , and the specified texturing mode converts each channel to a float normalized to [0, 1]. In such a case, each such float value would then be delivered to a separate 32-bit GPU register.