Will's investigations show that all but a few of the C functions duplicated in SRFI 144 aren't any faster than his Scheme equivalents.  I'm concerned that this will not be true on compile-to-C systems, where systems may be smart enough to output flsin, say, as a call to sin(), which is then open-coded by the C compiler.  Since Larceny calls C sin via its FFI, which bypasses such open-coding, this benefit is lost.