Change 3 functions to be #defines of others

Change 3 functions to be #defines of others

I made these separate functions because I thought it would make faster
code, but I realized that modern compilers should be able to optimize
the more general functions into the same code as the ones removed by
this commit, given that the parameters are known to be 0 at compile
time.

It's easier to maintain one version of a function than two, so this
commit favors that.