slop n.
1. A one-sided fudge
factor, that is, an allowance for error but in only one
of two directions. For example, if you need a piece of wire 10
feet long and have to guess when you cut it, you make very sure
to cut it too long, by a large amount if necessary, rather than
too short by even a little bit, because you can always cut off
the slop but you can't paste it back on again. When discrete
quantities are involved, slop is often introduced to avoid the
possibility of being on the losing side of a fencepost error. 2. The percentage
of `extra' code generated by a compiler over the size of
equivalent assembler code produced by hand-hacking; i.e., the space (or maybe
time) you lose because you didn't do it yourself. This number is
often used as a measure of the goodness of a compiler; slop below
5% is very good, and 10% is usually acceptable. With modern
compiler technology, esp. on RISC machines, the compiler's slop
may actually be negative; that is, humans may be unable
to generate code as good. This is one of the reasons assembler
programming is no longer common.