This code uses subb instead of cmpb to compare chars. When they are
not equal, the function's return value is computed by sign extending
the difference. The basic idea was contributed by Hiroshi Horitomo
<horimoto@cs-aoi.cs.sist.ac.jp> in PR #3223, but his implementation
used additional instructions to compute the return value.
Also, the series of insns used to compare one pair of characters has
been unrolled 4 times. This helps the 680[23]0, where the cost of a
taken branch is significantly more than that of a not-taken branch.
faster) byte-displacement form of the instruction if the offset will
fit. This happens to be all occurances in this case, so I could have
used bCCs. However, a quick survey of the rest of NetBSD's m68k code
showed that jCC was used in similar cases. I did the same to be
consistant.
jtc