瀏覽代碼
* is_signed() only returns true for orddef's whose low value is < 0
(and not for all s8bit..s64bit types, since subrange types may
be marked like that but not have a lower bound < 0).
This is needed for bitpacking negative values, because e.g.
both 0..7 and -3..3 can be stored in 3 bits, but 0..7 must be
zero-extended when extracted (so must be unsigned) and -3..3 must
be sign-extended when extracted (so must be considered signed)
git-svn-id: trunk@6682 -