chris@mimsy.umd.edu (Chris Torek) (02/16/90)
(My apologies for the extensive quoting: I trimmed as much as I thought reasonable.) In article <17910@rpp386.cactus.org> woody@rpp386.cactus.org (Woodrow Baker) suggests that ANSI C should have included: >>>>FIXED i.e. fixed point math. ... would deal with chars, ints, longs >>>>and quads. There would be an assumed binary point in the middle of the >>>>data... (`short' seems to be missing from the above list.) In article <1990Feb12.182343.14269@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) points out: >>>But *I* want the assumed binary point three bits from the right! :-) This >>>whole area is a massive swamp of conversion rules, overflow handling, etc. In article <1990Feb13.114041.4178@bath.ac.uk> exspes@bath.ac.uk (P E Smee) writes: >>PL/1 offered that. In years of PL/1 programming, I believe I only ever >>saw two or three programs (by anyone) that used it. ... [Things were] >>so baroque that it was actually usually easier to simply declare >>everything as 'fixed bin (n,0)' (effectively, int/long/short) and [do >>the work yourself]. This, of course, was Henry's point: fixed-point support is not nearly as simple as it first appears. In article <17950@rpp386.cactus.org> woody@rpp386.cactus.org (Woodrow Baker) writes: >People, missed my point, that fixed point does not require conversions. >A fixed int and an int are the same thing. i.e., they should substitue >for each other. It is merely where you have the binary point. Conversion >to and from float, fixed, and int are not a problem. fixed to float is >real easy, float to fixed is also easy. ... You cannot have it both ways: Either a fixed int and an int are the same thing---in which case, you do not need `fixed int' in the language, because it is just another word for `int'---or they are different. If they are different, it is an untested change to C and does not belong in the standard. If the fixed point you propose is simply an alias, all you need to do is typedef long fixedpoint; If the fixed point you propose comes with conversions, Henry's objection applies. `If you want PL/I, you know where to find it,' -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@cs.umd.edu Path: uunet!mimsy!chris