km38#@andrew.cmu.edu.UUCP (02/25/87)
I have access to two compilers, who behave completely differently. With the
following declaration,
type REAL is delta 0.01;
the first one accepts it, and the other one says
48 type REAL is delta 0.01;
.......................1
%ADAC-E-FIXTYPERANGE, (1) A fixed point type declaration requires a range
constraint
I think the second compiler is right in signaling an error, but what about
the first compiler? It is validated with ACVC 1.5.
Thanks,
--Magnus
Arpa: magnus@andrew.cmu.edu
UUCP: seismo!andrew.cmu.edu!magnusMendal@SIERRA.STANFORD.EDU (Geoff Mendal) (03/02/87)
All fixed point types must specify a range constraint, in addition to a "delta" accuracy. See ARM 3.5.9(3). Note that the range constraint is optional for fixed point SUBTYPES. The reason for requiring the range constraint on the fixed type definition is that the underlying model numbers are "computed" using both the delta accuracy and the range constraint. For a floating point type definition, model numbers are computed solely by the digits accuracy, hence the reason why a range constraint is not required for a floating point type definition. gom -------
GOODENOUGH@A.ISI.EDU (John B. Goodenough) (03/02/87)
The declaration type REAL is delta 0.01; should be rejected by a compiler. The ACVC tests for 1.9 have been greatly strengthened in the fixed point area, and should detect this deficiency. -------
keith@telesoft.UUCP (03/04/87)
> > type REAL is delta 0.01; > LRM 3.5.9:3 "If the fixed point constraint is used as a real type definition, then it must include a range constraint; ..." Obviously the first compiler (validated on 1.5) is incorrect. It is entirely possible that the 1.5 ACVC did not test this feature of the language. Our compiler produced the following: 2: type REAL is delta 0.01; ---------- >>> Range constraint required for fixed point type <3.5.9:6> LRM 3.5.9:6 starts "For a fixed point constraint that includes a range constraint..." Keith -- Keith Allan Shillington telesoft!keith@UCSD.ARPA 619/457-2700x388.ATT My opinions are mine. {ucbvax!sdcsvax,hp-sdd,bigbang}!telesoft!keith.UUCP