On Tue, Jun 15, 2010 at 2:13 PM, Joern Rennecke <amyl...@spamcop.net> wrote: > > It is using whatever floating point format the target has. > If you don't have hardware floating point support, then you get to > choose the format when you design your ABI.
Yes, my target has no fp. Thanks! This is not mine to decide if I just use a gcc floating point library like fp-bit and soft-fp, right? > There are two C implementations of IEEE software floating point in the > GCC runtime: > - fp-bit.c, which is fairly old and slow, but requires little work to use > if longlong.h supports your processor (which is also needed for GNU mp). > It only has round-to-nearest, no signals, but subnormals work except for > one rounding issue with division. > - soft-fp. This is supposed to be a bit faster, but you need to define > various primitives. The default configuration is similar in features > to fp-bit.c, but you can customize it for support of signals ('exceptions') > and other rounding modes. > I started using fp-bit.c since I read somewhere (I wonder where I read this) that soft-fp won't work if BITS_PER_UNIT != 8. Is there any documentation explaining the implementation of floating points in fp-bit.c and soft-fp.c? Mainly their internal representation. -- PMatos