On Thu, Sep 05, 2002 at 04:54:09PM +0200, Maciej W. Rozycki wrote: > On Thu, 5 Sep 2002, Hartvig Ekner wrote: > > > I don't know the ultimate reasons why SGI choose ILP32 for n32, but one > > could certainly be portability. > > It depends on how you define "portability". While it might help some > broken software, it will hurt good one. > > > As defined, n32 provides all the benefits of 64-bit data (yes, you have > > to use long long to get to it), and 100% backward compatability with > > So you can't use long to keep a file position pointer (off_t is quite a > new invention) and have to go for long long, for example? Weird and > definitely doesn't help portability. > > > o32 sources that assume (sizeof(void *)) = sizeof(long), plus binary data > > Thay should be fixed, instead. Using "void *" as a data container > doesn't work in general and one who does so should be banished. And the > other way round, there is no problem -- if one keeps 32-bit pointers in > 64-bit longs, there is no bit loss. > > > file compatability with o32 as all structures are exactly identical between > > o32 and n32. > > Why don't use o32 as is then, instead of creating a slightly different > ABI? If some software needs binary data to be identical, then it has to > select fixed-size types, e.g. int32_t, explicitly. While int32_t and > friends are quite a new standard, other ways were used for years to set up > such aspects, e.g. autoconf, imake, hand-written system-specific > preprocessor macros, etc., etc. No - the point is that all data types have the same size in N32. It was created explicitly as a transitional sop for people who didn't want to fix their code, but wanted a performance increase from their 64-bit hardware. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer
