[comp.sys.att] Dhrystones

dca@toylnd.UUCP (09/06/87)

I looking at the dhrystones report the other day just for yucks and it struck
me that some of the machines reported default 'int' to 16 bits.  Some were
explicitly reported as such but I'll bet that some of the 8?86 boxes that
do so were not.  Note that the 68000 & 10 don't have support for the
32 bit x 32 bit = 64 bit multiply operation which means that array accesses
using an int tends to be rather slow.  Both the 68000 and the 68010 do,
however, have 16 bit x 16 bit = 32 bit so that using a short tends to be
much faster.  The 68020 does have the 32 x 32 = 64 so it's a different case.
For my own edification I went through dry.c and substitude 'short' anywhere
it said 'int' and re-ran dhrystone.  The results were a rather large gain.
Also they most of improved the compiler somewhat, because even the 32 bit
int results were slightly improved from the report.

INT SZ    REGS        NOREGS
32 bit    1049         987
16 bit    1318        1263

Not too shoddy eh?

David Albrecht