Re: DECstation 2100 floating point

[George Harvey <fr30%dial.pipex.com@localhost>]

On Thu, 31 Mar 2011 22:51:35 +0900
Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost> wrote:

> I tried pkgsrc/benchmark/flops on NetBSD/cobalt 5.99.44 and
> it shows a bit strange result:

That's odd, on my RaQ 2, running NetBSD/Cobalt 5.0.2, with flops
installed from pkgsrc, I get normal-looking results:

-bash-2.05b$ which flops
/usr/pkg/bin/flops
-bash-2.05b$ flops

   FLOPS C Program (Double Precision), V2.0 18 Dec 1992

   Module     Error        RunTime      MFLOPS
                            (usec)
     1      1.3358e-12      0.2935     47.7073
     2      2.0517e-13      0.1487     47.0793
     3      1.7542e-14      0.2976     57.1277
     4     -5.4512e-14      0.2855     52.5427
     5      3.3307e-16      0.4783     60.6303
     6     -1.9040e-14      0.3537     81.9794
     7      2.6034e-11      0.4904     24.4680
     8     -5.4068e-14      0.3737     80.2754

   Iterations      =   64000000
   NullTime (usec) =     0.0000
   MFLOPS(1)       =    49.9517
   MFLOPS(2)       =    41.4133
   MFLOPS(3)       =    56.7492
   MFLOPS(4)       =    69.4380

George

> ---
> # ./flops 
> 
>    FLOPS C Program (Double Precision), V2.0 18 Dec 1992
> 
>    Module     Error        RunTime      MFLOPS
>                             (usec)
>      1     -2.5193e+01      0.4895     28.5980
>      2             nan     -0.0000  -4226415.0942
>      3      1.4544e-14     33.3001      0.5105
>      4      1.6415e+09     31.9524      0.4694
>      5      1.8627e+17     69.2567      0.4187
>      6     -1.1475e+87     40.3928      0.7179
>      7      5.1090e+02     54.9010      0.2186
>      8     -2.9167e-01      0.0000  33103448.4122
> 
>    Iterations      =    -640000
>    NullTime (usec) =     0.0000
>    MFLOPS(1)       =     1.5616
>    MFLOPS(2)       =     0.3848
>    MFLOPS(3)       =     0.6340
>    MFLOPS(4)       =     0.8614
> 
> ---
> 
> flops.c itself might have some non-C99-compliant statements
> and aggressive gcc4 generates unintended code?
> 
> ---
> Izumi Tsutsui
>