When is 8 > 16?

[toml_12953]

I recently benchmarked the Casio VX-4 (64K RAM) against the Casio Z-1GR (64K RAM), Casio FX-890P (96K RAM), and Sharp PC G850V (32K RAM).

The benchmark used was from
https://www.hpmuseum.org/cgi-sys/cgiwrap...i?read=700.

I used the structured C program (see code below) for the tests. All the calculators were able to run this version.

The VX-4 uses an 8-Bit Hitachi HD61700 CPU, the Z-1GR and FX-890P use a 16-bit Intel 80186 compatible CPU and the Sharp PC G850V uses an 8-bit Zilog Z-80-compatible CPU.

I was really expecting the Z-1GR and FX-890P to walk away with the prize for fastest of the bunch. I was surprised that the Sharp PC G850V was about three times faster than those 16-bit calculators! The VX-4 was so slow as to be unusable. The other Casios limped along slowly. The Sharp was no speed demon compared to modern calculators but it did win the vintage challenge!

Code:

 main()
 {
   int x,y,r,s,t,n,a[9];

   for(n=1000;n>0;--n){
     r=8;
     s=0;
     x=0;
     do{
       a[++x]=r;
       do{
         ++s;
         y=x;
         while(y>1)
           if (!(t=a[x]-a[--y]) || x-y==abs(t)){
             y=0;
             while(!--a[x])
               --x;
           }
       } while(y!=1);
     } while(x!=r);
   }
   printf("%d",s);
 }

[xerxes]

The C interpreter of the HD61700 pockets seems to be very inefficient. While C is much faster than Basic on the Z-1GR or PC-G850V, it's vice versa on the VX-4.

An explanation for the faster PC-G850V is the 8.0 MHz clock vs. 3.68 MHz on the Z-1GR and only 0,91 MHz on the VX-4.