From         To         Computer       Processor        Program      # dec.     Time     Speed  Nr max dec.
   ----         --         --------       ---------        -------      ------     ----     -----  -----------
1988-02-25  1988-02-27  Apple II+       6502   @  1MHz  Calpi 9 43000C   22520  57h 54m      1.0        43,000
1991-02-09  1991-02-12  Atari Mega ST4  68000  @  8MHz  Calpi AST 10     64504  79h 28m 14s  6.0        65,000
1995-07-27  1995-07-27  Risc PC 600     ARM610 @ 30Mhz  Armpi 1         200000  15h 05m 50s  300   600,000,000
1995-07-28  1995-07-28  Risc PC 600     ARM610 @ 30Mhz  Armpi 2         200000   9h 12m 19s  500   600,000,000
1995-08-05  1995-08-05  Risc PC 600     ARM610 @ 30Mhz  Armpi 3         200000   7h 40m 07s  600   600,000,000
1995-08-07  1995-08-07  Risc PC 600     ARM610 @ 30Mhz  Armpi 4         200000   6h 54m 04s  660   600,000,000
1996-11-06  1996-11-06  Risc PC 600     SA-110 @202MHz  Armpi 4sa       200000   1h 59m 11s  2300  600,000,000

In each case, the following formula is used: pi/4 = arctan 1/2 + arctan 1/3.
But the algorithms are different. Concerning the long division by n, tables
are always used. On the Apple II, all the calculations are directly performed
in decimal; on the Atari and the Risc PC, pi is calculated in binary then
converted into decimal. Armpi 1 performs a 8-bit conversion (1 decimal digit
processed at once), Armpi 2 performs a 32-bit conversion (4 digits at once).
Armpi 3 groups the divisions by n, contrary to the previous programs:
(1/2^n + 1/3^n) / n is calculated, factorizing the division, instead of
(1/2^n) / n + (1/3^n) / n. Armpi 4 has a conversion that is a little faster.

The calculation is performed in a time proportional to the square of the number
of the calculated decimals, so that one can give a speed that does not depend
on the number of decimals. The speed given above has been normalized to 1 for
the Apple II.