Forth Prime Sieve by tjol

This is a straightforward port of Dave's algorithm to Forth (tested with GForth).

The state of the sieve is stored in dictionary-allocated memory, and allocated, initialized and deallocated on every iteration.

There are two versions:

• prime-bitarray.fs, storing the state in a bit field
• prime-bytearray.fs, storing every prime/not prime flag in a byte

prime-bitarray is closest to the original, prime-bytearray.fs is faster.

How to run

./run.sh

Output

gforth 0.7.3:

tjol-1bit;173 ;5.018379 ;1;algorithm=base,faithful=no,bits=1
tjol-8bit;265 ;5.001464 ;1;algorithm=base,faithful=no,bits=8

gforth 0.7.9_20210701:

tjol-1bit;465 ;5.002018 ;1;algorithm=base,faithful=no,bits=1
tjol-8bit;475 ;5.000922 ;1;algorithm=base,faithful=no,bits=8

gforth 0.7.9_20190627 in the Docker container

tjol-1bit;256 ;5.001076 ;1;algorithm=base,faithful=no,bits=1
tjol-8bit;418 ;5.0083 ;1;algorithm=base,faithful=no,bits=8

This is on a Ryzen 5 2600 running OpenSUSE Tumbleweed.