Landon Curt Noll
4ee4c731f7
While not strictly necessary, replacing the two ASCII tab characters in the markdown copyright comment makes it easier to detect problematic TAB indentation within markdown files. After this commit, only 90 markdown files have leading ASCII TAB characters. And again, while not strictly necessary, we can consider running expand on those 90 markdown files to see what effect that might have on the HTML files they produce. Replace leading ASCII TAB characters with multiples of 8 ASCII SPACE characters (the default action of the `expand(1)` tool) might have an negative effect on some HTML formatting where **hack-a-round** formatting was attempted to fix broken indentation caused by problematic ASCII TAB characters. Think of this as a baseline for evaluating leading TAB characters within markdown files. TODO: Consider either using `expand(1)` to replace leading ASCII TAB characters with multiples of 8 ASCII SPACE characters AND/OR modifying the appropriate `bin` tool to convert leading ASCII TAB characters into multiples of 8 ASCII SPACE characters.
To build:
make all
There is an alternate version that uses more memory. See alternate code below for more details.
To use:
./weisberg
Try:
./try.sh
If you have primes(1) installed you might also wish to try:
./primes.sh number
where number is a positive number, defaulting to 15. The try.sh
script will also do this.
Alternate code:
If you liked what you saw from the above program, and happen to have some 512 Megabytes of virtual memory lying around with to do something with you might try this version.
Alternate build:
make alt
Alternate use:
./weisberg.alt
Lesser systems will find this alternative version a good way to create a core file. :-)
Judges' remarks:
This entry confuses some C-preprocessors and some C-beautifiers.
We found one cpp that processed this source differently when
it was read on stdin instead of via cc -E.
Author's remarks:
Description
The following short program implements the "Yet Another" algorithm for generating prime numbers. It will generate all primes up to 33554432, displaying them to the standard output as it churns along. As 33554432 is rather large on most machines, this code may take quite some time to run to completion, so as an added feature, it will cease execution upon reception of a signal (any will do equally well), as well as in the event of a system shutdown or reboot.
Bugs
The alternative version (weisberg.c
compiled to weisberg.alt) has never actually run
to completion. After running for close to a week it had reached somewhere around
250e6, when it became necessary to test the reboot feature (which worked
remarkably well). As there are quite a lot of primes to be found before reaching
INT_MAX, the output produced can be quite overwhelming so it's recommended to pipe
the output through your favorite pager (more or less), and not output to a
paper output device (unless you have LOTS of paper).
Technical
The original "Yet Another Prime Program" algorithm used here was developed as a Computer Architecture course micro-programming exercise, and was designed to take full advantage of the UR300 micro-architecture to achieve blindingly fast speed. It was ported to C specifically for the IOCCC. In the conversion/obfuscation step some of (much of) the blazing speed was lost, but as a bonus, the understandability of the code was reduced to zero.