Files
ioccc/2011/richards
Cody Boone Ferguson ffdb219ceb Change references of 'alt code' to 'alternate code'
This was done by:

    sgit -e 's/alt code/alternate code/g' . ; git co tmp/OLD_manifest

as well as updating the tmp/manifest.numbers spreadsheet and exporting
to the CSV file (though that would not strictly be necessary).

The way this works means that the update manifest script does not need
to be run as it sgit(1) touched the .entry.json files (any that needed
to be updated) and so would any index.html files. An example for both
.entry.json and index.html files being modified due to manifest is
2012/kang.

Numerous Makefiles were updated, any try scripts that had 'alt code'
instead of 'alternate code' and README.md/index.html files (unrelated to
the manifest as 'alt code' was used in other places too) and obviously
the manifest.numbers spreadsheet.

However to be safe I will do a run of the manifest script in a bit even
though it should not be necessary. If no commits are made it means all
is good and if any commits are made for the manifest it means that I
did not think of something (or else I made another change after this).
2024-05-30 08:02:32 -07:00
..
2024-03-13 00:38:46 -07:00
2023-05-08 04:36:28 -07:00
2023-07-06 21:49:38 -07:00

To build:

    make

Bugs and (Mis)features:

The current status of this entry is:

    STATUS: doesn't work with some platforms - please help us fix

For more detailed information see 2011/richards in bugs.html.

To use:

    echo expression | ./richards

Try:

    ./try.sh

Judges' remarks:

Oh no, yet another dc-style calculator? (see 2000/dlowe using an embedded Perl interpreter and deemed Worst Abuse of the Rules). Well, this one does it (expression calculation, that is, not the rule abuse) in a different way. The author claims that his calculator does just-in-time compilation. What would you do to prove or disprove his claim without attempting to unravel the source?

Author's remarks:

This is an implementation of the classic UNIX dc command, the reverse Polish calculator. Actually it's a pretty bad implementation, since it only implements 32-bit integers (well, sizeof(int)-sized integers). It only implements the commands +, -, *, /, p (only for numbers), register stacks, macros and comparisons. Wow, you'd think I could've done better in 2K of code.

OH! I forgot to mention! It's a JIT.

Wait, don't stop reading! I know what you're thinking, platform-specific code is discouraged in IOCCC. But do you see any platform-specific code? There's no assembler here! This JIT works on a dozen platforms, and the only platform-specific assumptions it makes are that the stack grows down and integers are at least 32-bit.

You will probably get warnings while compiling the code. In particular:

  • If your system requires the inclusion of alloca.h to use alloca, use the compile flag -DAH.

  • If your system cannot use mmap(), use the compile flag -DNM.

  • I don't include any headers I don't strictly need to, so you'll get warnings about (at least) memcpy(), isdigit(), atoi(), calloc(), malloc() and alloca() if you didn't use -DAH.

    • NOTE from judges: we added these includes in 2023.
  • GCC likes to complain about while (a = b) (assignments as a condition).

  • I don't return from main(), even though it's declared to return int.

Platforms on which all known/tested optimization levels work with no additional flags:

  • gcc 4.6.2 + x86[_64] + GNU/Linux, Mac OS X or Windows
  • clang 2.9-16 + x86[_64] + GNU/Linux or Mac OS X
  • tcc 0.9.25
  • gcc 4.4.5 + alpha, arm, mips[el], powerpc[64], s390x (IBM zSeries)
  • gcc 4.1.3 + vax + NetBSD

Platforms which work but not at all optimization levels or needing special flags:

  • owcc 1.9 + x86 + Windows: Needs -DNM -DAH -fno-stack-check
  • gcc 4.4.5 + sh4: -O0 works, higher optimization levels don't work for unknown reasons.