Files
ioccc/2011/richards
Landon Curt Noll a17fe36163 add tmp/fake.gen_inventory.sh tool
The new tool, tmp/fake.gen_inventory.sh, now adds
a fake .inventory.html file to each winner entry.

Once the winner2nventory tool is written, the .inventory.html
will contain links to all winner files listed in the inventory.
For now, the tmp/fake.gen_inventory.sh tool just creates
a placeholder file.
2023-11-01 00:47:43 -07:00
..
2023-05-13 11:45:33 +10:00
2023-11-01 00:47:43 -07:00
2023-10-23 10:18:20 -07:00
2023-05-08 04:36:28 -07:00
2023-07-06 21:49:38 -07:00

Most surprisingly portable

Gregor Richards
Richards@codu.org

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.md.

To use:

./richards

Try:

echo '10 9 8 7 6 5 4 3 2 1*p*p*p*p*p*p*p*p*p' | ./richards
echo '64 256 128 p/p*p' | ./richards

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.

This file is Copyright (c) 2023 by Landon Curt Noll. All Rights Reserved. You are free to share and adapt this file under the terms of this license:

Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)

For more information, see: https://creativecommons.org/licenses/by-sa/4.0/