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Cody Boone Ferguson cb8d8924a7 Improve links to bugs.html in README.md files

In other words rather than have the link name in the form of:

    1984 decot bugs

it is now:

    1984/decot in bugs.html

so that it matches how the entry itself looks (as in how it's
identified) and to say where (what file) it is (in). The reason it says
'in bugs.html' rather than 'bugs' (saying that the entry has bugs) is
because not all are bugs and it's saying where to see it anyway. But
some are features, others are missing links or files or other things
like that and to keep the same form it now says 'in bugs.html'.

This was done with my sgit(1) tool like:

    sgit -e 's,\([0-9][0-9][0-9][0-9]\) \([-a-z\.0-9]*\) bugs,\1/\2 in bugs.html,g' '*/*md'

The link to bugs.html itself has the path '../../bugs.html'. This is
important as it's meant to be rendered in the browser. At first this was
not remembered and I did something like:

    sgit -e 's,\[\([0-9][0-9][0-9][0-9]\) \([-a-z\.0-9]*\) bugs\](../../bugs.html,\[\1/\2 in bugs.html\](%%REPO_URL%%/bugs.html,g' '*/*md'

but this was changed to the simpler one due to the problem described
above. It's worth putting this note here as a reminder, though, so I
have included it here.

2024-05-04 09:21:09 -07:00

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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.

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