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fix Makefile for 2020/carlini and test a README.md style

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Landon Curt Noll committed 2023-03-10 21:06:21 -08:00
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2020/carlini/Makefile
+119 -379
View File
@@ -1,14 +1,41 @@
#!/usr/bin/env make #!/usr/bin/env make
# #
# 2020 makefile # IOCCC 2020 winning entry - carlini
################################################################################
# #
# This work by Landon Curt Noll, Simon Cooper, and Leonid A. Broukhis # Regarding individual entries:
# is licensed under: #
# IOCCC winning entry code may not work on your system. Even with standards,
# conditions and build environments change, especially when it comes to more
# extreme code such you might find in an IOCCC winner. Moreover, what was
# allowed and liked in one IOCCC contest may no longer be liked/allowed in
# later IOCCC years.
#
# Corrections on winning author and fixing typos in remarks are VERY WELCOME.
#
# GitHub pull requests are welcome:
#
# If you have a patch that might make running an entry work in modern Unix-like
# environments, please create a GitHub pull request for the IOCCC judges to
# consider.
#
# Suggestions and corrections regarding Makefiles, winning author information,
# fixing typos in remarks, and code patches are welcome via opening a GitHub
# issue or better yet, by creating a GitHub pull request for the IOCCC judges
# to consider. To form a GitHub issue or GitHub pull, please visit:
#
# https://github.com/ioccc-src/winner
#
################################################################################
# This work by Landon Curt Noll and Leonid A. Broukhis is licensed under:
# #
# Creative Commons Attribution-ShareAlike 3.0 Unported License. # Creative Commons Attribution-ShareAlike 3.0 Unported License.
# #
# See: http://creativecommons.org/licenses/by-sa/3.0/ # See: http://creativecommons.org/licenses/by-sa/3.0/
############################# #############################
# shell used by this Makefile # shell used by this Makefile
############################# #############################
@@ -19,264 +46,7 @@ SHELL= bash
# common tool locations # common tool locations
####################### #######################
# #
A2P= a2p include ../../var.mk
AR= ar
ASA= asa
AT= at
ATQ= atq
ATRM= atrm
AWK= awk
BANNER= banner
BASE64= base64
BASENAME= basename
BATCH= batch
BC= bc
BINHEX= binhex
BISON= bison
BUNZIP2= bunzip2
BZCAT= bzcat
BZCMP= bzcmp
BZDIFF= bzdiff
BZEGREP= bzegrep
BZFGREP= bzfgrep
BZGREP= bzgrep
BZIP2= bzip2
BZLESS= bzless
BZMORE= bzmore
C2PH= c2ph
C89= c89
C99= c99
CAL= cal
CALC= calc
CAT= cat
CD= cd
CHFLAGS= chflags
CHGRP= chgrp
CHMOD= chmod
CKSUM= cksum
CLANG= clang
CLANG_PLUSPLUS= clang++
CLEAR= clear
CMP= cmp
COL= col
COLLDEF= colldef
COLRM= colrm
COLUMN= column
COMPRESS= compress
CP= cp
CPIO= cpio
CPP= cpp
CRC32= crc32
CSH= csh
CSPLIT= csplit
CURL= curl
CUT= cut
C_PLUSPLUS= c++
C_PLUSPLUS_FILT= c++filt
DATE= date
DC= dc
DD= dd
DF= df
DIFF3= diff3
DIFF= diff
DIG= dig
DIRNAME= dirname
ED= ed
EGREP= egrep
ENV= env
EQN= eqn
ETAGS= etags
EXPECT= expect
EXPR= expr
FALSE= false
FGREP= fgrep
FILE= file
FIND2PERL= find2perl
FIND= find
FLEX= flex
FLEX_PLUSPLUS= flex++
FMT= fmt
FOLD= fold
FS_USAGE= fs_usage
FUNZIP= funzip
FUSER= fuser
GCC= gcc
GDIFFMK= gdiffmk
GENCAT= gencat
GENSTRINGS= genstrings
GETOPT= getopt
GETOPTS= getopts
GINDENT= gindent
GNUMAKE= gnumake
GREP= grep
GROFF= groff
GROFFER= groffer
GROG= grog
GROPS= grops
GROTTY= grotty
GUNZIP= gunzip
GVIM= gvim
GZCAT= gzcat
GZEXE= gzexe
GZIP_PROG= gzip
G_PLUSPLUS= g++
H2PH= h2ph
H2XS= h2xs
HASH= hash
HEAD= head
HOSTNAME_PROG= hostname
ICONV= iconv
ID= id
INDENT= indent
INFO= info
JOT= jot
KILL= kill
KSH= ksh
LAST= last
LD= ld
LESSECHO= lessecho
LEX= len
LINK= link
LN= ln
LS= ls
M4= m4
MAKE= make
MAN= man
MKDIR= mkdir
MKFIFO= mkfifo
MKTEMP= mktemp
MV= mv
NANO= nano
NASM= nasm
NEQN= neqn
NICE= nice
NL= nl
NM= nm
NOHUP= nohup
NROFF= nroff
NSLOOKUP= nslookup
OD= od
OPENSSL= openssl
PASTE= paste
PATCH= patch
PATHCHK= pathchk
PAX= pax
PERL= perl
PICO= pico
PR= pr
PRINTENV= printenv
PS= ps
PTAR= ptar
PTARDIFF= ptardiff
PTARGREP= ptargrep
PWD= pwd
PYDOC= pydoc
PYTHON= python
PYTHONW= pythonw
READLINK= readlink
RENICE= renice
RESET= reset
REV= rev
RI= ri
RM= rm
RMDIR= rmdir
RSYNC= rsync
RUBY= ruby
RVIM= rvim
SAY= say
SCP= scp
SCREEN= screen
SCRIPT= script
SDIFF= sdiff
SED= sed
SEQ= seq
SFTP= sftp
SH= sh
SHA1= sha1
SHA= sha
SHAR= shar
SHASUM5_18= shasum5.18
SHASUM= shasum
SIZE= size
SLEEP= sleep
SORT= sort
SSH= ssh
STAT= stat
STRIP= strip
STTY= stty
SUM= sum
SYNC= sync
TABS= tabs
TAIL= tail
TAR= tar
TEE= tee
TEST= test
TFTP= tftp
TIDY= tidy
TIME= time
TOP= top
TOUCH= touch
TPUT= tout
TPUT= tput
TR= tr
TROFF= troff
TRUE= true
TSET= tset
TSORT= tsort
UL= ul
UNAME= uname
UNCOMPRESS= uncompress
UNEXPAND= unexpand
UNIFDEF= unifdef
UNIFDEFALL= unifdefall
UNIQ= uniq
UNITS= units
UNLINK= unlink
UNZIP= unzip
UNZIPSFX= unzipsfx
UPTIME= uptime
UUDECODE= uudecode
UUENCODE= uuencode
UUIDGEN= uuidgen
VI= vi
VIEW= view
VIM= vim
VIMDIFF= vimdiff
W= w
WAIT4PATH= wait4path
WAIT= wait
WC= wc
WHAT= what
WHATIS= whatis
WHICH= which
WHO= who
WHOAMI= whoami
WHOIS= whois
WRTIE= write
XAR= xar
XARGS= xargs
XATTR= xattr
XXD= xxd
YACC= yacc
YES= yes
ZCAT= zcat
ZCMP= zcmp
ZDIFF= zdiff
ZEGREP= zegrep
ZFGREP= zfgrep
ZFORCE= zforce
ZGREP= zgrep
ZIP= zip
ZIPCLOAK= zipcloak
ZIPGREP= zipgrep
ZIPINFO= zipinfo
ZIPNOTE= zipnote
ZIPSPLIT= zipsplit
ZLESS= zless
ZMORE= zmore
ZNEW= znew
ZPRINT= zprint
ZSH= zsh
# Set X11_LIBDIR to the directory where the X11 library resides # Set X11_LIBDIR to the directory where the X11 library resides
# #
@@ -290,64 +60,25 @@ X11_LIBDIR= /opt/X11/lib
#X11_INCDIR= /usr/X11/include #X11_INCDIR= /usr/X11/include
X11_INCDIR= /opt/X11/include X11_INCDIR= /opt/X11/include
# CWARN - Silence warnings that ${CWARN} would normally complain about # Common C compiler warnings to silence
# CSILENCE -Compiler warnings
#
ifeq ($(CC),clang)
# clang CSILENCE and CWARN
# #
#CSILENCE= #CSILENCE=
#CSILENCE= -Wno-implicit-int CSILENCE= -Wno-overlength-strings
CSILENCE= -Wno-overlength-strings -Wno-missing-variable-declarations -Wno-format-nonliteral \
-Wno-unknown-warning-option
#
#CWARN= $CSILENCE}
#CWARN= -Wall $CSILENCE}
#CWARN= -Wall -Wextra $CSILENCE}
#CWARN= -Wall -Wextra -pedantic ${CSILENCE}
#CWARN= -Wall -Wextra -Weverything $CSILENCE}
CWARN= -Wall -Wextra -Weverything -pedantic ${CSILENCE}
else # Common C compiler warning flags
ifeq ($(CC),gcc)
# gcc CSILENCE and CWARN
# #
#CSILENCE= #CWARN= ${CSILENCE}
#CSILENCE= -Wno-implicit-int #CWARN= -Wall ${CSILENCE}
CSILENCE= -Wno-overlength-strings -Wno-unknown-warning-option #CWARN= -Wall -Wextra ${CSILENCE}
#
#CWARN= $CSILENCE}
#CWARN= -Wall $CSILENCE}
#CWARN= -Wall -Wextra $CSILENCE}
CWARN= -Wall -Wextra -pedantic ${CSILENCE} CWARN= -Wall -Wextra -pedantic ${CSILENCE}
else # Compiler standard
# default CSILENCE and WARN
#
#CSILENCE=
#CSILENCE= -Wno-implicit-int
CSILENCE= -Wno-overlength-strings -Wno-unknown-warning-option
#
#CWARN= $CSILENCE}
#CWARN= -Wall $CSILENCE}
#CWARN= -Wall -Wextra $CSILENCE}
CWARN= -Wall -Wextra -pedantic ${CSILENCE}
#CWARN= -Wall -Wextra -Weverything $CSILENCE}
#CWARN= -Wall -Wextra -Weverything -pedantic ${CSILENCE}
endif
endif
# compiler standard
# #
#CSTD= #CSTD=
#CSTD= -ansi #CSTD= -ansi
CSTD= -std=c11 CSTD= -std=gnu17
# compiler bit architecture # Compiler bit architecture
# #
# Some entries require 32-bitness: # Some entries require 32-bitness:
# ARCH= -m32 # ARCH= -m32
@@ -359,20 +90,21 @@ CSTD= -std=c11
# #
ARCH= ARCH=
# defines that are needed to compile # Defines that are needed to compile
# #
CDEFINE= CDEFINE=
#CDEFINE= -DIOCCC #CDEFINE= -DIOCCC
# include files that are needed to compile # Include files that are needed to compile
# #
CINCLUDE= CINCLUDE=
#CINCLUDE= -include stdlib.h #CINCLUDE= -include stdlib.h
#CINCLUDE= -include stdio.h #CINCLUDE= -include stdio.h
#CINCLUDE= -include stdlib.h -include stdio.h #CINCLUDE= -include stdlib.h -include stdio.h
#CINCLUDE= -I ${X11_INCDIR} #CINCLUDE= -I ${X11_INCDIR}
#CINCLUDE= `${SDL2_CONFIG} --cflags`
# optimization # Optimization
# #
# Most compiles will safely use -O2. Some can use only -O1 or -O. # Most compiles will safely use -O2. Some can use only -O1 or -O.
# A few compilers have broken optimizers or this entry make break # A few compilers have broken optimizers or this entry make break
@@ -385,38 +117,55 @@ CINCLUDE=
#OPT= -O2 #OPT= -O2
OPT= -O3 OPT= -O3
# default flags for ANSI C compilation # Default flags for ANSI C compilation
# #
CFLAGS= ${CSTD} ${CWARN} ${ARCH} ${CDEFINE} ${CINCLUDE} ${OPT} CFLAGS= ${CSTD} ${CWARN} ${ARCH} ${CDEFINE} ${CINCLUDE} ${OPT}
# Libraries needed to build # Libraries needed to build
# #
LIBS= LIBS=
#LIBS= -L ${X11_LIBDIR} #LIBS= -lm
#LIBS= -L ${X11_LIBDIR} -lX11
#LIBS= `${SDL2_CONFIG} --libs`
# ANSI compiler # C compiler to use
#
# Set CC to the name of your ANSI compiler.
#
# Some entries seem to need gcc. If you have gcc, set
# both CC and MAY_NEED_GCC to gcc.
#
# If you do not have gcc, set CC to the name of your ANSI compiler, and
# set MAY_NEED_GCC to either ${CC} (and hope for the best) or to just :
# to disable such programs.
# #
CC= cc CC= cc
#CC= clang #CC=clang
MAY_NEED_GCC= gcc #CC=gcc
# Compiler add-ons or replacements for clang only
#
ifeq ($(CC),clang)
#
CSILENCE+= -Wno-format-nonliteral -Wno-missing-variable-declarations \
-Wno-poison-system-directories
#
CWARN+= -Weverything
#
endif
# Specific add-ons or replacements for gcc only
#
ifeq ($(CC),gcc)
#
#CSILENCE+=
#
#CWARN+=
#
endif
############################## ##############################
# Special flags for this entry # Special flags for this entry
############################## ##############################
# #
OBJ= prog.o ENTRY= carlini
PROG= prog
#
OBJ= ${PROG}.o
DATA= DATA=
TARGET= prog TARGET= ${PROG}
# #
ALT_OBJ= ALT_OBJ=
ALT_TARGET= ALT_TARGET=
@@ -426,15 +175,19 @@ ALT_TARGET=
# build the entry # build the entry
################# #################
# #
all: ${TARGET} ${DATA} all: data ${TARGET}
@${TRUE} @${TRUE}
prog: prog.c .PHONY: all alt data everything clean clobber install \
love haste waste maker easter_egg sandwich \
supernova deep_magic magic charon pluto
${PROG}: ${PROG}.c
${CC} ${CFLAGS} $< -o $@ ${LIBS} ${CC} ${CFLAGS} $< -o $@ ${LIBS}
# alternative executable # alternative executable
# #
alt: ${ALT_TARGET} alt: data ${ALT_TARGET}
@${TRUE} @${TRUE}
# data files # data files
@@ -442,13 +195,15 @@ alt: ${ALT_TARGET}
data: ${DATA} data: ${DATA}
@${TRUE} @${TRUE}
# both all and alt
#
everything: all alt
############### ###############
# utility rules # utility rules
############### ###############
# #
everything: all alt
clean: clean:
${RM} -f ${OBJ} ${ALT_OBJ} ${RM} -f ${OBJ} ${ALT_OBJ}
@-if [ -f indent.c ]; then \ @-if [ -f indent.c ]; then \
@@ -463,24 +218,13 @@ clobber: clean
echo 'ate sandwich'; \ echo 'ate sandwich'; \
fi fi
nuke: clobber
@${TRUE}
dist_clean: nuke
@${TRUE}
install: install:
@echo "Surely you are performing, Dr. Science!" @echo "Dr. Spock says that is not logical!"
@${TRUE} @${TRUE}
# backwards compatibility # you may be able to misunderstand the source by reading indent.c
# #
build: all indent.c: ${PROG}.c
@${TRUE}
# you may be able to mis-understand the source by reading indent.c
#
indent.c: prog.c
@if which "${GINDENT}" >/dev/null 2>&1; then \ @if which "${GINDENT}" >/dev/null 2>&1; then \
echo ${RM} -f $@; \ echo ${RM} -f $@; \
${RM} -f $@; \ ${RM} -f $@; \
@@ -492,7 +236,7 @@ indent.c: prog.c
echo "${INDENT} < $< > $@"; \ echo "${INDENT} < $< > $@"; \
${INDENT} < $< > $@; \ ${INDENT} < $< > $@; \
else \ else \
echo "no intent prog found, ident $< yourself, sorry"; \ echo "no intent tool found, ident $< yourself, sorry"; \
echo "exit 1"; \ echo "exit 1"; \
exit 1; \ exit 1; \
fi fi
@@ -514,26 +258,21 @@ waste:
@echo 'haste' @echo 'haste'
@${TRUE} @${TRUE}
make: maker:
@echo 'We encourage you to attend a maker faire' @echo 'Participate in a maker faire'
@${TRUE} @${TRUE}
easter_egg: easter_egg:
@echo you expected to often mis-understand this $${RANDOM} magic @echo "you expected to often misunderstand this $${RANDOM} magic"
@echo chongo '<was here>' "/\\oo/\\" @echo "chongo '<was here>' /\\oo/\\"
@echo Eggy and Kitty @echo "Eggy"
fabricate fashion form frame manufacture produce: make sandwich: easter_egg
@${TRUE}
sandwich:
@if [ `id -u` -eq 0 ]; then \ @if [ `id -u` -eq 0 ]; then \
echo 'Okay.'; \ echo 'Okay.'; \
echo $${RANDOM}`date +%s`$${RANDOM} | \ echo "$${RANDOM}`date +%s`$${RANDOM}" > $@; \
${SHASUM} -a 512256 | \
${SED} -e 's/ .*//' > $@; \
else \ else \
echo 'Reall?!? Make it yourself.'; \ echo 'What? Make it yourself.'; \
exit 1; \ exit 1; \
fi fi
@@ -541,47 +280,48 @@ sandwich:
# as well as the West Coast Computer Faire and # as well as the West Coast Computer Faire and
# you might be confused different. :-) # you might be confused different. :-)
# #
supernova: nuke supernova: sandwich
@-if [ -r .code_anal ]; then \ @-if [ -r .code_anal ]; then \
${RM} -f .code_anal_v6; \ ${RM} -f .code_anal_v6; \
else \ else \
echo "planet deniers, like a few silly IAU members, are so cute when they try to defend their logic"; \ echo "planet deniers, like some members of the IAU, are so cute when they try to defend their logic"; \
fi fi
@echo A $@ helps ${MAKE} the elements that help form planets @echo "A $@ helps ${MAKE} the elements that help form planets"
@${TRUE} @${TRUE}
deep_magic: deep_magic: supernova
@-if [ -r .code_anal ]; then \ @-if [ -r .code_anal ]; then \
ccode_analysis --deep_magic 253d8c80830e2df66c018820004b3d4939821bbd7d781fc50d9e633797e44f65d1d62c707bb7e5a82c328a37bbf9ecb4c46fb56aa3f08641fcf45d10ba3c6081 --FNV1a_hash_512_bit "prog"; \ ccode_analysis --deep_magic 7889066cdbdf09b0408021754586e895be641cc9be29e7eafd3ca65359541f17 \
--FNV1a_hash_512_bit -v2 "${PROG}" "${PROG}.c"; \
else \ else \
echo "Wrong! Do it again!"; \ echo "Wrong! Do it again!"; \
sleep 1; \ sleep 2; \
echo "Wrong! Do it again!"; \ echo "Wrong! Do it again!"; \
sleep 1; \ sleep 2; \
echo "Wrong! Do it again!"; \ echo "Wrong! Do it again!"; \
fi fi
@${TRUE} @${TRUE}
magic: deep_magic magic: deep_magic
@-if [ -r .code_anal ]; then \ @-if [ -r .code_anal ]; then \
ccode_analysis --level 391581 --mode 216193 --state Riesel --FNV1a_hash_512_bit "prog"; \ ccode_analysis --level 20003 --mode 5717175 --FNV1a_hash_512_bit -v2 "${PROG}" "${PROG}.c"; \
else \ else \
echo "If you don't eat yer meat, you can't have any pudding!"; \ echo "If you don't eat yer meat, you can't have any pudding!"; \
echo "How can you have any pudding if you don't eat yer meat?!"; \ echo "How can you have any pudding if you don't eat yer meat?!"; \
echo "Be careful with that axe, Eugene."; \
fi fi
@${TRUE} @${TRUE}
# The IOCCC resident astronomer states # The IOCCC resident astronomer states
# #
charon: supernova charon: magic
@echo $@ is a dwarf planet @echo "$@ is a dwarf planet"
@echo dwarf is a type of planet @echo "dwarf is a type of planet"
@echo therefore we continue to tell the IAU that $@ is a planet @echo "therefore IAU, $@ is a planet"
pluto: supernova pluto: charon
${MAKE} charon ${MAKE} charon
@echo $@ is a dwarf planet @echo "$@ is a dwarf planet"
@echo dwarf is a type of planet @echo "dwarf is a type of planet"
@echo therefore, $@ is a planet @echo "therefore, $@ is a planet"
@echo having lots of planets is good feature because supernovae can help ${MAKE} a lot of them @echo "having lots of planets is good feature because supernovae can help ${MAKE} a lot of them"
2020/carlini/README.md
+104 -61
View File
@@ -1,47 +1,56 @@
# Best of show - abuse of libc # Best of show - abuse of libc
```
Nicholas Carlini <nicholas@carlini.com> Nicholas Carlini <nicholas@carlini.com>
<https://nicholas.carlini.com> <https://nicholas.carlini.com>
```
## To build:
The code for this entry can be found in prog.c ```sh
make
```
## Judges' comments: ### To run:
### To use:
make
./prog
```sh
./prog
```
### Try: ### Try:
# Play with a friend, P1 and P2, squares are numbered 1..9 ```sh
./prog # Play with a friend, P1 and P2, squares are numbered 1..9
./prog
```
## Judges' comments:
### Selected Judges Remarks:
This program consists of a single print statement wrapped in a while loop. You This program consists of a single print statement wrapped in a while loop. You
would not think that this would amount to much, but you would be very, very would not think that this would amount to much, but you would be very, very
wrong. A clue to what is happening and how this works is encoded in the wrong. A clue to what is happening and how this works is encoded in the
ASCII art of the program source. ASCII art of the program source.
## Author's comments: ## Author's comments:
HOW ABOUT A NICE GAME OF <strike>CHESS</strike>TIC-TAC-TOE? HOW ABOUT A NICE GAME OF <strike>CHESS</strike>TIC-TAC-TOE?
### USAGE ### USAGE
cc -o prog prog.c ```sh
./prog cc -o prog prog.c
./prog
```
Alternates between P1 and P2. Enter a digit [1-9] to move: Alternates between P1 and P2. Enter a digit [1-9] to move:
1 | 2 | 3 ```
--------- 1 | 2 | 3
4 | 5 | 6 ---------
--------- 4 | 5 | 6
7 | 8 | 9 ---------
7 | 8 | 9
```
The game ends if: The game ends if:
@@ -49,7 +58,6 @@ The game ends if:
* All squares are taken; neither player wins * All squares are taken; neither player wins
* A player makes an illegal move; their opponent wins * A player makes an illegal move; their opponent wins
### LIMITATIONS ### LIMITATIONS
Bad things may happen if the entered move is outside of the range [1..9] Bad things may happen if the entered move is outside of the range [1..9]
@@ -69,16 +77,19 @@ compilers unhappy, and others slow. (For example, passing GCC the flags -Wall
Under some terminals the program may exit early. The following should always work: Under some terminals the program may exit early. The following should always work:
echo "1 2 3 4 5 6 7" | ./prog ```sh
echo "1 2 3 4 5 6 7" | ./prog
```
### OBFUSCATION ### OBFUSCATION
The entirety of the program consists of a single iterated call to printf. The entirety of the program consists of a single iterated call to printf.
int main() { ```c
while(*d) printf(fmt, arg); int main() {
} while(*d) printf(fmt, arg);
}
```
Here, `fmt` is a single string, and `arg` is a series of arguments to printf. Here, `fmt` is a single string, and `arg` is a series of arguments to printf.
@@ -102,7 +113,6 @@ This program uses three printf format specifiers.
- `%n` takes a pointer and writes (!!) the number of bytes printed so far. - `%n` takes a pointer and writes (!!) the number of bytes printed so far.
Okay, everyone probably knows this. Let's get a bit more advanced. Okay, everyone probably knows this. Let's get a bit more advanced.
Format specifiers can take extra "arguments". Format specifiers can take extra "arguments".
@@ -115,14 +125,17 @@ Format specifiers can take extra "arguments".
- `"%3$.*4$d"`: print argument 3 to printf with as many zeros as in argument 4. - `"%3$.*4$d"`: print argument 3 to printf with as many zeros as in argument 4.
For example, the following expression For example, the following expression
printf("%1$.*2$d%3$hhn", 5, 10, &x) ```c
printf("%1$.*2$d%3$hhn", 5, 10, &x)
```
will have the same effect as if we had written will have the same effect as if we had written
x = 10; ```c
x = 10;
```
because it will print out `0000000005` (5 padded to size 10) and then write the because it will print out `0000000005` (5 padded to size 10) and then write the
number of bytes written to x. number of bytes written to x.
@@ -143,27 +156,39 @@ We can use format strings to compute the OR/NOT of arbitrary "bits".
We'll start with the simplest, OR: We'll start with the simplest, OR:
printf("%1$s%2$s%3$hhn", a, b, c) ```c
printf("%1$s%2$s%3$hhn", a, b, c)
```
will compute will compute
*c = strlen(a) + strlen(b) ```c
*c = strlen(a) + strlen(b)
```
but given that `strlen(x)` is `1` for a 1-bit and `0` for a 0-bit, we have but given that `strlen(x)` is `1` for a 1-bit and `0` for a 0-bit, we have
*c = a | b ```c
*c = a | b
```
Computing the NOT of a single value is also easy: Computing the NOT of a single value is also easy:
printf("%1$255d%1$s%hhn", a, b) ```c
printf("%1$255d%1$s%hhn", a, b)
```
will compute will compute
*b = (strlen(a)+255)%256 = strlen(a)-1 ```c
*b = (strlen(a)+255)%256 = strlen(a)-1
```
and again, because `strlen(x)` is either `1` or `0` we have and again, because `strlen(x)` is either `1` or `0` we have
*c = !b ```c
*c = !b
```
From here we can compute any binary circuit. Doing something efficient, From here we can compute any binary circuit. Doing something efficient,
though, still takes work. though, still takes work.
@@ -177,11 +202,13 @@ To detect who has won, we implement the following logic. Let A, B, and C be
pointers to three squares in a row to test, and D be where to save if there is a pointers to three squares in a row to test, and D be where to save if there is a
win or not. win or not.
"%A$s%B$s%C$s%1$253d%11$hhn" // r11 = !(*A & *B & *C) ```c
ZERO "%A$s%B$s%C$s%1$253d%11$hhn" // r11 = !(*A & *B & *C)
"%11$s%1$255d%11hhn" // r11 = !r11 ZERO
ZERO "%11$s%1$255d%11hhn" // r11 = !r11
"%11$s%D$s%D$hhn" // *D = *D | r11 ZERO
"%11$s%D$s%D$hhn" // *D = *D | r11
```
That is, we set `*D` to `1` if there is a three-in-a-row. We repeat this for all That is, we set `*D` to `1` if there is a three-in-a-row. We repeat this for all
possible three-in-a-row configurations, for both players. possible three-in-a-row configurations, for both players.
@@ -189,7 +216,9 @@ possible three-in-a-row configurations, for both players.
The ZERO macro ensures that the number of bytes written out is 0 mod 256 with The ZERO macro ensures that the number of bytes written out is 0 mod 256 with
the following expression the following expression
"%1$hhn%1$s" (repeated 256 times) ```c
"%1$hhn%1$s" (repeated 256 times)
```
where argument 1 is a pointer to a temporary variable followed by a null byte. where argument 1 is a pointer to a temporary variable followed by a null byte.
@@ -206,11 +235,15 @@ bits to Xs and Os to print out. This is actually rather straightforward. Given
in 1$ the pointer to player 1's square, and 2$ the pointer to player 2's, and in 1$ the pointer to player 1's square, and 2$ the pointer to player 2's, and
in 3$ the pointer to the board string, we can compute in 3$ the pointer to the board string, we can compute
"%1$s" (repeated 47 times) "%2$s" (repeated 56 times) %1$32d%3$hhn" ```c
"%1$s" (repeated 47 times) "%2$s" (repeated 56 times) %1$32d%3$hhn"
```
which will, in effect, compute which will, in effect, compute
*r3 = (*r1) * 47 + (*r2) * 56 + 32 ```c
*r3 = (*r1) * 47 + (*r2) * 56 + 32
```
which will output `' '` if neither are true, `'X'` if r1 is, or `'O'` if r2 is. which will output `' '` if neither are true, `'X'` if r1 is, or `'O'` if r2 is.
@@ -220,7 +253,9 @@ which will output `' '` if neither are true, `'X'` if r1 is, or `'O'` if r2 is.
In order to be able to finally display the board, while still only using one In order to be able to finally display the board, while still only using one
printf statement, we finish the statement with printf statement, we finish the statement with
"\n\033[2J\n%26$s" ```c
"\n\033[2J\n%26$s"
```
which is the escape sequence to clear the screen, and then prints argument 26. which is the escape sequence to clear the screen, and then prints argument 26.
Argument 26 is a pointer to a char* in memory, that initially is undefined, Argument 26 is a pointer to a char* in memory, that initially is undefined,
@@ -229,12 +264,14 @@ tic-tac-toe board.
After the board, we need to print one of the following strings: After the board, we need to print one of the following strings:
P1>_ ```
P2>_ P1>_
P1 WINS P2>_
P2 WINS P1 WINS
P1 TIES P2 WINS
P2 TIES P1 TIES
P2 TIES
```
Depending on if it's P1 or P2's turn to move, the game is over and someone Depending on if it's P1 or P2's turn to move, the game is over and someone
won, or the game is over and it is a draw. won, or the game is over and it is a draw.
@@ -242,7 +279,9 @@ won, or the game is over and it is a draw.
This turns out not to be as hard as it might look. Using the same trick as This turns out not to be as hard as it might look. Using the same trick as
before, we set byte four to be before, we set byte four to be
*byte4 = is_win * 'W' + is_tie * 'T' ```c
*byte4 = is_win * 'W' + is_tie * 'T'
```
The byte `'I'` and `'S'` can always be the same, and we do the same for `'E'`/`'N'`. The byte `'I'` and `'S'` can always be the same, and we do the same for `'E'`/`'N'`.
@@ -254,19 +293,23 @@ ends. It should just exit.
One option would be to implement the logic as One option would be to implement the logic as
printf() ```c
while (*ok) { printf()
scanf(); while (*ok) {
printf(); scanf();
} printf();
}
```
but this would DOUBLE the number of calls to printf we require. So instead we but this would DOUBLE the number of calls to printf we require. So instead we
implement it like this implement it like this
while (*ok) { ```c
scanf(); while (*ok) {
printf(); scanf();
} printf();
}
```
(In reality we actually pass `scanf()` as an argument to avoid the extra (In reality we actually pass `scanf()` as an argument to avoid the extra
statement, but it has the same effect.) statement, but it has the same effect.)
@@ -276,10 +319,10 @@ block before the first `printf()`, but we initialize the `scanf()` format to the
string so that it returns right away without blocking. The first time the `printf()` string so that it returns right away without blocking. The first time the `printf()`
call runs, it writes out `"%hhd"` to create the `scanf()` format string. call runs, it writes out `"%hhd"` to create the `scanf()` format string.
----------------------------------------------------------------------------------------------------- ## Copyright:
(c) Copyright 1984-2020, [Leo Broukhis, Simon Cooper, Landon Curt Noll][judges] - All rights reserved (c) Copyright 1984-2020, [Leo Broukhis, Simon Cooper, Landon Curt Noll][judges] - All rights reserved
This work is licensed under a [Creative Commons Attribution-ShareAlike 3.0 Unported License][cc]. This work is licensed under a [Creative Commons Attribution-ShareAlike 3.0 Unported License][cc].
[judges]: http://www.ioccc.org/judges.html [judges]: http://www.ioccc.org/judges.html
[cc]: http://creativecommons.org/licenses/by-sa/3.0/ [cc]: http://creativecommons.org/licenses/by-sa/3.0/
-----------------------------------------------------------------------------------------------------