#! /bin/sh
#
# Exercise script.  Throws random numbers under 500 digits at the
#  multiplier and at baseline(), trying to find values where the
#  multiplier returns something different from baseline().
#
# Generates digit counts by picking a random three-digit number,
#  dividing it by 4, and adding that to 250.  Then, a random digit is
#  used to select a number of times to divide this by 2.  The result is
#  a random digit count.  That many digits are read and used as a
#  number.  After generating two numbers this way, a calc script is
#  generated which multiplies them both with * and with baseline(),
#  then subtracting the one from the other; this script is run, looking
#  for a nonzero output.
#
# 2^197=200867255532373784442745261542645325315275374222849104412672
loops=0
while :
do
	d=`skipcat 0 25 < /dev/urandom | hexdump -v -e '1/1 "%02x"' | cvtbase -m200 x b | sed -e 's/^...//' | cvtbase -m60 b d`
	case $d in 2*) ;; *) echo $d | sed -e 's/./& /g' -e 's/ $//' | tr \  \\n;; esac
done | ( exec 3<&0
while :
do
	loops=$(($loops+1))
	read h 0<&3
	read t 0<&3
	read u 0<&3
	dc1=$((((1$h$t$u-1000)/4)+250))
	read s 0<&3
	case $s in
		0|1)	dc1=$(($dc1/4));;
		2|3|4)	dc1=$(($dc1/2));;
	esac
	read h 0<&3
	read t 0<&3
	read u 0<&3
	dc2=$((((1$h$t$u-1000)/4)+250))
	read s 0<&3
	case $s in
		0|1)	dc2=$(($dc2/4));;
		2|3|4)	dc2=$(($dc2/2));;
	esac
	n1=`skipcat 0 $(($dc1*2)) 0<&3 | tr -dc 0-9`
	n2=`skipcat 0 $(($dc2*2)) 0<&3 | tr -dc 0-9`
	diff=`
		(	echo \?p1023
			echo a=$n1\;
			echo b=$n2\;
			echo '(a*b)-baseline(a,b)'
		) | calc -q | tail -1
		`
	echo $loops
	case $diff in
		0)	;;
		*)	echo $n1
			echo $n2
			echo $diff
			exit 1
			;;
	esac
done
)