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#!/usr/bin/perl
#
# Computes $1 modulo $2 with respect to the literal in $3
#
$Usage = "Usage: $0 <expr> <modulus> <literal>\n";
die $Usage unless $#ARGV == 2;
$_ = $ARGV[2];
$literal = $1 if /^\+?(\w+)$/;
die $Usage unless $literal;
$expr = $ARGV[0];
$modu = $ARGV[1];
# Find the term of highest degree in $modu
$_ = " $modu";
s/\b$literal\b/$literal\^1/g;
s/\^1\^/\^/g;
s/([+-])/ \1/g;
@terms = split(' ');
$degree = 0;
foreach $term (@terms) {
if ($term =~ /\b$literal\^(\d+)/)
{ $degree = $1 if $degree < $1; }
}
if ($degree == 0) {
print "0\n";
exit 0;
}
@high_terms = grep(/\b$literal\^$degree/, @terms);
$high_terms = join("", @high_terms);
open(STDOUT, "| samuel -b") || die;
print <<"__end"
E = $expr;
M = $modu;
S = $literal^$degree;
C = ($high_terms) / ?S;
(?E, ?S >> ?S - ?M / ?C);
__end
;
close STDOUT;
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