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https://github.com/DoctorWkt/pdp7-unix.git
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OR syllables by default (allows multiple OPR instructions)
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Phil Budne
parent
2def710c48
commit
249ce47e44
125
tools/as7
125
tools/as7
@ -4,7 +4,7 @@
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# and convert them into PDP-7 machine code
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#
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# (c) 2016 Warren Toomey, GPL3
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# Tweaked by Phil Budne (expression parsing, "list" format)
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# Tweaked by Phil Budne (line, expression parsing, "list" format)
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#
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use strict;
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use warnings;
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@ -25,7 +25,6 @@ my $origline; # The original current input line of code
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my $line; # line being parsed
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my $stage = 1; # Pass one or pass two
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my $errors = 0; # set to non-zero on error
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my %Undef; # undefined symbols: only complain once
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my $line_error = ' ';
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my $file; # current file name
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my $lineno; # current line number
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@ -149,7 +148,7 @@ usage() if ( @ARGV < 1 );
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rsb => 0700144, # select PTR in binary mode
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psf => 0700201, # skip if PTP flag set
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pcf => 0700202, # clear PTP clag
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pcf => 0700202, # clear PTP flag
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psa => 0700204, # punch PTP in alphanumeric mode
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psb => 0700244, # punch PTP in binary mode
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@ -157,7 +156,7 @@ usage() if ( @ARGV < 1 );
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krb => 0700312, # read KBD buffer
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iors => 0700314, # input/output read status
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tsf => 0700401, # if if TTY output flag set
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tsf => 0700401, # skip if if TTY output flag set
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tcf => 0700402, # clear TTY output flag
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tls => 0700406, # load TTY output buffer and select
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@ -272,8 +271,9 @@ sub parse_file {
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close($IN);
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}
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# process a label and set its value to the location counter (only called on pass 1)
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# (if called on pass 2, should check if values are identical)
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# process a label and set its value to the location counter
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# only called on pass 1;
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# if called on pass 2, should check if values are identical
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sub process_label {
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my $label = shift;
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@ -294,25 +294,21 @@ sub process_label {
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}
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# Blame Phil for this....
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# parses global $line based on prefixes
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# (nibbling of a bit at a time)
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# parses global $line based on prefixes, nibbling of a bit at a time
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# (: and ; can appear in char literals)
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# handles multiple ';' separated words per line
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sub parse_line {
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$line_error = ' ';
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# Lose any leading whitespace
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$line =~ s{^\s*}{};
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while (1) {
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# Lose any leading whitespace
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$line =~ s{^\s*}{};
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$line_error = ' '; # clear listing error indicator
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return if ($line eq '' || $line =~ m{^"}); # empty or comment: quit
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print "parse_line: '$line'\n" if ($debug);
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return if ($line eq '');
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if ($line =~ m{^"}) { # remainder of line is comment
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return;
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}
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if ($line =~ s{^([a-z0-9\.]+):}{}) { # label
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while ($line =~ s{^([a-z0-9\.]+):\s*}{}) { # labels
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my $label = $1;
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# First pass: parse the labels
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@ -321,44 +317,40 @@ sub parse_line {
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process_label($1);
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}
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}
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else {
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my $lhs = undef;
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if ( $line =~ s{^(\S+)\s*=}{}) { # assignment
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$lhs = $1;
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}
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if ( $line =~ s{^(\S+)\s*=}{}) { # assignment
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my $lhs = $1;
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my $word = parse_expression();
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if ($lhs) {
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printf( "Setting variable %s to 0%o\n", $lhs, $word ) if ($debug);
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$Var{$lhs} = $word;
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printf("\t%06o %s\n", $word, $line_error) if ($stage == 2 && $format eq 'list');
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}
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else { # bare expression
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# Get its value on pass two and save to memory
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# Also save the input line that altered memory
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if ( $stage == 2 ) {
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my $location = $Var{'.'};
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$Mem[$location] = $word;
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$Mline[$location] = $origline;
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$origline = '';
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if ($format eq 'list') {
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printf( "%06o: %06o %s\n", $location, $word, $line_error);
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}
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printf( "Setting variable %s to 0%o\n", $lhs, $word ) if ($debug);
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$Var{$lhs} = $word;
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printf("\t%06o %s\n", $word, $line_error) if ($stage == 2 && $format eq 'list');
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}
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else { # bare expression
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# Get its value on pass two and save to memory
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# Also save the input line that altered memory
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my $word = parse_expression();
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if ( $stage == 2 ) {
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my $location = $Var{'.'};
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$Mem[$location] = $word;
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$Mline[$location] = $origline;
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$origline = '';
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if ($format eq 'list') {
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printf( "%06o: %06o %s\n", $location, $word, $line_error);
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}
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# Move up to the next location in both passes
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$Var{'.'}++;
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} # expr
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} # assignment or expression
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}
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# Move up to the next location in both passes
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$Var{'.'}++;
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} # expr
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# eat trailing whitespace and ";", if any
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$line =~ s{^\s*}{};
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$line =~ s{^;}{};
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$line =~ s{^\s*;?}{};
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} # while
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}
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# Blame Phil for this bit too...
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# Parse an expression off $line and return a PDP-7 word
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# as a series of whitespace separated "syllables"
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# and adds them together.
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# ORed, added, or subtracted
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sub parse_expression {
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my $word = 0;
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@ -366,23 +358,22 @@ sub parse_expression {
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while (1) {
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my $syllable = 0;
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my $sign = 1;
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my $op = '|';
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$line =~ s{^\s+}{};
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print " '$line'\n" if ($debug);
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if ($line eq '' || $line =~ m{^[";]}) { # EOL ; and " terminate expr
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printf("\tparse_expression => %#o\n", $word) if ($debug);
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return $word;
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}
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print " '$line'\n" if ($debug);
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if ($line =~ s{^-}{}) {
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# leading '-' negates upcomming syllable.
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$sign = -$sign;
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$op = '-';
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}
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else {
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# ignore leading '+'
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$line =~ s{^\+}{};
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elsif ($line =~ s{^\+}{}) {
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$op = '+';
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}
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if ($line =~ s{^<(.)}{}) { # <char
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@ -406,8 +397,7 @@ sub parse_expression {
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printf("\tlbl: %s: %#o\n", $sym, $syllable) if ($debug);
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}
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elsif ($stage == 2) {
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err('U', "$sym not defined") unless (defined $Undef{$sym});
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$Undef{$sym} = 1; # only complain once
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err('U', "$sym not defined")
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} # pass 2
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} # symbol
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elsif ( $line =~ s{^(\d+)([fb])}{} ) { # relative label
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@ -421,14 +411,31 @@ sub parse_expression {
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else {
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$syllable = $value + 0;
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}
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$syllable &= 0777777;
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}
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else {
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# From the BSD fortune file:
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# Ken Thompson has an automobile which he helped design.
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# Unlike most automobiles, it has neither speedometer,
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# nor gas gauge, nor any of the numerous idiot lights
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# which plague the modern driver. Rather, if the driver
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# makes any mistake, a giant "?" lights up in the center
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# of the dashboard. "The experienced driver",
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# he says, "will usually know what's wrong.
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err('?', "huh? '$line'");
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$line = '';
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$line = ''; # abort processing
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return $word;
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}
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$syllable = ($syllable * $sign) & 0777777;
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$word = ($word + $syllable) & 0777777;
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if ($op eq '+') {
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$word += $syllable;
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}
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elsif ($op eq '-') {
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$word -= $syllable;
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}
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else {
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$word |= $syllable;
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}
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$word &= 0777777;
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printf("\tsyllable: %#o word: %#o\n", $syllable, $word) if ($debug);
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}
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}
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