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https://github.com/livingcomputermuseum/pdp7-unix.git
synced 2026-02-08 17:32:09 +00:00
Ken Thompson sent e-mail in to explain that there can be labels mid-line, such as
sys write; 1:0; 4 so I modified the assembler logic to support this, and added some code to write_test.s to verify that it works.
This commit is contained in:
Warren Toomey
142
tools/as7
142
tools/as7
@@ -20,44 +20,51 @@ my @Mline; # Source lines associated with mem locations
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my $origline; # The current input line of code
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my $stage = 1; # Pass one or pass two
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my $debug = 0; # Run in debug mode
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### Main program ###
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# Optional debug argument
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if ( ( @ARGV > 0 ) && ( $ARGV[0] eq "-d" ) ) {
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$debug = 1;
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shift(@ARGV);
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}
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# Check the arguments
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die("Usage: $0 file1.s [file2.s ...]\n") if ( @ARGV < 1 );
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die("Usage: $0 [-d] file1.s [file2.s ...]\n") if ( @ARGV < 1 );
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# Define the syscalls as variables so that
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# I don't have to hand-code the logic below.
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# Also, start with the location counter at zero
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%Var= (
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'.' => 0,
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save => 1,
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getuid => 2,
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open => 3,
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read => 4,
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write => 5,
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creat => 6,
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seek => 7,
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tell => 8,
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close => 9,
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link => 10,
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unlink => 11,
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setuid => 12,
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rename => 13,
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exit => 14,
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time => 15,
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intrp => 16,
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chdir => 17,
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chmod => 18,
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chown => 19,
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badcal => 20,
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syslog => 21,
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capt => 23,
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rele => 24,
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status => 25,
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smes => 27,
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rmes => 28,
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fork => 29
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%Var = (
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'.' => 0,
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save => 1,
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getuid => 2,
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open => 3,
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read => 4,
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write => 5,
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creat => 6,
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seek => 7,
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tell => 8,
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close => 9,
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link => 10,
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unlink => 11,
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setuid => 12,
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rename => 13,
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exit => 14,
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time => 15,
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intrp => 16,
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chdir => 17,
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chmod => 18,
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chown => 19,
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badcal => 20,
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syslog => 21,
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capt => 23,
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rele => 24,
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status => 25,
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smes => 27,
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rmes => 28,
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fork => 29
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);
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# Parse all the files
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@@ -68,16 +75,16 @@ foreach my $file (@ARGV) {
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# Now do it all again, pass two
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$Var{'.'} = 0;
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$stage = 2;
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print("Now in stage 2\n") if ($debug);
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foreach my $file (@ARGV) {
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parse_file($file);
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}
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# Now print out the contents of memory
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for my $i ( 0 .. $#Mem ) {
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if (defined($Mem[$i])) {
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printf("%06o: %06o\t%s\n",
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$i, $Mem[$i], $Mline[$i] || "");
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}
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if ( defined( $Mem[$i] ) ) {
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printf( "%06o: %06o\t%s\n", $i, $Mem[$i], $Mline[$i] || "" );
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}
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}
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exit(0);
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@@ -91,39 +98,39 @@ sub parse_file {
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# Lose the end of line and any leading/trailing whitespace
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# Discard any comments and preceding comment whitespace
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chomp($line);
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$origline= $line;
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$origline = $line;
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$line =~ s{^\s+}{};
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$line =~ s{\s+$}{};
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$line =~ s{\s*\".*}{};
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#print("=>$line<=\n");
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# Split into a section with possible labels and a
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# section with definitely no labels. The ? makes the
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# first pattern less greedy. Labels and statements.
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$line =~ m{(.*?)([^:]*$)};
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my $labelsect = $1;
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my $stmntsect = $2;
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# Split the line into commands that are ; separated
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# and parse each one
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foreach my $cmd ( split( /;\s*/, $line ) ) {
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#print(">$labelsect< >$stmntsect<\n");
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# Split into a section with possible labels and a
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# statement section with definitely no labels. The ?
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# makes the first pattern less greedy.
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#print("cmd is >$cmd<\n");
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$cmd =~ m{(.*?)([^:]*$)};
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my $labelsect = $1;
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my $statement = $2;
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# Split $labelsect into labels using the : character
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my @labellist = split( /:\s*/, $labelsect );
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#print(">$labelsect< >$statement<\n");
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# Split $stmntsect into statements using the ; character
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# Trim any whitespace first
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$stmntsect =~ s{^\s+}{};
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my @stmntlist = split( /;\s*/, $stmntsect );
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# Split $labelsect into labels using the : character
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my @labellist = split( /:\s*/, $labelsect );
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# First pass: parse the labels
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if ( $stage == 1 ) {
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foreach my $l (@labellist) { parse_label($l); }
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# First pass: parse the labels
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if ( $stage == 1 ) {
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foreach my $l (@labellist) {
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parse_label($l);
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}
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}
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# Parse the statements on both passes
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parse_statement($statement);
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}
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# Parse the statements on both passes
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foreach my $s (@stmntlist) {
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parse_statement($s);
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}
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#print("\n");
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}
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close($IN);
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}
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@@ -153,6 +160,12 @@ sub parse_statement {
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my $location = $Var{'.'};
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#printf( "Location: 0%o\n", $location );
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# Empty statement, nothing to do
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return if ( $statement =~ m{^\s*$} );
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# Lose any leading whitespace
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$statement =~ s{^\s*}{};
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# It's an assignment statement: lhs = rhs
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if ( $statement =~ m{(\S+)\s*=\s*(\S+)} ) {
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my $lhs = $1;
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@@ -163,6 +176,7 @@ sub parse_statement {
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my $result = parse_expression($rhs);
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die("expression $rhs has no value in assignment\n")
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if ( !defined($result) );
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#printf( "Setting variable %s to 0%o\n", $lhs, $result );
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$Var{$lhs} = $result;
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return;
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@@ -173,7 +187,7 @@ sub parse_statement {
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# Also save the input line that altered memory
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if ( $stage == 2 ) {
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my $val = parse_expression($statement);
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$Mem[$location] = $val & 0777777;
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$Mem[$location] = $val & 0777777;
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$Mline[$location] = $origline;
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#printf( "Saving 0%o into memory location 0%o\n", $val, $location );
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}
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@@ -190,8 +204,8 @@ sub parse_expression {
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# If it's a defined variable ( . , .. , etc.)
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# return the value
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return($Var{$expression})
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if (defined($Var{$expression}));
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return ( $Var{$expression} )
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if ( defined( $Var{$expression} ) );
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# If it's a numeric literal, simply return it
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if ( $expression =~ m{^-?\d+$} ) {
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@@ -337,8 +351,8 @@ sub parse_expression {
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#printf( "Found the instruction %s: 0%o\n", $word1, $inst{$word1} );
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my $instruction = $inst{$word1};
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# Is this an indirect instruction?
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my $indirect = defined($word3) && ($word3 eq "i") ? 020000 : 0;
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# Is this an indirect instruction?
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my $indirect = defined($word3) && ( $word3 eq "i" ) ? 020000 : 0;
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# We have an expression for this instruction
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if ( ( $stage == 2 ) && defined($word2) ) {
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@@ -380,10 +394,10 @@ sub parse_expression {
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die("Unable to subtract $word1 on pass two\n")
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if ( !defined($diff) );
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}
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#print("Did a subtraction and got $diff\n");
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return ($diff);
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}
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die("I have no idea what $expression is in pass two\n") if ( $stage == 2 );
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}
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@@ -395,6 +409,7 @@ sub add {
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my $val2 = parse_expression($b);
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#print("Adding $val1 + $val2\n");
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return (undef) if ( !defined($val1) || !defined($val2) );
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#print( " with a good value of ", $val1 + $val2, "\n" );
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return ( $val1 + $val2 );
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}
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@@ -407,6 +422,7 @@ sub subtract {
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my $val2 = parse_expression($b);
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#print("Subtracting $val1 - $val2\n");
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return (undef) if ( !defined($val1) || !defined($val2) );
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#print( " with a good value of ", $val1 - $val2, "\n" );
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return ( $val1 - $val2 );
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}
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@@ -11,7 +11,13 @@ main:
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lac d1
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sys write; hello; 7
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" open file fred
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" Test if the assembler can dac into a mid-line label
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lac helloptr
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dac 1f
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lac d1
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sys write; 1:0; 7
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" Try to open file fred
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sys open; fred; 0; 0
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" read 5 words into the buffer from stdin: type in 10 or more characters!
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@@ -42,6 +48,7 @@ out: 0
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" Hello, world\n, two ASCII chars per word
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hello: 0110145; 0154154; 0157054; 040; 0167157; 0162154; 0144012
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helloptr: hello
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" fred as a string, NUL terminated
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fred: 0146162; 0145144; 0
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