I've commited a change to as7 to use the C pre-processor. Not sure if it's

to everybody's taste.

build/Makefile

@@ -1,6 +1,8 @@
 # Build the kernel, the filesystem and run SimH
+# Put any defines for as7 here
+#DEFINES=
 
-AS=../tools/as7
+AS=../tools/as7 $(DEFINES)
 MKFS=../tools/mkfs7
 SYS=../src/sys
 
@@ -18,7 +20,7 @@ coldboot:
 	$(AS) -f list -o a.lst $(SYS)/sop.s $(SYS)/s[1-9].s
 
 image.fs:
-	$(MKFS) --debug --format simh proto
+	$(MKFS) --format simh proto
 
 clean:
 	rm -f a.rim image.fs a.lst

src/sys/s7.s

@@ -5,26 +5,28 @@ pibreak:			" priority interrupt break processing "chain"
    dac .ac			" save interrupt AC
 	"** CROSSED OUT....
 
-   " dpsf		" Warren commented this code out to try and
-   " jmp 1f		" disable the Graphics-2 I/O
+#ifdef GRAPHICS2
+   dpsf
+   jmp 1f		" disable the Graphics-2 I/O
 
-   " dpcf
-   " dprs
-   " dac dpstat
-   " sma ral
-   " jmp 2f
-   " dprc
-   " dac dpchar
-   " -1
-   " dac dpread
-   " lac dpstat
-   " ral
-" 2:
-   " sma
-   " jmp piret
-   " -1
-   " dac dpwrite
-   " jmp piret	"** END OF CROSSOUT
+   dpcf
+   dprs
+   dac dpstat
+   sma ral
+   jmp 2f
+   dprc
+   dac dpchar
+   -1
+   dac dpread
+   lac dpstat
+   ral
+2:
+   sma
+   jmp piret
+   -1
+   dac dpwrite
+   jmp piret	"** END OF CROSSOUT
+#endif
 
 1: clsf			" clock overflow (line frequency ticks)?
    jmp 1f		"  no
@@ -88,26 +90,26 @@ cnop:			" fetched as constant in iread
    dac .dspb
    jmp piret
 dsprestart:
-			" Warren commented this out to try and
-			" disable the Graphics-2 I/O
-   " lac d1
-   " dac .dspb			" set .dsbp = 1
-   " lac dspbufp			" load display buf pointer
-   " beg				" start display processor
-   " -10
-   " dac .dsptm			" set .dsptm = -10 (10 ticks)
-   " jmp piret
+#ifdef GRAPHICS2
+   lac d1
+   dac .dspb			" set .dsbp = 1
+   lac dspbufp			" load display buf pointer
+   beg				" start display processor
+   -10
+   dac .dsptm			" set .dsptm = -10 (10 ticks)
+   jmp piret
 
-" 1: sna ral			" dataphone flag set (bit 7)??
-   " jmp .+3			"  no
-   " raef				" XXX: fix comment
-   " jmp piret			" return
-   " sma				" light pen flags (bit 2)
-   " jmp 1f			"  no
-   " lda				" G-2: load display address
-   " dac .lpba			" save
-   " rlpd				" G-2: resume after light pen stop
-   " jmp piret
+1: sna ral			" dataphone flag set (bit 7)??
+   jmp .+3			"  no
+   raef				" XXX: fix comment
+   jmp piret			" return
+   sma				" light pen flags (bit 2)
+   jmp 1f			"  no
+   lda				" G-2: load display address
+   dac .lpba			" save
+   rlpd				" G-2: resume after light pen stop
+   jmp piret
+#endif
 
 1: ksf				" (TTY) keyboard flag set?
    jmp 1f			"  no

tools/as7

@@ -38,10 +38,13 @@ my $debug = 0;		# Run in debug mode
 my $format = 'a7out';	# output format
 my $namelist = 0;	# output n.out file
 my $output = 'a.out';	# output file
+my @cppdefs;		# C pre-processor defines
+my @cppundefs;		# C pre-processor undefines
 
 # keep this near the GetOptions call to make it easy to add documentation!
 sub usage {
-    die("Usage: $0 [--debug] [--format=a7out|list|ptr|rim ] [--out file] file1.s [file2.s ...]\n")
+    die("Usage: $0 [-Dmacro] [-Umacro] [--debug] [--format=a7out|list|ptr|rim ]\n" .	
+	"\t[--out file] file1.s [file2.s ...]\n");
 }
 
 GetOptions(
@@ -49,6 +52,8 @@ GetOptions(
     'format|f=s' => \$format,
     'namelist|n' => \$namelist,
     'output|o=s' => \$output,
+    'D|D=s' => \@cppdefs,
+    'U|U=s' => \@cppundefs,
 ) or usage();
 
 usage() if ( @ARGV < 1 );
@@ -265,9 +270,18 @@ sub err {
 # Open and parse the given file
 sub parse_file {
     $file = shift;
-    open( my $IN, "<", $file ) || die("Cannot read $file: $!\n");
+
+    # Get the C pre-processor command-line arguments
+    my $defines= join(' ', map { "-D$_" } @cppdefs) || "";
+    my $undefines= join(' ', map { "-U$_" } @cppundefs) || "";
+  
+    open( my $IN, "-|", "cpp -trigraphs $defines $undefines $file" )
+				|| die("Cannot pipe cpp $file: $!\n");
     $lineno = 0;
     while ( $line = <$IN> ) {
+	# Lose any C pre-processor comment lines
+	next if ($line=~ m{^#});
+
 	$lineno++;
         chomp($line);		# Lose the end of line
         $origline = $line;