diff --git a/sys/arch/i386/conf/BOAT_ANCHOR b/sys/arch/i386/conf/BOAT_ANCHOR
index 997b1c9794f2..ada508f5831f 100644
--- a/sys/arch/i386/conf/BOAT_ANCHOR
+++ b/sys/arch/i386/conf/BOAT_ANCHOR
@@ -1,7 +1,7 @@
 #
 #	BOAT_ANCHOR -- kernel for the 386-20 the gang uses for testing
 #
-#	$Id: BOAT_ANCHOR,v 1.29 1994/03/09 21:22:33 ws Exp $
+#	$Id: BOAT_ANCHOR,v 1.30 1994/03/23 01:25:53 cgd Exp $
 #
 machine		"i386"
 cpu		"I386_CPU"
@@ -37,6 +37,11 @@ device		pc0	at isa? port "IO_KBD" tty irq 1 vector pcrint
 device		npx0	at isa? port "IO_NPX" irq 13 vector npxintr
 
 device          com0    at isa? port "IO_COM1" tty irq 4 vector comintr
+master		ast0	at isa? port 0x1a0 tty irq 3 vector astintr
+device		com1	at ast0 slave 0
+device		com2	at ast0 slave 1
+device		com3	at ast0 slave 2
+device		com4	at ast0 slave 3
 
 device ed0 at isa? port 0x280 net irq 9 iomem 0xd0000 vector edintr
 
diff --git a/sys/arch/i386/isa/ast.c b/sys/arch/i386/isa/ast.c
new file mode 100644
index 000000000000..7101cf758b69
--- /dev/null
+++ b/sys/arch/i386/isa/ast.c
@@ -0,0 +1,89 @@
+/*
+ * Multi-port serial card interrupt demuxing support.
+ * Roland McGrath 3/20/94
+ *
+ *	$Id: ast.c,v 1.1 1994/03/23 01:26:14 cgd Exp $
+ */
+
+#include "ast.h"
+
+#include <sys/types.h>
+
+#include <machine/pio.h>
+#include <i386/isa/isa_device.h>
+
+int astprobe __P((struct isa_device *));
+int astattach __P((struct isa_device *));
+
+struct	isa_driver astdriver = {
+	astprobe, astattach, "ast"
+};
+
+struct astunit			/* XXX ast_softc? */
+{
+	u_short iobase;
+	int alive;		/* Mask of slave units attached. */
+	int slaveunits[8];	/* com device unit numbers. XXX - softc ptrs */
+} astunits[NAST];
+
+int
+astprobe(struct isa_device *isa_dev)
+{
+	/*
+	 * Do the normal com probe for the first UART and assume
+	 * its presence means there is a multiport board there.
+	 * XXX needs more robustness.
+	 */
+	return comprobe1(isa_dev->id_iobase);
+}
+
+int
+astattach(struct isa_device *isa_dev)
+{
+	int unit = isa_dev->id_unit;
+  	u_short iobase = isa_dev->id_iobase;
+	unsigned int x;
+  
+	astunits[unit].iobase = iobase;
+
+	/*
+	 * XXX calculation of master address is a bit hazy --
+	 * what if > 4 ports, etc.
+	 */
+	outb (iobase | 0x1f, 0x80);
+	x = inb (iobase | 0x1f);
+	/*
+	 * My guess is this bitmask tells you how many ports are there.
+	 * I only have a 4-port board to try (returns 0xf). --roland
+	 */
+	printf ("ast%d: 0x%x\n", unit, x);
+}
+
+void
+astslave(struct isa_device *slave, int comunit)
+{
+	struct astunit *a = &astunits[slave->id_parent->id_unit];
+
+	a->slaveunits[slave->id_physid] = comunit;
+	a->alive |= 1 << slave->id_physid;
+}
+
+int
+astintr(int unit)
+{
+	struct astunit *a = &astunits[unit];
+	u_short iobase = a->iobase;
+	int alive = a->alive;
+	int bits;
+
+	do {
+		bits = inb (iobase | 0x1f) & alive;
+#define TRY(I)	((bits & (1 << (I))) ? 0 : comintr (a->slaveunits[I]))
+		TRY (0), TRY (1), TRY (2), TRY (3);
+		/* XXX -- i think the next 4 are bogus, see above -- cgd */
+		TRY (4), TRY (5), TRY (6), TRY (7);
+#undef TRY
+ 	} while (bits != alive);
+
+	return 1;
+}
diff --git a/sys/dev/isa/ast.c b/sys/dev/isa/ast.c
new file mode 100644
index 000000000000..7101cf758b69
--- /dev/null
+++ b/sys/dev/isa/ast.c
@@ -0,0 +1,89 @@
+/*
+ * Multi-port serial card interrupt demuxing support.
+ * Roland McGrath 3/20/94
+ *
+ *	$Id: ast.c,v 1.1 1994/03/23 01:26:14 cgd Exp $
+ */
+
+#include "ast.h"
+
+#include <sys/types.h>
+
+#include <machine/pio.h>
+#include <i386/isa/isa_device.h>
+
+int astprobe __P((struct isa_device *));
+int astattach __P((struct isa_device *));
+
+struct	isa_driver astdriver = {
+	astprobe, astattach, "ast"
+};
+
+struct astunit			/* XXX ast_softc? */
+{
+	u_short iobase;
+	int alive;		/* Mask of slave units attached. */
+	int slaveunits[8];	/* com device unit numbers. XXX - softc ptrs */
+} astunits[NAST];
+
+int
+astprobe(struct isa_device *isa_dev)
+{
+	/*
+	 * Do the normal com probe for the first UART and assume
+	 * its presence means there is a multiport board there.
+	 * XXX needs more robustness.
+	 */
+	return comprobe1(isa_dev->id_iobase);
+}
+
+int
+astattach(struct isa_device *isa_dev)
+{
+	int unit = isa_dev->id_unit;
+  	u_short iobase = isa_dev->id_iobase;
+	unsigned int x;
+  
+	astunits[unit].iobase = iobase;
+
+	/*
+	 * XXX calculation of master address is a bit hazy --
+	 * what if > 4 ports, etc.
+	 */
+	outb (iobase | 0x1f, 0x80);
+	x = inb (iobase | 0x1f);
+	/*
+	 * My guess is this bitmask tells you how many ports are there.
+	 * I only have a 4-port board to try (returns 0xf). --roland
+	 */
+	printf ("ast%d: 0x%x\n", unit, x);
+}
+
+void
+astslave(struct isa_device *slave, int comunit)
+{
+	struct astunit *a = &astunits[slave->id_parent->id_unit];
+
+	a->slaveunits[slave->id_physid] = comunit;
+	a->alive |= 1 << slave->id_physid;
+}
+
+int
+astintr(int unit)
+{
+	struct astunit *a = &astunits[unit];
+	u_short iobase = a->iobase;
+	int alive = a->alive;
+	int bits;
+
+	do {
+		bits = inb (iobase | 0x1f) & alive;
+#define TRY(I)	((bits & (1 << (I))) ? 0 : comintr (a->slaveunits[I]))
+		TRY (0), TRY (1), TRY (2), TRY (3);
+		/* XXX -- i think the next 4 are bogus, see above -- cgd */
+		TRY (4), TRY (5), TRY (6), TRY (7);
+#undef TRY
+ 	} while (bits != alive);
+
+	return 1;
+}