Initial source

17 files changed, 1229 insertions, 0 deletions

diff --git a/i386/pc/i16/i16_a20.c b/i386/pc/i16/i16_a20.c
new file mode 100644
index 0000000..5e91f86
--- /dev/null
+++ b/i386/pc/i16/i16_a20.c
@@ -0,0 +1,144 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+
+#include <mach/machine/pio.h>
+#include <mach/machine/code16.h>
+
+#include "i16_a20.h"
+
+
+/* Keyboard stuff for turning on the A20 address line (gak!).  */
+#define K_RDWR 		0x60		/* keyboard data & cmds (read/write) */
+#define K_STATUS 	0x64		/* keyboard status (read-only) */
+#define K_CMD	 	0x64		/* keybd ctlr command (write-only) */
+
+#define K_OBUF_FUL 	0x01		/* output buffer full */
+#define K_IBUF_FUL 	0x02		/* input buffer full */
+
+#define KC_CMD_WIN	0xd0		/* read  output port */
+#define KC_CMD_WOUT	0xd1		/* write output port */
+
+#define KB_ENABLE_A20	0xdf	/* Linux and my BIOS uses this,
+				   and I trust them more than Mach 3.0,
+				   but I'd like to know what the difference is
+				   and if it matters.  */
+			/*0x9f*/	/* enable A20,
+					   enable output buffer full interrupt
+					   enable data line
+					   disable clock line */
+#define KB_DISABLE_A20	0xdd
+
+
+CODE16
+
+
+/*
+   This routine ensures that the keyboard command queue is empty
+   (after emptying the output buffers)
+
+   No timeout is used - if this hangs there is something wrong with
+   the machine, and we probably couldn't proceed anyway.
+   XXX should at least die properly
+*/
+static void i16_empty_8042(void)
+{
+	int status;
+
+retry:
+	i16_nanodelay(1000);
+	status = i16_inb(K_STATUS);
+
+	if (status & K_OBUF_FUL)
+	{
+		i16_nanodelay(1000);
+		i16_inb(K_RDWR);
+		goto retry;
+	}
+
+	if (status & K_IBUF_FUL)
+		goto retry;
+}
+
+int i16_raw_test_a20(void);
+
+/* Enable the A20 address line.  */
+void i16_raw_enable_a20(void)
+{
+	int v;
+
+	/* XXX try int 15h function 24h */
+
+	if (i16_raw_test_a20())
+		return;
+
+	/* PS/2 */
+	v = i16_inb(0x92);
+	i16_nanodelay(1000);
+	i16_outb(0x92,v | 2);
+
+	if (i16_raw_test_a20())
+		return;
+
+	/* AT */
+	i16_empty_8042();
+	i16_outb(K_CMD, KC_CMD_WOUT);
+	i16_empty_8042();
+	i16_outb(K_RDWR, KB_ENABLE_A20);
+	i16_empty_8042();
+
+	/* Wait until the a20 line gets enabled.  */
+	while (!i16_raw_test_a20());
+}
+
+/* Disable the A20 address line.  */
+void i16_raw_disable_a20(void)
+{
+	int v;
+
+	if (!i16_raw_test_a20())
+		return;
+
+	/* PS/2 */
+	v = i16_inb(0x92);
+	i16_nanodelay(1000);
+	i16_outb(0x92, v & ~2);
+
+	if (!i16_raw_test_a20())
+		return;
+
+	/* AT */
+	i16_empty_8042();
+	i16_outb(K_CMD, KC_CMD_WOUT);
+	i16_empty_8042();
+	i16_outb(K_RDWR, KB_DISABLE_A20);
+	i16_empty_8042();
+
+	/* Wait until the a20 line gets disabled.  */
+	while (i16_raw_test_a20());
+}
+
+
+void (*i16_enable_a20)(void) = i16_raw_enable_a20;
+void (*i16_disable_a20)(void) = i16_raw_disable_a20;
+
diff --git a/i386/pc/i16/i16_a20.h b/i386/pc/i16/i16_a20.h
new file mode 100644
index 0000000..afe124b
--- /dev/null
+++ b/i386/pc/i16/i16_a20.h
@@ -0,0 +1,32 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+#ifndef _I386_PC_A20_H_
+#define _I386_PC_A20_H_
+
+/* By default these point to the "raw" routines in pc/a20.c.
+   They can be revectored to other routines,
+   e.g. to use a HIMEM driver's facilities.  */
+extern void (*i16_enable_a20)(void);
+extern void (*i16_disable_a20)(void);
+
+#endif _I386_PC_A20_H_
diff --git a/i386/pc/i16/i16_bios.h b/i386/pc/i16/i16_bios.h
new file mode 100644
index 0000000..29dc2d8
--- /dev/null
+++ b/i386/pc/i16/i16_bios.h
@@ -0,0 +1,98 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+#ifndef _I16_BIOS_H_
+#define _I16_BIOS_H_
+
+#include <mach/inline.h>
+
+
+MACH_INLINE void i16_bios_putchar(int c)
+{
+	asm volatile("int $0x10" : : "a" (0x0e00 | (c & 0xff)), "b" (0x07));
+}
+
+MACH_INLINE int i16_bios_getchar()
+{
+	int c;
+	asm volatile("int $0x16" : "=a" (c) : "a" (0x0000));
+	c &= 0xff;
+	return c;
+}
+
+MACH_INLINE void i16_bios_warm_boot(void)
+{
+	asm volatile("
+		cli
+		movw	$0x40,%ax
+		movw	%ax,%ds
+		movw	$0x1234,0x72
+		ljmp	$0xffff,$0x0000
+	");
+}
+
+MACH_INLINE void i16_bios_cold_boot(void)
+{
+	asm volatile("
+		cli
+		movw	$0x40,%ax
+		movw	%ax,%ds
+		movw	$0x0000,0x72
+		ljmp	$0xffff,$0x0000
+	");
+}
+
+MACH_INLINE unsigned char i16_bios_copy_ext_mem(
+	unsigned src_la, unsigned dest_la, unsigned short word_count)
+{
+	char buf[48];
+	unsigned short i, rc;
+
+	/* Initialize the descriptor structure.  */
+	for (i = 0; i < sizeof(buf); i++)
+		buf[i] = 0;
+	*((unsigned short*)(buf+0x10)) = 0xffff; /* source limit */
+	*((unsigned long*)(buf+0x12)) = src_la; /* source linear address */
+	*((unsigned char*)(buf+0x15)) = 0x93; /* source access rights */
+	*((unsigned short*)(buf+0x18)) = 0xffff; /* dest limit */
+	*((unsigned long*)(buf+0x1a)) = dest_la; /* dest linear address */
+	*((unsigned char*)(buf+0x1d)) = 0x93; /* dest access rights */
+
+#if 0
+	i16_puts("buf:");
+	for (i = 0; i < sizeof(buf); i++)
+		i16_writehexb(buf[i]);
+	i16_puts("");
+#endif
+
+	/* Make the BIOS call to perform the copy.  */
+	asm volatile("
+		int	$0x15
+	" : "=a" (rc)
+	  : "a" ((unsigned short)0x8700),
+	    "c" (word_count),
+	    "S" ((unsigned short)(unsigned)buf));
+
+	return rc >> 8;
+}
+
+#endif _I16_BIOS_H_
diff --git a/i386/pc/i16/i16_exit.c b/i386/pc/i16/i16_exit.c
new file mode 100644
index 0000000..674033a
--- /dev/null
+++ b/i386/pc/i16/i16_exit.c
@@ -0,0 +1,37 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/code16.h>
+
+#include "i16_bios.h"
+
+
+CODE16
+
+void i16_exit(int rc)
+{
+	i16_puts("Press any key to reboot.");
+	i16_bios_getchar();
+	i16_bios_warm_boot();
+}
+
diff --git a/i386/pc/i16/i16_ext_mem.c b/i386/pc/i16/i16_ext_mem.c
new file mode 100644
index 0000000..08cbecf
--- /dev/null
+++ b/i386/pc/i16/i16_ext_mem.c
@@ -0,0 +1,151 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/code16.h>
+#include <mach/machine/vm_types.h>
+#include <mach/machine/far_ptr.h>
+#include <mach/machine/proc_reg.h>
+
+#include "i16_bios.h"
+#include "phys_mem.h"
+#include "vm_param.h"
+#include "debug.h"
+
+
+static vm_offset_t ext_mem_phys_free_mem;
+static vm_size_t ext_mem_phys_free_size;
+
+
+CODE32
+
+int ext_mem_collect(void)
+{
+	if (ext_mem_phys_free_mem)
+	{
+		phys_mem_add(ext_mem_phys_free_mem, ext_mem_phys_free_size);
+		ext_mem_phys_free_mem = 0;
+	}
+}
+
+CODE16
+
+void i16_ext_mem_check()
+{
+	vm_offset_t ext_mem_top, ext_mem_bot;
+	unsigned short ext_mem_k;
+
+	/* Find the top of available extended memory.  */
+	asm volatile("
+		int	$0x15
+		jnc	1f
+		xorw	%%ax,%%ax
+	1:
+	" : "=a" (ext_mem_k)
+	  : "a" (0x8800));
+	ext_mem_top = 0x100000 + (vm_offset_t)ext_mem_k * 1024;
+
+	/* XXX check for >16MB memory using function 0xc7 */
+
+	ext_mem_bot = 0x100000;
+
+	/* Check for extended memory allocated bottom-up: method 1.
+	   This uses the technique (and, loosely, the code)
+	   described in the VCPI spec, version 1.0.  */
+	if (ext_mem_top > ext_mem_bot)
+	{
+		asm volatile("
+			pushw	%%es
+
+			xorw	%%ax,%%ax
+			movw	%%ax,%%es
+			movw	%%es:0x19*4+2,%%ax
+			movw	%%ax,%%es
+
+			movw	$0x12,%%di
+			movw	$7,%%cx
+			rep
+			cmpsb
+			jne	1f
+
+			xorl	%%edx,%%edx
+			movb	%%es:0x2e,%%dl
+			shll	$16,%%edx
+			movw	%%es:0x2c,%%dx
+
+		1:
+			popw	%%es
+		" : "=d" (ext_mem_bot)
+		  : "d" (ext_mem_bot),
+		    "S" ((unsigned short)(vm_offset_t)"VDISK V")
+		  : "eax", "ecx", "esi", "edi");
+	}
+	i16_assert(ext_mem_bot >= 0x100000);
+
+	/* Check for extended memory allocated bottom-up: method 2.
+	   This uses the technique (and, loosely, the code)
+	   described in the VCPI spec, version 1.0.  */
+	if (ext_mem_top > ext_mem_bot)
+	{
+		struct {
+			char pad1[3];
+			char V;
+			long DISK;
+			char pad2[30-8];
+			unsigned short addr;
+		} buf;
+		unsigned char rc;
+
+		i16_assert(sizeof(buf) == 0x20);
+		rc = i16_bios_copy_ext_mem(0x100000, kvtolin((vm_offset_t)&buf), sizeof(buf)/2);
+		if ((rc == 0) && (buf.V == 'V') && (buf.DISK == 'DISK'))
+		{
+			vm_offset_t new_bot = (vm_offset_t)buf.addr << 10;
+			i16_assert(new_bot > 0x100000);
+			if (new_bot > ext_mem_bot)
+				ext_mem_bot = new_bot;
+		}
+	}
+	i16_assert(ext_mem_bot >= 0x100000);
+
+	if (ext_mem_top > ext_mem_bot)
+	{
+		ext_mem_phys_free_mem = ext_mem_bot;
+		ext_mem_phys_free_size = ext_mem_top - ext_mem_bot;
+
+		/* We need to update phys_mem_max here
+		   instead of just letting phys_mem_add() do it
+		   when the memory is collected with phys_mem_collect(),
+		   because VCPI initialization needs to know the top of physical memory
+		   before phys_mem_collect() is called.
+		   See i16_vcpi.c for the gross details.  */
+		if (ext_mem_top > phys_mem_max)
+			phys_mem_max = ext_mem_top;
+	}
+}
+
+void i16_ext_mem_shutdown()
+{
+	/* We didn't actually allocate the memory,
+	   so no need to deallocate it... */
+}
+
diff --git a/i386/pc/i16/i16_init.c b/i386/pc/i16/i16_init.c
new file mode 100644
index 0000000..23a51df
--- /dev/null
+++ b/i386/pc/i16/i16_init.c
@@ -0,0 +1,67 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/code16.h>
+#include <mach/machine/proc_reg.h>
+
+#include "vm_param.h"
+
+
+/* Code segment we originally had when we started in real mode.  */
+unsigned short real_cs;
+
+/* Virtual address of physical memory.  */
+vm_offset_t phys_mem_va;
+
+/* Physical address of start of boot image.  */
+vm_offset_t boot_image_pa;
+
+/* Upper limit of known physical memory.  */
+vm_offset_t phys_mem_max;
+
+
+CODE16
+
+#include "i16_bios.h"
+
+/* Called by i16_crt0 (or the equivalent)
+   to set up our basic 16-bit runtime environment
+   before calling i16_main().  */
+void i16_init(void)
+{
+	/* Find our code/data/everything segment.  */
+	real_cs = get_cs();
+
+	/* Find out where in physical memory we got loaded.  */
+	boot_image_pa = real_cs << 4;
+
+	/* Find out where the bottom of physical memory is.
+	   (We won't be able to directly use it for 32-bit accesses
+	   until we actually get into 32-bit mode.)  */
+	phys_mem_va = -boot_image_pa;
+
+	/* The base of linear memory is at the same place,
+	   at least until we turn paging on.  */
+	linear_base_va = phys_mem_va;
+}
+
diff --git a/i386/pc/i16/i16_main.c b/i386/pc/i16/i16_main.c
new file mode 100644
index 0000000..328cceb
--- /dev/null
+++ b/i386/pc/i16/i16_main.c
@@ -0,0 +1,38 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/code16.h>
+
+
+CODE16
+
+void i16_main(void)
+{
+	i16_init();
+
+	/* Grab all the memory we can find.  */
+	i16_ext_mem_check();
+
+	i16_raw_start();
+}
+
diff --git a/i386/pc/i16/i16_pic.c b/i386/pc/i16/i16_pic.c
new file mode 100644
index 0000000..3ff2697
--- /dev/null
+++ b/i386/pc/i16/i16_pic.c
@@ -0,0 +1,66 @@
+/* 
+ * Copyright (c) 1995 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/pio.h>
+
+#include "pic.h"
+#include "i16.h"
+
+CODE16
+
+/* Program the PICs to use a different set of interrupt vectors.
+   Assumes processor I flag is off.  */
+void i16_pic_set_master(int base)
+{
+	unsigned char old_mask;
+
+	/* Save the original interrupt mask.  */
+	old_mask = inb(MASTER_OCW);	PIC_DELAY();
+
+	/* Initialize the master PIC.  */
+	outb(MASTER_ICW, PICM_ICW1);	PIC_DELAY();
+	outb(MASTER_OCW, base);		PIC_DELAY();
+	outb(MASTER_OCW, PICM_ICW3);	PIC_DELAY();
+	outb(MASTER_OCW, PICM_ICW4);	PIC_DELAY();
+
+	/* Restore the original interrupt mask.  */
+	outb(MASTER_OCW, old_mask);	PIC_DELAY();
+}
+
+void i16_pic_set_slave(int base)
+{
+	unsigned char old_mask;
+
+	/* Save the original interrupt mask.  */
+	old_mask = inb(SLAVES_OCW);	PIC_DELAY();
+
+	/* Initialize the slave PIC.  */
+	outb(SLAVES_ICW, PICS_ICW1);	PIC_DELAY();
+	outb(SLAVES_OCW, base);		PIC_DELAY();
+	outb(SLAVES_OCW, PICS_ICW3);	PIC_DELAY();
+	outb(SLAVES_OCW, PICS_ICW4);	PIC_DELAY();
+
+	/* Restore the original interrupt mask.  */
+	outb(SLAVES_OCW, old_mask);	PIC_DELAY();
+}
+
diff --git a/i386/pc/i16/i16_putchar.c b/i386/pc/i16/i16_putchar.c
new file mode 100644
index 0000000..365f4f8
--- /dev/null
+++ b/i386/pc/i16/i16_putchar.c
@@ -0,0 +1,36 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/code16.h>
+
+#include "i16_bios.h"
+
+CODE16
+
+void i16_putchar(int ch)
+{
+	if (ch == '\n')
+		i16_bios_putchar('\r');
+	i16_bios_putchar(ch);
+}
+
diff --git a/i386/pc/i16/i16_raw.c b/i386/pc/i16/i16_raw.c
new file mode 100644
index 0000000..1f705d3
--- /dev/null
+++ b/i386/pc/i16/i16_raw.c
@@ -0,0 +1,265 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+/*
+	This file rovides a default implementation
+	of real/pmode switching code.
+	Assumes that, as far as it's concerned,
+	low linear address always map to physical addresses.
+	(The low linear mappings can be changed,
+	but must be changed back before switching back to real mode.)
+
+	Provides:
+		i16_raw_switch_to_pmode()
+		i16_raw_switch_to_real_mode()
+
+		i16_raw_start()
+			Called in real mode.
+			Initializes the pmode switching system,
+			switches to pmode for the first time,
+			and calls the 32-bit function raw_start().
+
+	Depends on:
+
+		paging.h:
+			raw_paging_enable()
+			raw_paging_disable()
+			raw_paging_init()
+
+		a20.h:
+			i16_enable_a20()
+			i16_disable_a20()
+
+		real.h:
+			real_cs
+*/
+
+#include <mach/boolean.h>
+#include <mach/machine/code16.h>
+#include <mach/machine/vm_param.h>
+#include <mach/machine/proc_reg.h>
+#include <mach/machine/pio.h>
+#include <mach/machine/seg.h>
+#include <mach/machine/eflags.h>
+#include <mach/machine/pmode.h>
+
+#include "config.h"
+#include "cpu.h"
+#include "i16.h"
+#include "vm_param.h"
+#include "pic.h"
+#include "debug.h"
+#include "i16_a20.h"
+#include "i16_switch.h"
+
+int irq_master_base, irq_slave_base;
+
+/* Set to true when everything is initialized properly.  */
+static boolean_t inited;
+
+/* Saved value of eflags register for real mode.  */
+static unsigned real_eflags;
+
+
+
+#ifdef ENABLE_PAGING
+#define RAW_PAGING_ENABLE() raw_paging_enable()
+#define RAW_PAGING_DISABLE() raw_paging_disable()
+#define RAW_PAGING_INIT() raw_paging_init()
+#else
+#define RAW_PAGING_ENABLE() ((void)0)
+#define RAW_PAGING_DISABLE() ((void)0)
+#define RAW_PAGING_INIT() ((void)0)
+#endif
+
+
+CODE16
+
+void i16_raw_switch_to_pmode()
+{
+	/* No interrupts from now on please.  */
+	i16_cli();
+
+	/* Save the eflags register for switching back later.  */
+	real_eflags = get_eflags();
+
+	/* Enable the A20 address line.  */
+	i16_enable_a20();
+
+	/* Load the GDT.
+	   Note that we have to do this each time we enter pmode,
+	   not just the first,
+	   because other real-mode programs may have switched to pmode
+	   and back again in the meantime, trashing the GDT pointer.  */
+	{
+		struct pseudo_descriptor pdesc;
+
+		pdesc.limit = sizeof(cpu[0].tables.gdt)-1;
+		pdesc.linear_base = boot_image_pa
+				    + (vm_offset_t)&cpu[0].tables.gdt;
+		i16_set_gdt(&pdesc);
+	}
+
+	/* Switch into protected mode.  */
+	i16_enter_pmode(KERNEL_16_CS);
+
+	/* Reload all the segment registers from the new GDT.  */
+	set_ds(KERNEL_DS);
+	set_es(KERNEL_DS);
+	set_fs(0);
+	set_gs(0);
+	set_ss(KERNEL_DS);
+
+	i16_do_32bit(
+
+		if (inited)
+		{
+			/* Turn paging on if necessary.  */
+			RAW_PAGING_ENABLE();
+
+			/* Load the CPU tables into the processor.  */
+			cpu_tables_load(&cpu[0]);
+
+			/* Program the PIC so the interrupt vectors won't
+			   conflict with the processor exception vectors.  */
+			pic_init(PICM_VECTBASE, PICS_VECTBASE);
+		}
+
+		/* Make sure our flags register is appropriate.  */
+		set_eflags((get_eflags()
+			   & ~(EFL_IF | EFL_DF | EFL_NT))
+			   | EFL_IOPL_USER);
+	);
+}
+
+void i16_raw_switch_to_real_mode()
+{
+	/* Make sure interrupts are disabled.  */
+	cli();
+
+	/* Avoid sending DOS bogus coprocessor exceptions.
+	   XXX should we save/restore all of CR0?  */
+	i16_clts();
+
+	i16_do_32bit(
+		/* Turn paging off if necessary.  */
+		RAW_PAGING_DISABLE();
+
+		/* Reprogram the PIC back to the settings DOS expects.  */
+		pic_init(0x08, 0x70);
+	);
+
+	/* Make sure all the segment registers are 16-bit.
+	   The code segment definitely is already,
+	   because we're running 16-bit code.  */
+	set_ds(KERNEL_16_DS);
+	set_es(KERNEL_16_DS);
+	set_fs(KERNEL_16_DS);
+	set_gs(KERNEL_16_DS);
+	set_ss(KERNEL_16_DS);
+
+	/* Switch back to real mode.  */
+	i16_leave_pmode(real_cs);
+
+	/* Load the real-mode segment registers.  */
+	set_ds(real_cs);
+	set_es(real_cs);
+	set_fs(real_cs);
+	set_gs(real_cs);
+	set_ss(real_cs);
+
+	/* Load the real-mode IDT.  */
+	{
+		struct pseudo_descriptor pdesc;
+
+		pdesc.limit = 0xffff;
+		pdesc.linear_base = 0;
+		i16_set_idt(&pdesc);
+	}
+
+	/* Disable the A20 address line.  */
+	i16_disable_a20();
+
+	/* Restore the eflags register to its original real-mode state.
+	   Note that this will leave interrupts disabled
+	   since it was saved after the cli() above.  */
+	set_eflags(real_eflags);
+}
+
+void i16_raw_start()
+{
+	/* Make sure we're not already in protected mode.  */
+	if (i16_get_msw() & CR0_PE)
+		i16_die("The processor is in an unknown "
+			"protected mode environment.");
+
+	do_debug(i16_puts("Real mode detected"));
+
+	/* Minimally initialize the GDT.  */
+	i16_gdt_init_temp();
+
+	/* Switch to protected mode for the first time.
+	   This won't load all the processor tables and everything yet,
+	   since they're not fully initialized.  */
+	i16_raw_switch_to_pmode();
+
+	/* We can now hop in and out of 32-bit mode at will.  */
+	i16_do_32bit(
+
+		/* Now that we can access all physical memory,
+		   collect the memory regions we discovered while in 16-bit mode
+		   and add them to our free memory list.
+		   We can't do this before now because the free list nodes
+		   are stored in the free memory itself,
+		   which is probably out of reach of our 16-bit segments.  */
+		phys_mem_collect();
+
+		/* Initialize paging if necessary.
+		   Do it before initializing the other processor tables
+		   because they might have to be located
+		   somewhere in high linear memory.  */
+		RAW_PAGING_INIT();
+
+		/* Initialize the processor tables.  */
+		cpu_init(&cpu[0]);
+
+		/* Initialize the hardware interrupt vectors in the IDT.  */
+		irq_master_base = PICM_VECTBASE;
+		irq_slave_base = PICS_VECTBASE;
+		idt_irq_init();
+
+		inited = TRUE;
+
+		/* Switch to real mode and back again once more,
+		   to make sure everything's loaded properly.  */
+		do_16bit(
+			i16_raw_switch_to_real_mode();
+			i16_raw_switch_to_pmode();
+		);
+
+		raw_start();
+	);
+}
+
+void (*i16_switch_to_real_mode)() = i16_raw_switch_to_real_mode;
+void (*i16_switch_to_pmode)() = i16_raw_switch_to_pmode;
+
diff --git a/i386/pc/i16/i16_raw_test_a20.S b/i386/pc/i16/i16_raw_test_a20.S
new file mode 100644
index 0000000..a934e12
--- /dev/null
+++ b/i386/pc/i16/i16_raw_test_a20.S
@@ -0,0 +1,35 @@
+
+#include <mach/machine/asm.h>
+
+	.text
+	.code16
+
+/*
+ * Test the A20 address line; return true if it is enabled.
+ */
+ENTRY(i16_raw_test_a20)
+	xorw	%ax,%ax
+	movw	%ax,%fs
+	notw	%ax
+	movw	%ax,%gs
+
+	/* See if the values in already in the corresponding locations
+	   are the same.  */
+	movw	%fs:0,%ax
+	cmpw	%gs:16,%ax
+	jnz	1f
+
+	/* Yes; try changing one and see if they're still the same.  */
+	movw	%ax,%dx
+	notw	%ax
+	movw	%ax,%fs:0
+	cmpw	%gs:16,%ax
+	movw	%dx,%fs:0
+	jnz	1f
+
+	xorl	%eax,%eax
+	ret
+1:
+	movl	$1,%eax
+	ret
+
diff --git a/i386/pc/i16/i16_real_int.S b/i386/pc/i16/i16_real_int.S
new file mode 100644
index 0000000..f05077e
--- /dev/null
+++ b/i386/pc/i16/i16_real_int.S
@@ -0,0 +1,84 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/asm.h>
+
+#include "pc_asm.h"
+
+	.text
+	.code16
+
+ENTRY(i16_real_int)
+	pushf
+	pushl	%ebx
+	pushl	%esi
+	pushl	%edi
+	pushl	%ebp
+
+	cli
+
+	movl	6*4(%esp),%eax
+	movb	%al,1f+1
+
+	movl	7*4(%esp),%ebp
+	movl	RCD_EAX(%ebp),%eax
+	movl	RCD_EBX(%ebp),%ebx
+	movl	RCD_ECX(%ebp),%ecx
+	movl	RCD_EDX(%ebp),%edx
+	movl	RCD_ESI(%ebp),%esi
+	movl	RCD_EDI(%ebp),%edi
+	movw	RCD_DS(%ebp),%ds
+	movw	RCD_ES(%ebp),%es
+	/* XXX flags */
+	movl	RCD_EBP(%ebp),%ebp
+
+1:	int	$0
+
+	pushl	%ebp
+	movl	8*4(%esp),%ebp
+	popl	RCD_EBP(%ebp)
+
+	movl	%eax,RCD_EAX(%ebp)
+	movl	%ebx,RCD_EBX(%ebp)
+	movl	%ecx,RCD_ECX(%ebp)
+	movl	%edx,RCD_EDX(%ebp)
+	movl	%esi,RCD_ESI(%ebp)
+	movl	%edi,RCD_EDI(%ebp)
+	movw	%ds,RCD_DS(%ebp)
+	movw	%es,RCD_ES(%ebp)
+
+	pushf
+	popl	%eax
+	movw	%ax,RCD_FLAGS(%ebp)
+
+	movw	%ss,%ax
+	movw	%ax,%ds
+	movw	%ax,%es
+
+	popl	%ebp
+	popl	%edi
+	popl	%esi
+	popl	%ebx
+	popf
+	ret
+
diff --git a/i386/pc/i16/i16_switch.h b/i386/pc/i16/i16_switch.h
new file mode 100644
index 0000000..b7ecf18
--- /dev/null
+++ b/i386/pc/i16/i16_switch.h
@@ -0,0 +1,30 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+#ifndef _I386_PC_SWITCH_H_
+#define _I386_PC_SWITCH_H_
+
+/* Vectors to routines to switch between real and protected mode.  */
+extern void (*i16_switch_to_real_mode)();
+extern void (*i16_switch_to_pmode)();
+
+#endif _I386_PC_SWITCH_H_
diff --git a/i386/pc/i16/phys_mem_collect.c b/i386/pc/i16/phys_mem_collect.c
new file mode 100644
index 0000000..bcb0c09
--- /dev/null
+++ b/i386/pc/i16/phys_mem_collect.c
@@ -0,0 +1,34 @@
+/* 
+ * Copyright (c) 1995 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/vm_param.h>
+
+#include "phys_mem.h"
+
+void phys_mem_collect(void)
+{
+#define pms(name) name##_collect();
+#include "phys_mem_sources.h"
+#undef pms
+}
+
diff --git a/i386/pc/i16/phys_mem_sources.h b/i386/pc/i16/phys_mem_sources.h
new file mode 100644
index 0000000..788910d
--- /dev/null
+++ b/i386/pc/i16/phys_mem_sources.h
@@ -0,0 +1,25 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+pms(ext_mem)
+
diff --git a/i386/pc/i16/raw_exit.c b/i386/pc/i16/raw_exit.c
new file mode 100644
index 0000000..5ccb69a
--- /dev/null
+++ b/i386/pc/i16/raw_exit.c
@@ -0,0 +1,41 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/seg.h>
+#include <mach/machine/proc_reg.h>
+
+#include "i16.h"
+#include "debug.h"
+
+
+void raw_exit(int rc)
+{
+	do_16bit(
+		i16_raw_switch_to_real_mode();
+		i16_exit(rc);
+		while (1);
+	);
+}
+
+void (*real_exit)(int rc) = raw_exit;
+
diff --git a/i386/pc/i16/raw_real_int.c b/i386/pc/i16/raw_real_int.c
new file mode 100644
index 0000000..a76d8ca
--- /dev/null
+++ b/i386/pc/i16/raw_real_int.c
@@ -0,0 +1,46 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/seg.h>
+#include <mach/machine/proc_reg.h>
+
+#include "real.h"
+#include "i16.h"
+#include "debug.h"
+
+
+void raw_real_int(int intnum, struct real_call_data *rcd)
+{
+	assert((get_cs() & 3) == 0);
+
+	do_16bit(
+		unsigned int eflags;
+
+		i16_raw_switch_to_real_mode();
+		i16_real_int(intnum, rcd);
+		i16_raw_switch_to_pmode();
+	);
+}
+
+void (*real_int)(int intnum, struct real_call_data *rcd) = raw_real_int;
+