Change from '#' to "//" comment character to allow CPP preprocessing.

Merge boot0.s and boot0sio.s into boot0_512.s controlled by "#ifdef SIO".

Add Makefile magic to generate boot0.s and boot0sio.s from boot0_512.s.

The compile boot0 and boot0sio have unchanged MD5 checksums.

5 files changed, 500 insertions, 1295 deletions

diff --git a/sys/boot/i386/boot0/Makefile b/sys/boot/i386/boot0/Makefile
index b8a5e64..a87526f 100644
--- a/sys/boot/i386/boot0/Makefile
+++ b/sys/boot/i386/boot0/Makefile
@@ -36,3 +36,9 @@ AFLAGS+=--defsym FLAGS=${BOOT_BOOT0_FLAGS} \
 LDFLAGS=-N -e start -Ttext ${BOOT_BOOT0_ORG} -Wl,-S,--oformat,binary
 
 .include <bsd.prog.mk>
+
+boot0.s:	boot0_512.s
+	cpp -USIO < ${.CURDIR}/boot0_512.s > boot0.s
+
+boot0sio.s:	${.CURDIR}/../boot0/boot0_512.s
+	cpp -DSIO < ${.CURDIR}/../boot0/boot0_512.s > boot0sio.s
diff --git a/sys/boot/i386/boot0/boot0.S b/sys/boot/i386/boot0/boot0.S
deleted file mode 100644
index 62e6556..0000000
--- a/sys/boot/i386/boot0/boot0.S
+++ /dev/null
@@ -1,438 +0,0 @@
-#
-# Copyright (c) 2002 Bruce M. Simpson
-# Copyright (c) 1998 Robert Nordier
-# All rights reserved.
-#
-# Redistribution and use in source and binary forms are freely
-# permitted provided that the above copyright notice and this
-# paragraph and the following disclaimer are duplicated in all
-# such forms.
-#
-# This software is provided "AS IS" and without any express or
-# implied warranties, including, without limitation, the implied
-# warranties of merchantability and fitness for a particular
-# purpose.
-#
-
-# $FreeBSD$
-
-# A 512-byte boot manager which uses a serial console on COM1.
-
-		.set NHRDRV,0x475		# Number of hard drives
-		.set ORIGIN,0x600		# Execution address
-		.set FAKE,0x800 		# Partition entry
-		.set LOAD,0x7c00		# Load address
-
-		.set PRT_OFF,0x1be		# Partition table
-
-		.set TBL0SZ,0x3 		# Table 0 size
-		.set TBL1SZ,0xb 		# Table 1 size
-
-		.set MAGIC,0xaa55		# Magic: bootable
-		.set B0MAGIC,0xbb66		# Identification
-
-		.set KEY_ENTER,0x1c		# Enter key scan code
-		.set KEY_F1,0x3b		# F1 key scan code
-		.set KEY_1,0x02			# #1 key scan code
-
-		.set ASCII_BEL,0x07		# ASCII code for <BEL>
-		.set ASCII_CR,0x0D		# ASCII code for <CR>
-		.set ASCII_1,0x31		# ASCII code for '1'
-
-#
-# Addresses in the sector of embedded data values.
-# Accessed with negative offsets from the end of the relocated sector (%ebp).
-#
-		.set _NXTDRV,-0x48		# Next drive
-		.set _OPT,-0x47 		# Default option
-		.set _SETDRV,-0x46		# Drive to force
-		.set _FLAGS,-0x45		# Flags
-		.set _TICKS,-0x44		# Timeout ticks
-		.set _FAKE,0x0			# Fake partition entry
-		.set _MNUOPT,0xc		# Menu options
-
-		.globl start			# Entry point
-		.code16				# This runs in real mode
-
-#
-# Initialise segments and registers to known values.
-# segments start at 0.
-# The stack is immediately below the address we were loaded to.
-#
-start:		cld				# String ops inc
-		xorw %ax,%ax			# Zero
-		movw %ax,%es			# Address
-		movw %ax,%ds			#  data
-		movw %ax,%ss			# Set up
-		movw $LOAD,%sp			#  stack
-
-#
-# Copy this code to the address it was linked for
-#
-		movw %sp,%si			# Source
-		movw $start,%di			# Destination
-		movw $0x100,%cx			# Word count
-		rep				# Relocate
-		movsw				#  code
-#
-# Set address for variable space beyond code, and clear it.
-# Notice that this is also used to point to the values embedded in the block,
-# by using negative offsets.
-#
-		movw %di,%bp			# Address variables
-		movb $0x8,%cl			# Words to clear
-		rep				# Zero
-		stosw				#  them
-#
-# Relocate to the new copy of the code.
-#
-		incb -0xe(%di)			# Sector number
-		jmp main-LOAD+ORIGIN		# To relocated code
-
-#
-# Initialize the serial port.
-# Must save DX (contains drive number)
-#
-main:		pushw %dx			# Save
-		xorw %dx,%dx			# Port: COM1
-		movb COMSPEED,%al		# defined by Makefile
-		movb $0x00,%ah			# BIOS: Set COM Port
-		int $0x14			#  Parameters
-		popw %dx			# Restore
-#
-# Check what flags were loaded with us, specifically, Use a predefined Drive.
-# If what the bios gives us is bad, use the '0' in the block instead, as well.
-#
-		testb $0x20,_FLAGS(%bp)		# Set number drive?
-		jnz main.1			# Yes
-		testb %dl,%dl			# Drive number valid?
-		js main.2			# Possibly (0x80 set)
-main.1:		movb _SETDRV(%bp),%dl		# Drive number to use
-#
-# Whatever we decided to use, now store it into the fake
-# partition entry that lives in the data space above us.
-#
-main.2:		movb %dl,_FAKE(%bp)		# Save drive number
-		callw putn			# To new line
-		pushw %dx			# Save drive number
-#
-# Start out with a pointer to the 4th byte of the first table entry
-# so that after 4 iterations it's beyond the end of the sector.
-# and beyond a 256 byte boundary and has overflowed 8 bits (see next comment).
-# (remember that the table starts 2 bytes earlier than you would expect
-# as the bootable flag is after it in the block)
-#
-		movw $(partbl+0x4),%bx		# Partition table (+4)
-		xorw %dx,%dx			# Item number
-#
-# Loop around on the partition table, printing values until we
-# pass a 256 byte boundary. The end of loop test is at main.5.
-#
-main.3:		movb %ch,-0x4(%bx)		# Zero active flag (ch == 0)
-		btw %dx,_FLAGS(%bp)		# Entry enabled?
-		jnc main.5			# No
-#
-# If any of the entries in the table are
-# the same as the 'type' in the slice table entry,
-# then this is an empty or non bootable partition. Skip it.
-#
-		movb (%bx),%al			# Load type
-		movw $tables,%di		# Lookup tables
-		movb $TBL0SZ,%cl		# Number of entries
-		repne				# Exclude
-		scasb				#  partition?
-		je main.5			# Yes
-#
-# Now scan the table of known types
-#
-		movb $TBL1SZ,%cl		# Number of entries
-		repne				# Known
-		scasb				#  type?
-		jne main.4			# No
-#
-# If it matches get the matching element in the
-# next array. if it doesn't, we are already
-# pointing at its first element which points to a "?".
-#
-		addw $TBL1SZ,%di		# Adjust
-main.4:		movb (%di),%cl			# Partition
-		addw %cx,%di			#  description
-		callw putx			# Display it
-main.5:		incw %dx			# Next item
-		addb $0x10,%bl			# Next entry
-		jnc main.3			# Till done
-#
-# Passed a 256 byte boundary..
-# table is finished.
-# Add one to the drive number and check it is valid,
-#
-		popw %ax			# Drive number
-		subb $0x80-0x1,%al		# Does next
-		cmpb NHRDRV,%al			#  drive exist? (from BIOS?)
-		jb main.6			# Yes
-# If not then if there is only one drive,
-# Don't display drive as an option.
-#
-		decw %ax			# Already drive 0?
-		jz main.7			# Yes
-# If it was illegal or we cycled through them,
-# then go back to drive 0.
-#
-		xorb %al,%al			# Drive 0
-#
-# Whatever drive we selected, make it an ascii digit and save it back
-# to the "next drive" location in the loaded block in case we
-# want to save it for next time.
-# This also is part of the printed drive string so add 0x80 to indicate
-# end of string.
-#
-main.6:		addb $'0'|0x80,%al		# Save next
-		movb %al,_NXTDRV(%bp)		#  drive number
-		movw $drive,%di			# Display
-		callw putx			#  item
-#
-# Now that we've printed the drive (if we needed to), display a prompt.
-# Get ready for the input byte noting the time.
-#
-main.7:		movw $prompt,%si		# Display
-		callw putstr			#  prompt
-		movb _OPT(%bp),%dl		# Display
-		decw %si			#  default
-		callw putkey			#  key
-main.7_1:
-		xorb %ah,%ah			# BIOS: Get
-		int $0x1a			#  system time
-		movw %dx,%si			# Ticks when
-		addw _TICKS(%bp),%si		#  timeout
-
-#
-# Busy loop, checking for a character on the serial port, but
-# keeping one eye on the time.
-#
-
-main.8:		xorw %dx,%dx			# Use COM1
-		movb $0x03,%ah			# BIOS: Read COM
-		int $0x14			#  Status
-		testb $0x01,%ah			# Check line status
-		jnz main.11 			# (bit 1 indicates input)
-
-		xorb %ah,%ah			# BIOS: Get
-		int $0x1a			#  system time
-		cmpw %si,%dx			# Timeout?
-		jb main.8			# No
-
-#
-# If timed out or defaulting, come here.
-#
-main.9:		movb _OPT(%bp),%al		# Load default
-		jmp main.12			# Join common code
-#
-# User's last try was bad, beep in displeasure.
-# Since nothing was printed, just continue on as if the user
-# hadn't done anything. This gives the effect of the user getting a beep
-# for all bad keystrokes but no action until either the timeout
-# occurs or the user hits a good key.
-#
-main.10:	movb $ASCII_BEL,%al		# Signal
-		callw putchr			#  error
-		jmp main.7_1			# Go back
-#
-# Check the character we just got on the serial port.
-#
-main.11:	movb $0x02,%ah			# BIOS: Receive
-		int $0x14			#  COM Byte
-#
-# If it's CR act as if timed out.
-#
-		cmpb $ASCII_CR,%al		# Enter pressed?
-		je main.9			# Yes
-#
-# Otherwise check if legal
-# If not ask again.
-#
-		subb $ASCII_1,%al		# Less '1' ascii character
-		cmpb $0x4,%al			# #1..#5?
-		ja main.10			# No
-#
-# We have a selection.
-# but if it's a bad selection go back to complain.
-# The bits in MNUOPT were set when the options were printed.
-# Anything not printed is not an option.
-#
-main.12:	cbtw				# Option
-		btw %ax,_MNUOPT(%bp)	 	#  enabled?
-		jnc main.10			# No
-#
-# Save the info in the original tables
-# for rewriting to the disk.
-#
-		movb %al,_OPT(%bp)		# Save option
-		movw $FAKE,%si			# Partition for write
-		movb (%si),%dl			# Drive number
-		movw %si,%bx			# Partition for read
-		cmpb $0x4,%al			# F5/#5 pressed?
-		pushf				# Save
-		je main.13			# Yes
-		shlb $0x4,%al			# Point to
-		addw $partbl,%ax		#  selected
-		xchgw %bx,%ax	 		#  partition
-		movb $0x80,(%bx)		# Flag active
-#
-# If not asked to do a write-back (flags 0x40) don't do one.
-#
-main.13:	pushw %bx			# Save
-		testb $0x40,_FLAGS(%bp)		# No updates?
-		jnz main.14			# Yes
-		movw $start,%bx			# Data to write
-		movb $0x3,%ah			# Write sector
-		callw intx13			#  to disk
-main.14:	popw %si			# Restore
-		popf				# Restore
-#
-# If going to next drive, replace drive with selected one.
-# Remember to un-ascii it. Hey 0x80 is already set, cool!
-#
-		jne main.15			# If not F5/#5
-		movb _NXTDRV(%bp),%dl		# Next drive
-		subb $'0',%dl			#  number
-#
-# load  selected bootsector to the LOAD location in RAM.
-# If it fails to read or isn't marked bootable, treat it
-# as a bad selection.
-# XXX what does %si carry?
-#
-main.15:	movw $LOAD,%bx			# Address for read
-		movb $0x2,%ah			# Read sector
-		callw intx13			#  from disk
-		jc main.10			# If error
-		cmpw $MAGIC,0x1fe(%bx)		# Bootable?
-		jne main.10			# No
-		pushw %si			# Save
-		movw $crlf,%si			# Leave some
-		callw puts			#  space
-		popw %si			# Restore
-		jmp *%bx			# Invoke bootstrap
-#
-# Display routines
-#
-
-putkey:		movb $ASCII_1,%al		# Prepare
-		addb %dl,%al			#  digit
-		jmp putstr.1			# Display the rest
-
-#
-# Display the option and note that it is a valid option.
-# That last point is a bit tricky..
-#
-putx:		btsw %dx,_MNUOPT(%bp)		# Enable menu option
-		movw $item,%si			# Display
-		callw putkey			#  key
-		movw %di,%si			# Display the rest
-
-puts:		callw putstr			# Display string
-
-putn:		movw $crlf,%si			# To next line
-
-putstr:		lodsb				# Get byte
-		testb $0x80,%al 		# End of string?
-		jnz putstr.2			# Yes
-putstr.1:	callw putchr			# Display char
-		jmp putstr			# Continue
-putstr.2:	andb $~0x80,%al 		# Clear MSB
-
-putchr:		pushw %dx			# Save
-		xorw %dx,%dx 			# Use COM1
-		xorw %cx,%cx 			# No timeout
-		movb $0x01,%ah			# BIOS: Send
-		int $0x14			#  Character
-		popw %dx			# Restore
-		retw				# To caller
-
-# One-sector disk I/O routine
-
-intx13:		movb 0x1(%si),%dh		# Load head
-		movw 0x2(%si),%cx		# Load cylinder:sector
-		movb $0x1,%al			# Sector count
-		pushw %si			# Save
-		movw %sp,%di			# Save
-		testb $0x80,_FLAGS(%bp)		# Use packet interface?
-		jz intx13.1			# No
-		pushl $0x0			# Set the
-		pushl 0x8(%si)			# LBA address
-		pushw %es			# Set the transfer
-		pushw %bx			#  buffer address
-		push  $0x1			# Block count
-		push  $0x10			# Packet size
-		movw %sp,%si			# Packet pointer
-		decw %ax			# Verify off
-		orb $0x40,%ah			# Use disk packet
-intx13.1:	int $0x13			# BIOS: Disk I/O
-		movw %di,%sp			# Restore
-		popw %si			# Restore
-		retw				# To caller
-
-# Menu strings
-
-item:		.ascii " ";	     .byte ' '|0x80
-prompt:		.ascii "\nDef:";     .byte ' '|0x80
-crlf:		.ascii "\r";	     .byte '\n'|0x80
-
-# Partition type tables
-
-tables:
-#
-# These entries identify invalid or NON BOOT types and partitions.
-#
-		.byte 0x0, 0x5, 0xf
-#
-# These values indicate bootable types we know the names of
-#
-		.byte 0x1, 0x4, 0x6, 0xb, 0xc, 0xe, 0x83
-		.byte 0x9f, 0xa5, 0xa6, 0xa9
-#
-# These are offsets that match the known names above and point to the strings
-# that will be printed.
-#
-		.byte os_misc-. 		# Unknown
-		.byte os_dos-.			# DOS
-		.byte os_dos-.			# DOS
-		.byte os_dos-.			# DOS
-		.byte os_dos-.			# Windows
-		.byte os_dos-.			# Windows
-		.byte os_dos-.			# Windows
-		.byte os_linux-.		# Linux
-		.byte os_bsd-.			# BSD/OS
-		.byte os_freebsd-.		# FreeBSD
-		.byte os_bsd-.			# OpenBSD
-		.byte os_bsd-.			# NetBSD
-#
-# And here are the strings themselves. 0x80 or'd into a byte indicates
-# the end of the string. (not so great for Russians but...)
-#
-os_misc:	.ascii "?";    .byte '?'|0x80
-os_dos:		.ascii "DO";   .byte 'S'|0x80
-os_linux:	.ascii "Linu"; .byte 'x'|0x80
-os_freebsd:	.ascii "Free"
-os_bsd:		.ascii "BS";   .byte 'D'|0x80
-
-		.org PRT_OFF-0xe,0x90
-
-		.word B0MAGIC			# Magic number
-
-#
-# These values are sometimes changed before writing back to the drive
-# Be especially careful that nxtdrv: must come after drive:, as it
-# is part of the same string.
-#
-drive:		.ascii "Drive "
-nxtdrv:		.byte 0x0			# Next drive number
-opt:		.byte 0x0			# Option
-setdrv:		.byte 0x80			# Drive to force
-flags:		.byte FLAGS			# Flags
-ticks:		.word TICKS			# Delay
-
-#
-# here is the 64 byte partition table that fdisk would fiddle with.
-#
-partbl:		.fill 0x40,0x1,0x0		# Partition table
-		.word MAGIC			# Magic number
diff --git a/sys/boot/i386/boot0/boot0.s b/sys/boot/i386/boot0/boot0.s
deleted file mode 100644
index 25fa8f0..0000000
--- a/sys/boot/i386/boot0/boot0.s
+++ /dev/null
@@ -1,419 +0,0 @@
-#
-# Copyright (c) 1998 Robert Nordier
-# All rights reserved.
-#
-# Redistribution and use in source and binary forms are freely
-# permitted provided that the above copyright notice and this
-# paragraph and the following disclaimer are duplicated in all
-# such forms.
-#
-# This software is provided "AS IS" and without any express or
-# implied warranties, including, without limitation, the implied
-# warranties of merchantability and fitness for a particular
-# purpose.
-#
-
-# $FreeBSD$
-
-# A 512-byte boot manager.
-
-		.set NHRDRV,0x475		# Number of hard drives
-		.set ORIGIN,0x600		# Execution address
-		.set FAKE,0x800 		# Partition entry
-		.set LOAD,0x7c00		# Load address
-
-		.set PRT_OFF,0x1be		# Partition table
-
-		.set TBL0SZ,0x3 		# Table 0 size
-		.set TBL1SZ,0xb 		# Table 1 size
-
-		.set MAGIC,0xaa55		# Magic: bootable
-		.set B0MAGIC,0xbb66		# Identification
-
-		.set KEY_ENTER,0x1c		# Enter key scan code
-		.set KEY_F1,0x3b		# F1 key scan code
-		.set KEY_1,0x02			# #1 key scan code
-
-#
-# Addresses in the sector of embedded data values.
-# Accessed with negative offsets from the end of the relocated sector (%ebp).
-#
-		.set _NXTDRV,-0x48		# Next drive
-		.set _OPT,-0x47 		# Default option
-		.set _SETDRV,-0x46		# Drive to force
-		.set _FLAGS,-0x45		# Flags
-		.set _TICKS,-0x44		# Timeout ticks
-		.set _FAKE,0x0			# Fake partition entry
-		.set _MNUOPT,0xc		# Menu options
-
-		.globl start			# Entry point
-		.code16				# This runs in real mode
-
-#
-# Initialise segments and registers to known values.
-# segments start at 0.
-# The stack is immediately below the address we were loaded to.
-#
-start:		cld				# String ops inc
-		xorw %ax,%ax			# Zero
-		movw %ax,%es			# Address
-		movw %ax,%ds			#  data
-		movw %ax,%ss			# Set up
-		movw $LOAD,%sp			#  stack
-
-#
-# Copy this code to the address it was linked for
-#
-		movw %sp,%si			# Source
-		movw $start,%di			# Destination
-		movw $0x100,%cx			# Word count
-		rep				# Relocate
-		movsw				#  code
-#
-# Set address for variable space beyond code, and clear it.
-# Notice that this is also used to point to the values embedded in the block,
-# by using negative offsets.
-#
-		movw %di,%bp			# Address variables
-		movb $0x8,%cl			# Words to clear
-		rep				# Zero
-		stosw				#  them
-#
-# Relocate to the new copy of the code.
-#
-		incb -0xe(%di)			# Sector number
-		jmp main-LOAD+ORIGIN		# To relocated code
-#
-# Check what flags were loaded with us, specifically, Use a predefined Drive.
-# If what the bios gives us is bad, use the '0' in the block instead, as well.
-#
-main:		testb $0x20,_FLAGS(%bp)		# Set number drive?
-		jnz main.1			# Yes
-		testb %dl,%dl			# Drive number valid?
-		js main.2			# Possibly (0x80 set)
-main.1:		movb _SETDRV(%bp),%dl		# Drive number to use
-#
-# Whatever we decided to use, now store it into the fake
-# partition entry that lives in the data space above us.
-#
-main.2:		movb %dl,_FAKE(%bp)		# Save drive number
-		callw putn			# To new line
-		pushw %dx			# Save drive number
-#
-# Start out with a pointer to the 4th byte of the first table entry
-# so that after 4 iterations it's beyond the end of the sector.
-# and beyond a 256 byte boundary and has overflowed 8 bits (see next comment).
-# (remember that the table starts 2 bytes earlier than you would expect
-# as the bootable flag is after it in the block)
-#
-		movw $(partbl+0x4),%bx		# Partition table (+4)
-		xorw %dx,%dx			# Item number
-#
-# Loop around on the partition table, printing values until we
-# pass a 256 byte boundary. The end of loop test is at main.5.
-#
-main.3:		movb %ch,-0x4(%bx)		# Zero active flag (ch == 0)
-		btw %dx,_FLAGS(%bp)		# Entry enabled?
-		jnc main.5			# No
-#
-# If any of the entries in the table are
-# the same as the 'type' in the slice table entry,
-# then this is an empty or non bootable partition. Skip it.
-#
-		movb (%bx),%al			# Load type
-		movw $tables,%di		# Lookup tables
-		movb $TBL0SZ,%cl		# Number of entries
-		repne				# Exclude
-		scasb				#  partition?
-		je main.5			# Yes
-#
-# Now scan the table of known types
-#
-		movb $TBL1SZ,%cl		# Number of entries
-		repne				# Known
-		scasb				#  type?
-		jne main.4			# No
-#
-# If it matches get the matching element in the
-# next array. if it doesn't, we are already
-# pointing at its first element which points to a "?".
-#
-		addw $TBL1SZ,%di		# Adjust
-main.4:		movb (%di),%cl			# Partition
-		addw %cx,%di			#  description
-		callw putx			# Display it
-main.5:		incw %dx			# Next item
-		addb $0x10,%bl			# Next entry
-		jnc main.3			# Till done
-#
-# Passed a 256 byte boundary..
-# table is finished.
-# Add one to the drive number and check it is valid,
-#
-		popw %ax			# Drive number
-		subb $0x80-0x1,%al		# Does next
-		cmpb NHRDRV,%al			#  drive exist? (from BIOS?)
-		jb main.6			# Yes
-# If not then if there is only one drive,
-# Don't display drive as an option.
-#
-		decw %ax			# Already drive 0?
-		jz main.7			# Yes
-# If it was illegal or we cycled through them,
-# then go back to drive 0.
-#
-		xorb %al,%al			# Drive 0
-#
-# Whatever drive we selected, make it an ascii digit and save it back
-# to the "next drive" location in the loaded block in case we
-# want to save it for next time.
-# This also is part of the printed drive string so add 0x80 to indicate
-# end of string.
-#
-main.6:		addb $'0'|0x80,%al		# Save next
-		movb %al,_NXTDRV(%bp)		#  drive number
-		movw $drive,%di			# Display
-		callw putx			#  item
-#
-# Now that we've printed the drive (if we needed to), display a prompt.
-# Get ready for the input by noting the time.
-#
-main.7:		movw $prompt,%si		# Display
-		callw putstr			#  prompt
-		movb _OPT(%bp),%dl		# Display
-		decw %si			#  default
-		callw putkey			#  key
-		xorb %ah,%ah			# BIOS: Get
-		int $0x1a			#  system time
-		movw %dx,%di			# Ticks when
-		addw _TICKS(%bp),%di	 	#  timeout
-#
-# Busy loop, looking for keystrokes but
-# keeping one eye on the time.
-#
-main.8:		movb $0x1,%ah			# BIOS: Check
-		int $0x16			#  for keypress
-		jnz main.11			# Have one
-		xorb %ah,%ah			# BIOS: Get
-		int $0x1a			#  system time
-		cmpw %di,%dx			# Timeout?
-		jb main.8			# No
-#
-# If timed out or defaulting, come here.
-#
-main.9:		movb _OPT(%bp),%al		# Load default
-		jmp main.12			# Join common code
-#
-# User's last try was bad, beep in displeasure.
-# Since nothing was printed, just continue on as if the user
-# hadn't done anything. This gives the effect of the user getting a beep
-# for all bad keystrokes but no action until either the timeout
-# occurs or the user hits a good key.
-#
-main.10:	movb $0x7,%al			# Signal
-		callw putchr			#  error
-#
-# Get the keystroke.
-#
-main.11:	xorb %ah,%ah			# BIOS: Get
-		int $0x16			#  keypress
-		movb %ah,%al			# Scan code
-#
-# If it's CR act as if timed out.
-#
-		cmpb $KEY_ENTER,%al		# Enter pressed?
-		je main.9			# Yes
-#
-# Otherwise check if legal
-# If not ask again.
-#
-		subb $KEY_F1,%al		# Less F1 scan code
-		cmpb $0x4,%al			# F1..F5?
-		jna main.12			# Yes
-		subb $(KEY_1 - KEY_F1),%al	# Less #1 scan code
-		cmpb $0x4,%al			# #1..#5?
-		ja main.10			# No
-#
-# We have a selection.
-# but if it's a bad selection go back to complain.
-# The bits in MNUOPT were set when the options were printed.
-# Anything not printed is not an option.
-#
-main.12:	cbtw				# Option
-		btw %ax,_MNUOPT(%bp)	 	#  enabled?
-		jnc main.10			# No
-#
-# Save the info in the original tables
-# for rewriting to the disk.
-#
-		movb %al,_OPT(%bp)		# Save option
-		movw $FAKE,%si			# Partition for write
-		movb (%si),%dl			# Drive number
-		movw %si,%bx			# Partition for read
-		cmpb $0x4,%al			# F5/#5 pressed?
-		pushf				# Save
-		je main.13			# Yes
-		shlb $0x4,%al			# Point to
-		addw $partbl,%ax		#  selected
-		xchgw %bx,%ax	 		#  partition
-		movb $0x80,(%bx)		# Flag active
-#
-# If not asked to do a write-back (flags 0x40) don't do one.
-#
-main.13:	pushw %bx			# Save
-		testb $0x40,_FLAGS(%bp)		# No updates?
-		jnz main.14			# Yes
-		movw $start,%bx			# Data to write
-		movb $0x3,%ah			# Write sector
-		callw intx13			#  to disk
-main.14:	popw %si			# Restore
-		popf				# Restore
-#
-# If going to next drive, replace drive with selected one.
-# Remember to un-ascii it. Hey 0x80 is already set, cool!
-#
-		jne main.15			# If not F5/#5
-		movb _NXTDRV(%bp),%dl		# Next drive
-		subb $'0',%dl			#  number
-#
-# load  selected bootsector to the LOAD location in RAM.
-# If it fails to read or isn't marked bootable, treat it
-# as a bad selection.
-# XXX what does %si carry?
-#
-main.15:	movw $LOAD,%bx			# Address for read
-		movb $0x2,%ah			# Read sector
-		callw intx13			#  from disk
-		jc main.10			# If error
-		cmpw $MAGIC,0x1fe(%bx)		# Bootable?
-		jne main.10			# No
-		pushw %si			# Save
-		movw $crlf,%si			# Leave some
-		callw puts			#  space
-		popw %si			# Restore
-		jmp *%bx			# Invoke bootstrap
-#
-# Display routines
-#
-
-putkey:		movb $'F',%al			# Display
-		callw putchr			#  'F'
-		movb $'1',%al			# Prepare
-		addb %dl,%al			#  digit
-		jmp putstr.1			# Display the rest
-
-#
-# Display the option and note that it is a valid option.
-# That last point is a bit tricky..
-#
-putx:		btsw %dx,_MNUOPT(%bp)		# Enable menu option
-		movw $item,%si			# Display
-		callw putkey			#  key
-		movw %di,%si			# Display the rest
-
-puts:		callw putstr			# Display string
-
-putn:		movw $crlf,%si			# To next line
-
-putstr:		lodsb				# Get byte
-		testb $0x80,%al 		# End of string?
-		jnz putstr.2			# Yes
-putstr.1:	callw putchr			# Display char
-		jmp putstr			# Continue
-putstr.2:	andb $~0x80,%al 		# Clear MSB
-
-putchr:		pushw %bx			# Save
-		movw $0x7,%bx	 		# Page:attribute
-		movb $0xe,%ah			# BIOS: Display
-		int $0x10			#  character
-		popw %bx			# Restore
-		retw				# To caller
-
-# One-sector disk I/O routine
-
-intx13:		movb 0x1(%si),%dh		# Load head
-		movw 0x2(%si),%cx		# Load cylinder:sector
-		movb $0x1,%al			# Sector count
-		pushw %si			# Save
-		movw %sp,%di			# Save
-		testb $0x80,_FLAGS(%bp)		# Use packet interface?
-		jz intx13.1			# No
-		pushl $0x0			# Set the
-		pushl 0x8(%si)			# LBA address
-		pushw %es			# Set the transfer
-		pushw %bx			#  buffer address
-		push  $0x1			# Block count
-		push  $0x10			# Packet size
-		movw %sp,%si			# Packet pointer
-		decw %ax			# Verify off
-		orb $0x40,%ah			# Use disk packet
-intx13.1:	int $0x13			# BIOS: Disk I/O
-		movw %di,%sp			# Restore
-		popw %si			# Restore
-		retw				# To caller
-
-# Menu strings
-
-item:		.ascii "  ";	     .byte ' '|0x80
-prompt:		.ascii "\nDefault:"; .byte ' '|0x80
-crlf:		.ascii "\r";	     .byte '\n'|0x80
-
-# Partition type tables
-
-tables:
-#
-# These entries identify invalid or NON BOOT types and partitions.
-#
-		.byte 0x0, 0x5, 0xf
-#
-# These values indicate bootable types we know the names of
-#
-		.byte 0x1, 0x4, 0x6, 0xb, 0xc, 0xe, 0x83
-		.byte 0x9f, 0xa5, 0xa6, 0xa9
-#
-# These are offsets that match the known names above and point to the strings
-# that will be printed.
-#
-		.byte os_misc-. 		# Unknown
-		.byte os_dos-.			# DOS
-		.byte os_dos-.			# DOS
-		.byte os_dos-.			# DOS
-		.byte os_dos-.			# Windows
-		.byte os_dos-.			# Windows
-		.byte os_dos-.			# Windows
-		.byte os_linux-.		# Linux
-		.byte os_bsd-.			# BSD/OS
-		.byte os_freebsd-.		# FreeBSD
-		.byte os_bsd-.			# OpenBSD
-		.byte os_bsd-.			# NetBSD
-#
-# And here are the strings themselves. 0x80 or'd into a byte indicates
-# the end of the string. (not so great for Russians but...)
-#
-os_misc:	.ascii "?";    .byte '?'|0x80
-os_dos:		.ascii "DO";   .byte 'S'|0x80
-os_linux:	.ascii "Linu"; .byte 'x'|0x80
-os_freebsd:	.ascii "Free"
-os_bsd:		.ascii "BS";   .byte 'D'|0x80
-
-		.org PRT_OFF-0xe,0x90
-
-		.word B0MAGIC			# Magic number
-
-#
-# These values are sometimes changed before writing back to the drive
-# Be especially careful that nxtdrv: must come after drive:, as it
-# is part of the same string.
-#
-drive:		.ascii "Drive "
-nxtdrv:		.byte 0x0			# Next drive number
-opt:		.byte 0x0			# Option
-setdrv:		.byte 0x80			# Drive to force
-flags:		.byte FLAGS			# Flags
-ticks:		.word TICKS			# Delay
-
-#
-# here is the 64 byte partition table that fdisk would fiddle with.
-#
-partbl:		.fill 0x40,0x1,0x0		# Partition table
-		.word MAGIC			# Magic number
diff --git a/sys/boot/i386/boot0/boot0_512.s b/sys/boot/i386/boot0/boot0_512.s
new file mode 100644
index 0000000..6d33c44
--- /dev/null
+++ b/sys/boot/i386/boot0/boot0_512.s
@@ -0,0 +1,494 @@
+//
+// Copyright (c) 2002 Bruce M. Simpson
+// Copyright (c) 1998 Robert Nordier
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms are freely
+// permitted provided that the above copyright notice and this
+// paragraph and the following disclaimer are duplicated in all
+// such forms.
+//
+// This software is provided "AS IS" and without any express or
+// implied warranties, including, without limitation, the implied
+// warranties of merchantability and fitness for a particular
+// purpose.
+//
+
+// $FreeBSD$
+
+// A 512-byte boot manager.
+#ifdef SIO
+// ... using serial port COM1
+#endif /* SIO */
+
+		.set NHRDRV,0x475		// Number of hard drives
+		.set ORIGIN,0x600		// Execution address
+		.set FAKE,0x800 		// Partition entry
+		.set LOAD,0x7c00		// Load address
+
+		.set PRT_OFF,0x1be		// Partition table
+
+		.set TBL0SZ,0x3 		// Table 0 size
+		.set TBL1SZ,0xb 		// Table 1 size
+
+		.set MAGIC,0xaa55		// Magic: bootable
+		.set B0MAGIC,0xbb66		// Identification
+
+		.set KEY_ENTER,0x1c		// Enter key scan code
+		.set KEY_F1,0x3b		// F1 key scan code
+		.set KEY_1,0x02			// #1 key scan code
+
+		.set ASCII_BEL,0x07		// ASCII code for <BEL>
+		.set ASCII_CR,0x0D		// ASCII code for <CR>
+
+//
+// Addresses in the sector of embedded data values.
+// Accessed with negative offsets from the end of the relocated sector (%ebp).
+//
+		.set _NXTDRV,-0x48		// Next drive
+		.set _OPT,-0x47 		// Default option
+		.set _SETDRV,-0x46		// Drive to force
+		.set _FLAGS,-0x45		// Flags
+		.set _TICKS,-0x44		// Timeout ticks
+		.set _FAKE,0x0			// Fake partition entry
+		.set _MNUOPT,0xc		// Menu options
+
+		.globl start			// Entry point
+		.code16				// This runs in real mode
+
+//
+// Initialise segments and registers to known values.
+// segments start at 0.
+// The stack is immediately below the address we were loaded to.
+//
+start:		cld				// String ops inc
+		xorw %ax,%ax			// Zero
+		movw %ax,%es			// Address
+		movw %ax,%ds			//  data
+		movw %ax,%ss			// Set up
+		movw $LOAD,%sp			//  stack
+
+//
+// Copy this code to the address it was linked for
+//
+		movw %sp,%si			// Source
+		movw $start,%di			// Destination
+		movw $0x100,%cx			// Word count
+		rep				// Relocate
+		movsw				//  code
+//
+// Set address for variable space beyond code, and clear it.
+// Notice that this is also used to point to the values embedded in the block,
+// by using negative offsets.
+//
+		movw %di,%bp			// Address variables
+		movb $0x8,%cl			// Words to clear
+		rep				// Zero
+		stosw				//  them
+//
+// Relocate to the new copy of the code.
+//
+		incb -0xe(%di)			// Sector number
+		jmp main-LOAD+ORIGIN		// To relocated code
+main:
+
+#ifdef SIO
+
+//
+// Initialize the serial port.
+// Must save DX (contains drive number)
+//
+		pushw %dx			// Save
+		xorw %dx,%dx			// Port: COM1
+		movb COMSPEED,%al		// defined by Makefile
+		movb $0x00,%ah			// BIOS: Set COM Port
+		int $0x14			//  Parameters
+		popw %dx			// Restore
+#endif /* SIO */
+//
+// Check what flags were loaded with us, specifically, Use a predefined Drive.
+// If what the bios gives us is bad, use the '0' in the block instead, as well.
+//
+		testb $0x20,_FLAGS(%bp)		// Set number drive?
+		jnz main.1			// Yes
+		testb %dl,%dl			// Drive number valid?
+		js main.2			// Possibly (0x80 set)
+main.1:		movb _SETDRV(%bp),%dl		// Drive number to use
+//
+// Whatever we decided to use, now store it into the fake
+// partition entry that lives in the data space above us.
+//
+main.2:		movb %dl,_FAKE(%bp)		// Save drive number
+		callw putn			// To new line
+		pushw %dx			// Save drive number
+//
+// Start out with a pointer to the 4th byte of the first table entry
+// so that after 4 iterations it's beyond the end of the sector.
+// and beyond a 256 byte boundary and has overflowed 8 bits (see next comment).
+// (remember that the table starts 2 bytes earlier than you would expect
+// as the bootable flag is after it in the block)
+//
+		movw $(partbl+0x4),%bx		// Partition table (+4)
+		xorw %dx,%dx			// Item number
+//
+// Loop around on the partition table, printing values until we
+// pass a 256 byte boundary. The end of loop test is at main.5.
+//
+main.3:		movb %ch,-0x4(%bx)		// Zero active flag (ch == 0)
+		btw %dx,_FLAGS(%bp)		// Entry enabled?
+		jnc main.5			// No
+//
+// If any of the entries in the table are
+// the same as the 'type' in the slice table entry,
+// then this is an empty or non bootable partition. Skip it.
+//
+		movb (%bx),%al			// Load type
+		movw $tables,%di		// Lookup tables
+		movb $TBL0SZ,%cl		// Number of entries
+		repne				// Exclude
+		scasb				//  partition?
+		je main.5			// Yes
+//
+// Now scan the table of known types
+//
+		movb $TBL1SZ,%cl		// Number of entries
+		repne				// Known
+		scasb				//  type?
+		jne main.4			// No
+//
+// If it matches get the matching element in the
+// next array. if it doesn't, we are already
+// pointing at its first element which points to a "?".
+//
+		addw $TBL1SZ,%di		// Adjust
+main.4:		movb (%di),%cl			// Partition
+		addw %cx,%di			//  description
+		callw putx			// Display it
+main.5:		incw %dx			// Next item
+		addb $0x10,%bl			// Next entry
+		jnc main.3			// Till done
+//
+// Passed a 256 byte boundary..
+// table is finished.
+// Add one to the drive number and check it is valid,
+//
+		popw %ax			// Drive number
+		subb $0x80-0x1,%al		// Does next
+		cmpb NHRDRV,%al			//  drive exist? (from BIOS?)
+		jb main.6			// Yes
+// If not then if there is only one drive,
+// Don't display drive as an option.
+//
+		decw %ax			// Already drive 0?
+		jz main.7			// Yes
+// If it was illegal or we cycled through them,
+// then go back to drive 0.
+//
+		xorb %al,%al			// Drive 0
+//
+// Whatever drive we selected, make it an ascii digit and save it back
+// to the "next drive" location in the loaded block in case we
+// want to save it for next time.
+// This also is part of the printed drive string so add 0x80 to indicate
+// end of string.
+//
+main.6:		addb $'0'|0x80,%al		// Save next
+		movb %al,_NXTDRV(%bp)		//  drive number
+		movw $drive,%di			// Display
+		callw putx			//  item
+//
+// Now that we've printed the drive (if we needed to), display a prompt.
+// Get ready for the input by noting the time.
+//
+main.7:		movw $prompt,%si		// Display
+		callw putstr			//  prompt
+		movb _OPT(%bp),%dl		// Display
+		decw %si			//  default
+		callw putkey			//  key
+main.7_1:
+		xorb %ah,%ah			// BIOS: Get
+		int $0x1a			//  system time
+#ifndef SIO
+		movw %dx,%di			// Ticks when
+		addw _TICKS(%bp),%di	 	//  timeout
+#else /* SIO */
+		movw %dx,%si			// Ticks when
+		addw _TICKS(%bp),%si		//  timeout
+#endif /* SIO */
+//
+// Busy loop, looking for keystrokes but
+// keeping one eye on the time.
+//
+main.8:
+#ifndef SIO
+		movb $0x1,%ah			// BIOS: Check
+		int $0x16			//  for keypress
+		jnz main.11			// Have one
+#else /* SIO */
+		xorw %dx,%dx			// Use COM1
+		movb $0x03,%ah			// BIOS: Read COM
+		int $0x14			//  Status
+		testb $0x01,%ah			// Check line status
+		jnz main.11 			// (bit 1 indicates input)
+#endif /* SIO */
+		xorb %ah,%ah			// BIOS: Get
+		int $0x1a			//  system time
+#ifndef SIO
+		cmpw %di,%dx			// Timeout?
+#else /* SIO */
+		cmpw %si,%dx			// Timeout?
+#endif /* SIO */
+		jb main.8			// No
+//
+// If timed out or defaulting, come here.
+//
+main.9:		movb _OPT(%bp),%al		// Load default
+		jmp main.12			// Join common code
+//
+// User's last try was bad, beep in displeasure.
+// Since nothing was printed, just continue on as if the user
+// hadn't done anything. This gives the effect of the user getting a beep
+// for all bad keystrokes but no action until either the timeout
+// occurs or the user hits a good key.
+//
+main.10:	movb $ASCII_BEL,%al		// Signal
+		callw putchr			//  error
+#ifdef SIO
+		jmp main.7_1			// Go back
+#endif /* SIO */
+//
+// Get the keystroke.
+//
+main.11:
+#ifndef SIO
+		xorb %ah,%ah			// BIOS: Get
+		int $0x16			//  keypress
+		movb %ah,%al			// Scan code
+#else /* SIO */
+		movb $0x02,%ah			// BIOS: Receive
+		int $0x14			//  COM Byte
+#endif /* SIO */
+//
+// If it's CR act as if timed out.
+//
+#ifndef SIO
+		cmpb $KEY_ENTER,%al		// Enter pressed?
+#else /* SIO */
+		cmpb $ASCII_CR,%al		// Enter pressed?
+#endif /* SIO */
+		je main.9			// Yes
+//
+// Otherwise check if legal
+// If not ask again.
+//
+#ifndef SIO
+		subb $KEY_F1,%al		// Less F1 scan code
+		cmpb $0x4,%al			// F1..F5?
+		jna main.12			// Yes
+		subb $(KEY_1 - KEY_F1),%al	// Less #1 scan code
+#else /* SIO */
+		subb $'1',%al			// Less '1' ascii character
+#endif /* SIO */
+		cmpb $0x4,%al			// #1..#5?
+		ja main.10			// No
+//
+// We have a selection.
+// but if it's a bad selection go back to complain.
+// The bits in MNUOPT were set when the options were printed.
+// Anything not printed is not an option.
+//
+main.12:	cbtw				// Option
+		btw %ax,_MNUOPT(%bp)	 	//  enabled?
+		jnc main.10			// No
+//
+// Save the info in the original tables
+// for rewriting to the disk.
+//
+		movb %al,_OPT(%bp)		// Save option
+		movw $FAKE,%si			// Partition for write
+		movb (%si),%dl			// Drive number
+		movw %si,%bx			// Partition for read
+		cmpb $0x4,%al			// F5/#5 pressed?
+		pushf				// Save
+		je main.13			// Yes
+		shlb $0x4,%al			// Point to
+		addw $partbl,%ax		//  selected
+		xchgw %bx,%ax	 		//  partition
+		movb $0x80,(%bx)		// Flag active
+//
+// If not asked to do a write-back (flags 0x40) don't do one.
+//
+main.13:	pushw %bx			// Save
+		testb $0x40,_FLAGS(%bp)		// No updates?
+		jnz main.14			// Yes
+		movw $start,%bx			// Data to write
+		movb $0x3,%ah			// Write sector
+		callw intx13			//  to disk
+main.14:	popw %si			// Restore
+		popf				// Restore
+//
+// If going to next drive, replace drive with selected one.
+// Remember to un-ascii it. Hey 0x80 is already set, cool!
+//
+		jne main.15			// If not F5/#5
+		movb _NXTDRV(%bp),%dl		// Next drive
+		subb $'0',%dl			//  number
+//
+// load  selected bootsector to the LOAD location in RAM.
+// If it fails to read or isn't marked bootable, treat it
+// as a bad selection.
+// XXX what does %si carry?
+//
+main.15:	movw $LOAD,%bx			// Address for read
+		movb $0x2,%ah			// Read sector
+		callw intx13			//  from disk
+		jc main.10			// If error
+		cmpw $MAGIC,0x1fe(%bx)		// Bootable?
+		jne main.10			// No
+		pushw %si			// Save
+		movw $crlf,%si			// Leave some
+		callw puts			//  space
+		popw %si			// Restore
+		jmp *%bx			// Invoke bootstrap
+//
+// Display routines
+//
+
+putkey:
+#ifndef SIO
+		movb $'F',%al			// Display
+		callw putchr			//  'F'
+#endif /* SIO */
+		movb $'1',%al			// Prepare
+		addb %dl,%al			//  digit
+		jmp putstr.1			// Display the rest
+
+//
+// Display the option and note that it is a valid option.
+// That last point is a bit tricky..
+//
+putx:		btsw %dx,_MNUOPT(%bp)		// Enable menu option
+		movw $item,%si			// Display
+		callw putkey			//  key
+		movw %di,%si			// Display the rest
+
+puts:		callw putstr			// Display string
+
+putn:		movw $crlf,%si			// To next line
+
+putstr:		lodsb				// Get byte
+		testb $0x80,%al 		// End of string?
+		jnz putstr.2			// Yes
+putstr.1:	callw putchr			// Display char
+		jmp putstr			// Continue
+putstr.2:	andb $~0x80,%al 		// Clear MSB
+
+#ifndef SIO
+putchr:		pushw %bx			// Save
+		movw $0x7,%bx	 		// Page:attribute
+		movb $0xe,%ah			// BIOS: Display
+		int $0x10			//  character
+		popw %bx			// Restore
+#else /* SIO */
+putchr:		pushw %dx			// Save
+		xorw %dx,%dx 			// Use COM1
+		xorw %cx,%cx 			// No timeout
+		movb $0x01,%ah			// BIOS: Send
+		int $0x14			//  Character
+		popw %dx			// Restore
+#endif /* SIO */
+		retw				// To caller
+
+// One-sector disk I/O routine
+
+intx13:		movb 0x1(%si),%dh		// Load head
+		movw 0x2(%si),%cx		// Load cylinder:sector
+		movb $0x1,%al			// Sector count
+		pushw %si			// Save
+		movw %sp,%di			// Save
+		testb $0x80,_FLAGS(%bp)		// Use packet interface?
+		jz intx13.1			// No
+		pushl $0x0			// Set the
+		pushl 0x8(%si)			// LBA address
+		pushw %es			// Set the transfer
+		pushw %bx			//  buffer address
+		push  $0x1			// Block count
+		push  $0x10			// Packet size
+		movw %sp,%si			// Packet pointer
+		decw %ax			// Verify off
+		orb $0x40,%ah			// Use disk packet
+intx13.1:	int $0x13			// BIOS: Disk I/O
+		movw %di,%sp			// Restore
+		popw %si			// Restore
+		retw				// To caller
+
+// Menu strings
+
+#ifndef SIO
+item:		.ascii "  ";	     .byte ' '|0x80
+prompt:		.ascii "\nDefault:"; .byte ' '|0x80
+#else /* SIO */
+item:		.ascii " ";	     .byte ' '|0x80
+prompt:		.ascii "\nDef:";     .byte ' '|0x80
+#endif /* SIO */
+crlf:		.ascii "\r";	     .byte '\n'|0x80
+
+// Partition type tables
+
+tables:
+//
+// These entries identify invalid or NON BOOT types and partitions.
+//
+		.byte 0x0, 0x5, 0xf
+//
+// These values indicate bootable types we know the names of
+//
+		.byte 0x1, 0x4, 0x6, 0xb, 0xc, 0xe, 0x83
+		.byte 0x9f, 0xa5, 0xa6, 0xa9
+//
+// These are offsets that match the known names above and point to the strings
+// that will be printed.
+//
+		.byte os_misc-. 		// Unknown
+		.byte os_dos-.			// DOS
+		.byte os_dos-.			// DOS
+		.byte os_dos-.			// DOS
+		.byte os_dos-.			// Windows
+		.byte os_dos-.			// Windows
+		.byte os_dos-.			// Windows
+		.byte os_linux-.		// Linux
+		.byte os_bsd-.			// BSD/OS
+		.byte os_freebsd-.		// FreeBSD
+		.byte os_bsd-.			// OpenBSD
+		.byte os_bsd-.			// NetBSD
+//
+// And here are the strings themselves. 0x80 or'd into a byte indicates
+// the end of the string. (not so great for Russians but...)
+//
+os_misc:	.ascii "?";    .byte '?'|0x80
+os_dos:		.ascii "DO";   .byte 'S'|0x80
+os_linux:	.ascii "Linu"; .byte 'x'|0x80
+os_freebsd:	.ascii "Free"
+os_bsd:		.ascii "BS";   .byte 'D'|0x80
+
+		.org PRT_OFF-0xe,0x90
+
+		.word B0MAGIC			// Magic number
+
+//
+// These values are sometimes changed before writing back to the drive
+// Be especially careful that nxtdrv: must come after drive:, as it
+// is part of the same string.
+//
+drive:		.ascii "Drive "
+nxtdrv:		.byte 0x0			// Next drive number
+opt:		.byte 0x0			// Option
+setdrv:		.byte 0x80			// Drive to force
+flags:		.byte FLAGS			// Flags
+ticks:		.word TICKS			// Delay
+
+//
+// here is the 64 byte partition table that fdisk would fiddle with.
+//
+partbl:		.fill 0x40,0x1,0x0		// Partition table
+		.word MAGIC			// Magic number
diff --git a/sys/boot/i386/boot0/boot0sio.s b/sys/boot/i386/boot0/boot0sio.s
deleted file mode 100644
index 62e6556..0000000
--- a/sys/boot/i386/boot0/boot0sio.s
+++ /dev/null
@@ -1,438 +0,0 @@
-#
-# Copyright (c) 2002 Bruce M. Simpson
-# Copyright (c) 1998 Robert Nordier
-# All rights reserved.
-#
-# Redistribution and use in source and binary forms are freely
-# permitted provided that the above copyright notice and this
-# paragraph and the following disclaimer are duplicated in all
-# such forms.
-#
-# This software is provided "AS IS" and without any express or
-# implied warranties, including, without limitation, the implied
-# warranties of merchantability and fitness for a particular
-# purpose.
-#
-
-# $FreeBSD$
-
-# A 512-byte boot manager which uses a serial console on COM1.
-
-		.set NHRDRV,0x475		# Number of hard drives
-		.set ORIGIN,0x600		# Execution address
-		.set FAKE,0x800 		# Partition entry
-		.set LOAD,0x7c00		# Load address
-
-		.set PRT_OFF,0x1be		# Partition table
-
-		.set TBL0SZ,0x3 		# Table 0 size
-		.set TBL1SZ,0xb 		# Table 1 size
-
-		.set MAGIC,0xaa55		# Magic: bootable
-		.set B0MAGIC,0xbb66		# Identification
-
-		.set KEY_ENTER,0x1c		# Enter key scan code
-		.set KEY_F1,0x3b		# F1 key scan code
-		.set KEY_1,0x02			# #1 key scan code
-
-		.set ASCII_BEL,0x07		# ASCII code for <BEL>
-		.set ASCII_CR,0x0D		# ASCII code for <CR>
-		.set ASCII_1,0x31		# ASCII code for '1'
-
-#
-# Addresses in the sector of embedded data values.
-# Accessed with negative offsets from the end of the relocated sector (%ebp).
-#
-		.set _NXTDRV,-0x48		# Next drive
-		.set _OPT,-0x47 		# Default option
-		.set _SETDRV,-0x46		# Drive to force
-		.set _FLAGS,-0x45		# Flags
-		.set _TICKS,-0x44		# Timeout ticks
-		.set _FAKE,0x0			# Fake partition entry
-		.set _MNUOPT,0xc		# Menu options
-
-		.globl start			# Entry point
-		.code16				# This runs in real mode
-
-#
-# Initialise segments and registers to known values.
-# segments start at 0.
-# The stack is immediately below the address we were loaded to.
-#
-start:		cld				# String ops inc
-		xorw %ax,%ax			# Zero
-		movw %ax,%es			# Address
-		movw %ax,%ds			#  data
-		movw %ax,%ss			# Set up
-		movw $LOAD,%sp			#  stack
-
-#
-# Copy this code to the address it was linked for
-#
-		movw %sp,%si			# Source
-		movw $start,%di			# Destination
-		movw $0x100,%cx			# Word count
-		rep				# Relocate
-		movsw				#  code
-#
-# Set address for variable space beyond code, and clear it.
-# Notice that this is also used to point to the values embedded in the block,
-# by using negative offsets.
-#
-		movw %di,%bp			# Address variables
-		movb $0x8,%cl			# Words to clear
-		rep				# Zero
-		stosw				#  them
-#
-# Relocate to the new copy of the code.
-#
-		incb -0xe(%di)			# Sector number
-		jmp main-LOAD+ORIGIN		# To relocated code
-
-#
-# Initialize the serial port.
-# Must save DX (contains drive number)
-#
-main:		pushw %dx			# Save
-		xorw %dx,%dx			# Port: COM1
-		movb COMSPEED,%al		# defined by Makefile
-		movb $0x00,%ah			# BIOS: Set COM Port
-		int $0x14			#  Parameters
-		popw %dx			# Restore
-#
-# Check what flags were loaded with us, specifically, Use a predefined Drive.
-# If what the bios gives us is bad, use the '0' in the block instead, as well.
-#
-		testb $0x20,_FLAGS(%bp)		# Set number drive?
-		jnz main.1			# Yes
-		testb %dl,%dl			# Drive number valid?
-		js main.2			# Possibly (0x80 set)
-main.1:		movb _SETDRV(%bp),%dl		# Drive number to use
-#
-# Whatever we decided to use, now store it into the fake
-# partition entry that lives in the data space above us.
-#
-main.2:		movb %dl,_FAKE(%bp)		# Save drive number
-		callw putn			# To new line
-		pushw %dx			# Save drive number
-#
-# Start out with a pointer to the 4th byte of the first table entry
-# so that after 4 iterations it's beyond the end of the sector.
-# and beyond a 256 byte boundary and has overflowed 8 bits (see next comment).
-# (remember that the table starts 2 bytes earlier than you would expect
-# as the bootable flag is after it in the block)
-#
-		movw $(partbl+0x4),%bx		# Partition table (+4)
-		xorw %dx,%dx			# Item number
-#
-# Loop around on the partition table, printing values until we
-# pass a 256 byte boundary. The end of loop test is at main.5.
-#
-main.3:		movb %ch,-0x4(%bx)		# Zero active flag (ch == 0)
-		btw %dx,_FLAGS(%bp)		# Entry enabled?
-		jnc main.5			# No
-#
-# If any of the entries in the table are
-# the same as the 'type' in the slice table entry,
-# then this is an empty or non bootable partition. Skip it.
-#
-		movb (%bx),%al			# Load type
-		movw $tables,%di		# Lookup tables
-		movb $TBL0SZ,%cl		# Number of entries
-		repne				# Exclude
-		scasb				#  partition?
-		je main.5			# Yes
-#
-# Now scan the table of known types
-#
-		movb $TBL1SZ,%cl		# Number of entries
-		repne				# Known
-		scasb				#  type?
-		jne main.4			# No
-#
-# If it matches get the matching element in the
-# next array. if it doesn't, we are already
-# pointing at its first element which points to a "?".
-#
-		addw $TBL1SZ,%di		# Adjust
-main.4:		movb (%di),%cl			# Partition
-		addw %cx,%di			#  description
-		callw putx			# Display it
-main.5:		incw %dx			# Next item
-		addb $0x10,%bl			# Next entry
-		jnc main.3			# Till done
-#
-# Passed a 256 byte boundary..
-# table is finished.
-# Add one to the drive number and check it is valid,
-#
-		popw %ax			# Drive number
-		subb $0x80-0x1,%al		# Does next
-		cmpb NHRDRV,%al			#  drive exist? (from BIOS?)
-		jb main.6			# Yes
-# If not then if there is only one drive,
-# Don't display drive as an option.
-#
-		decw %ax			# Already drive 0?
-		jz main.7			# Yes
-# If it was illegal or we cycled through them,
-# then go back to drive 0.
-#
-		xorb %al,%al			# Drive 0
-#
-# Whatever drive we selected, make it an ascii digit and save it back
-# to the "next drive" location in the loaded block in case we
-# want to save it for next time.
-# This also is part of the printed drive string so add 0x80 to indicate
-# end of string.
-#
-main.6:		addb $'0'|0x80,%al		# Save next
-		movb %al,_NXTDRV(%bp)		#  drive number
-		movw $drive,%di			# Display
-		callw putx			#  item
-#
-# Now that we've printed the drive (if we needed to), display a prompt.
-# Get ready for the input byte noting the time.
-#
-main.7:		movw $prompt,%si		# Display
-		callw putstr			#  prompt
-		movb _OPT(%bp),%dl		# Display
-		decw %si			#  default
-		callw putkey			#  key
-main.7_1:
-		xorb %ah,%ah			# BIOS: Get
-		int $0x1a			#  system time
-		movw %dx,%si			# Ticks when
-		addw _TICKS(%bp),%si		#  timeout
-
-#
-# Busy loop, checking for a character on the serial port, but
-# keeping one eye on the time.
-#
-
-main.8:		xorw %dx,%dx			# Use COM1
-		movb $0x03,%ah			# BIOS: Read COM
-		int $0x14			#  Status
-		testb $0x01,%ah			# Check line status
-		jnz main.11 			# (bit 1 indicates input)
-
-		xorb %ah,%ah			# BIOS: Get
-		int $0x1a			#  system time
-		cmpw %si,%dx			# Timeout?
-		jb main.8			# No
-
-#
-# If timed out or defaulting, come here.
-#
-main.9:		movb _OPT(%bp),%al		# Load default
-		jmp main.12			# Join common code
-#
-# User's last try was bad, beep in displeasure.
-# Since nothing was printed, just continue on as if the user
-# hadn't done anything. This gives the effect of the user getting a beep
-# for all bad keystrokes but no action until either the timeout
-# occurs or the user hits a good key.
-#
-main.10:	movb $ASCII_BEL,%al		# Signal
-		callw putchr			#  error
-		jmp main.7_1			# Go back
-#
-# Check the character we just got on the serial port.
-#
-main.11:	movb $0x02,%ah			# BIOS: Receive
-		int $0x14			#  COM Byte
-#
-# If it's CR act as if timed out.
-#
-		cmpb $ASCII_CR,%al		# Enter pressed?
-		je main.9			# Yes
-#
-# Otherwise check if legal
-# If not ask again.
-#
-		subb $ASCII_1,%al		# Less '1' ascii character
-		cmpb $0x4,%al			# #1..#5?
-		ja main.10			# No
-#
-# We have a selection.
-# but if it's a bad selection go back to complain.
-# The bits in MNUOPT were set when the options were printed.
-# Anything not printed is not an option.
-#
-main.12:	cbtw				# Option
-		btw %ax,_MNUOPT(%bp)	 	#  enabled?
-		jnc main.10			# No
-#
-# Save the info in the original tables
-# for rewriting to the disk.
-#
-		movb %al,_OPT(%bp)		# Save option
-		movw $FAKE,%si			# Partition for write
-		movb (%si),%dl			# Drive number
-		movw %si,%bx			# Partition for read
-		cmpb $0x4,%al			# F5/#5 pressed?
-		pushf				# Save
-		je main.13			# Yes
-		shlb $0x4,%al			# Point to
-		addw $partbl,%ax		#  selected
-		xchgw %bx,%ax	 		#  partition
-		movb $0x80,(%bx)		# Flag active
-#
-# If not asked to do a write-back (flags 0x40) don't do one.
-#
-main.13:	pushw %bx			# Save
-		testb $0x40,_FLAGS(%bp)		# No updates?
-		jnz main.14			# Yes
-		movw $start,%bx			# Data to write
-		movb $0x3,%ah			# Write sector
-		callw intx13			#  to disk
-main.14:	popw %si			# Restore
-		popf				# Restore
-#
-# If going to next drive, replace drive with selected one.
-# Remember to un-ascii it. Hey 0x80 is already set, cool!
-#
-		jne main.15			# If not F5/#5
-		movb _NXTDRV(%bp),%dl		# Next drive
-		subb $'0',%dl			#  number
-#
-# load  selected bootsector to the LOAD location in RAM.
-# If it fails to read or isn't marked bootable, treat it
-# as a bad selection.
-# XXX what does %si carry?
-#
-main.15:	movw $LOAD,%bx			# Address for read
-		movb $0x2,%ah			# Read sector
-		callw intx13			#  from disk
-		jc main.10			# If error
-		cmpw $MAGIC,0x1fe(%bx)		# Bootable?
-		jne main.10			# No
-		pushw %si			# Save
-		movw $crlf,%si			# Leave some
-		callw puts			#  space
-		popw %si			# Restore
-		jmp *%bx			# Invoke bootstrap
-#
-# Display routines
-#
-
-putkey:		movb $ASCII_1,%al		# Prepare
-		addb %dl,%al			#  digit
-		jmp putstr.1			# Display the rest
-
-#
-# Display the option and note that it is a valid option.
-# That last point is a bit tricky..
-#
-putx:		btsw %dx,_MNUOPT(%bp)		# Enable menu option
-		movw $item,%si			# Display
-		callw putkey			#  key
-		movw %di,%si			# Display the rest
-
-puts:		callw putstr			# Display string
-
-putn:		movw $crlf,%si			# To next line
-
-putstr:		lodsb				# Get byte
-		testb $0x80,%al 		# End of string?
-		jnz putstr.2			# Yes
-putstr.1:	callw putchr			# Display char
-		jmp putstr			# Continue
-putstr.2:	andb $~0x80,%al 		# Clear MSB
-
-putchr:		pushw %dx			# Save
-		xorw %dx,%dx 			# Use COM1
-		xorw %cx,%cx 			# No timeout
-		movb $0x01,%ah			# BIOS: Send
-		int $0x14			#  Character
-		popw %dx			# Restore
-		retw				# To caller
-
-# One-sector disk I/O routine
-
-intx13:		movb 0x1(%si),%dh		# Load head
-		movw 0x2(%si),%cx		# Load cylinder:sector
-		movb $0x1,%al			# Sector count
-		pushw %si			# Save
-		movw %sp,%di			# Save
-		testb $0x80,_FLAGS(%bp)		# Use packet interface?
-		jz intx13.1			# No
-		pushl $0x0			# Set the
-		pushl 0x8(%si)			# LBA address
-		pushw %es			# Set the transfer
-		pushw %bx			#  buffer address
-		push  $0x1			# Block count
-		push  $0x10			# Packet size
-		movw %sp,%si			# Packet pointer
-		decw %ax			# Verify off
-		orb $0x40,%ah			# Use disk packet
-intx13.1:	int $0x13			# BIOS: Disk I/O
-		movw %di,%sp			# Restore
-		popw %si			# Restore
-		retw				# To caller
-
-# Menu strings
-
-item:		.ascii " ";	     .byte ' '|0x80
-prompt:		.ascii "\nDef:";     .byte ' '|0x80
-crlf:		.ascii "\r";	     .byte '\n'|0x80
-
-# Partition type tables
-
-tables:
-#
-# These entries identify invalid or NON BOOT types and partitions.
-#
-		.byte 0x0, 0x5, 0xf
-#
-# These values indicate bootable types we know the names of
-#
-		.byte 0x1, 0x4, 0x6, 0xb, 0xc, 0xe, 0x83
-		.byte 0x9f, 0xa5, 0xa6, 0xa9
-#
-# These are offsets that match the known names above and point to the strings
-# that will be printed.
-#
-		.byte os_misc-. 		# Unknown
-		.byte os_dos-.			# DOS
-		.byte os_dos-.			# DOS
-		.byte os_dos-.			# DOS
-		.byte os_dos-.			# Windows
-		.byte os_dos-.			# Windows
-		.byte os_dos-.			# Windows
-		.byte os_linux-.		# Linux
-		.byte os_bsd-.			# BSD/OS
-		.byte os_freebsd-.		# FreeBSD
-		.byte os_bsd-.			# OpenBSD
-		.byte os_bsd-.			# NetBSD
-#
-# And here are the strings themselves. 0x80 or'd into a byte indicates
-# the end of the string. (not so great for Russians but...)
-#
-os_misc:	.ascii "?";    .byte '?'|0x80
-os_dos:		.ascii "DO";   .byte 'S'|0x80
-os_linux:	.ascii "Linu"; .byte 'x'|0x80
-os_freebsd:	.ascii "Free"
-os_bsd:		.ascii "BS";   .byte 'D'|0x80
-
-		.org PRT_OFF-0xe,0x90
-
-		.word B0MAGIC			# Magic number
-
-#
-# These values are sometimes changed before writing back to the drive
-# Be especially careful that nxtdrv: must come after drive:, as it
-# is part of the same string.
-#
-drive:		.ascii "Drive "
-nxtdrv:		.byte 0x0			# Next drive number
-opt:		.byte 0x0			# Option
-setdrv:		.byte 0x80			# Drive to force
-flags:		.byte FLAGS			# Flags
-ticks:		.word TICKS			# Delay
-
-#
-# here is the 64 byte partition table that fdisk would fiddle with.
-#
-partbl:		.fill 0x40,0x1,0x0		# Partition table
-		.word MAGIC			# Magic number