+++ /dev/null
-# This code is no longer used in Etherboot. It is not maintained and
-# may not work.
-
-
-#
-# Copyright (c) 1998 Robert Nordier
-# All rights reserved.
-# Very small bootrom changes by Luigi Rizzo
-# <comment author="Luigi Rizzo">
-# I recently had the problem of downloading the etherboot code
-# from a hard disk partition instead of a floppy, and noticed that
-# floppyload.S does not do the job. With a bit of hacking to
-# the FreeBSD's boot1.s code, I managed to obtain a boot sector
-# which works both for floppies and hard disks -- basically you
-# do something like
-#
-# cat boot1a bin32/<yourcard>.lzrom > /dev/ad0s4
-#
-# (or whatever is the HD partition you are using, I am using slice
-# 4 on FreeBSD) and you are up and running.
-# Then with "fdisk" you have to mark your partition as having type "1"
-# (which is listed as DOS-- but basically it must be something matching
-# the variable PRT_BSD in the assembly source below).
-# </comment>
-#
-# 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.
-#
-# Makefile:
-#boot1a: boot1a.out
-# objcopy -S -O binary boot1a.out boot1a
-#
-#boot1a.out: boot1a.o
-# ld -nostdlib -static -N -e start -Ttext 0x7c00 -o boot1a.out boot1a.o
-#
-#boot1a.o: boot1a.s
-# as --defsym FLAGS=0x80 boot1a.s -o boot1a.o
-#
-#
-
-# $FreeBSD: src/sys/boot/i386/boot2/boot1.s,v 1.10.2.2 2000/07/07 21:12:32 jhb Exp $
-
-# Memory Locations
- .set MEM_REL,0x700 # Relocation address
- .set MEM_ARG,0x900 # Arguments
- .set MEM_ORG,0x7c00 # Origin
- .set MEM_BUF,0x8c00 # Load area
- .set MEM_BTX,0x9000 # BTX start
- .set MEM_JMP,0x9010 # BTX entry point
- .set MEM_USR,0xa000 # Client start
- .set BDA_BOOT,0x472 # Boot howto flag
-
-# Partition Constants
- .set PRT_OFF,0x1be # Partition offset
- .set PRT_NUM,0x4 # Partitions
- .set PRT_BSD,0x1 # Partition type
-
-# Flag Bits
- .set FL_PACKET,0x80 # Packet mode
-
-# Misc. Constants
- .set SIZ_PAG,0x1000 # Page size
- .set SIZ_SEC,0x200 # Sector size
-
- .globl start
- .globl xread
- .code16
-
-start: jmp main # Start recognizably
-
- .org 0x4,0x90
-#
-# Trampoline used by boot2 to call read to read data from the disk via
-# the BIOS. Call with:
-#
-# %cx:%ax - long - LBA to read in
-# %es:(%bx) - caddr_t - buffer to read data into
-# %dl - byte - drive to read from
-# %dh - byte - num sectors to read
-#
-
-xread: push %ss # Address
- pop %ds # data
-#
-# Setup an EDD disk packet and pass it to read
-#
-xread.1: # Starting
- pushl $0x0 # absolute
- push %cx # block
- push %ax # number
- push %es # Address of
- push %bx # transfer buffer
- xor %ax,%ax # Number of
- movb %dh,%al # blocks to
- push %ax # transfer
- push $0x10 # Size of packet
- mov %sp,%bp # Packet pointer
- callw read # Read from disk
- lea 0x10(%bp),%sp # Clear stack
- lret # To far caller
-#
-# Load the rest of boot2 and BTX up, copy the parts to the right locations,
-# and start it all up.
-#
-
-#
-# Setup the segment registers to flat addressing (segment 0) and setup the
-# stack to end just below the start of our code.
-#
-main: cld # String ops inc
- xor %cx,%cx # Zero
- mov %cx,%es # Address
- mov %cx,%ds # data
- mov %cx,%ss # Set up
- mov $start,%sp # stack
-#
-# Relocate ourself to MEM_REL. Since %cx == 0, the inc %ch sets
-# %cx == 0x100.
-#
- mov %sp,%si # Source
- mov $MEM_REL,%di # Destination
- incb %ch # Word count
- rep # Copy
- movsw # code
-#
-# If we are on a hard drive, then load the MBR and look for the first
-# FreeBSD slice. We use the fake partition entry below that points to
-# the MBR when we call nread. The first pass looks for the first active
-# FreeBSD slice. The second pass looks for the first non-active FreeBSD
-# slice if the first one fails.
-#
- mov $part4,%si # Partition
- cmpb $0x80,%dl # Hard drive?
- jb main.4 # No
- movb $0x1,%dh # Block count
- callw nread # Read MBR
- mov $0x1,%cx # Two passes
-main.1: mov $MEM_BUF+PRT_OFF,%si # Partition table
- movb $0x1,%dh # Partition
-main.2: cmpb $PRT_BSD,0x4(%si) # Our partition type?
- jne main.3 # No
- jcxz main.5 # If second pass
- testb $0x80,(%si) # Active?
- jnz main.5 # Yes
-main.3: add $0x10,%si # Next entry
- incb %dh # Partition
- cmpb $0x1+PRT_NUM,%dh # In table?
- jb main.2 # Yes
- dec %cx # Do two
- jcxz main.1 # passes
-#
-# If we get here, we didn't find any FreeBSD slices at all, so print an
-# error message and die.
-#
-booterror: mov $msg_part,%si # Message
- jmp error # Error
-#
-# Floppies use partition 0 of drive 0.
-#
-main.4: xor %dx,%dx # Partition:drive
-#
-# Ok, we have a slice and drive in %dx now, so use that to locate and load
-# boot2. %si references the start of the slice we are looking for, so go
-# ahead and load up the first 16 sectors (boot1 + boot2) from that. When
-# we read it in, we conveniently use 0x8c00 as our transfer buffer. Thus,
-# boot1 ends up at 0x8c00, and boot2 starts at 0x8c00 + 0x200 = 0x8e00.
-# The first part of boot2 is the disklabel, which is 0x200 bytes long.
-# The second part is BTX, which is thus loaded into 0x9000, which is where
-# it also runs from. The boot2.bin binary starts right after the end of
-# BTX, so we have to figure out where the start of it is and then move the
-# binary to 0xb000. Normally, BTX clients start at MEM_USR, or 0xa000, but
-# when we use btxld create boot2, we use an entry point of 0x1000. That
-# entry point is relative to MEM_USR; thus boot2.bin starts at 0xb000.
-#
-main.5: mov %dx,MEM_ARG # Save args
- movb $0x2,%dh # Sector count
- mov $0x7e00, %bx
- callw nreadbx # Read disk
- movb $0x40,%dh # Sector count
- movb %dh, %al
- callw puthex
- mov $0x7e00, %bx
- callw nreadbx # Read disk
- push %si
- mov $msg_r1,%si
- callw putstr
- pop %si
- lcall $0x800,$0 # enter the rom code
- int $0x19
-
-msg_r1: .asciz " done\r\n"
-
-.if 0
- mov $MEM_BTX,%bx # BTX
- mov 0xa(%bx),%si # Get BTX length and set
- add %bx,%si # %si to start of boot2.bin
- mov $MEM_USR+SIZ_PAG,%di # Client page 1
- mov $MEM_BTX+0xe*SIZ_SEC,%cx # Byte
- sub %si,%cx # count
- rep # Relocate
- movsb # client
- sub %di,%cx # Byte count
- xorb %al,%al # Zero assumed bss from
- rep # the end of boot2.bin
- stosb # up to 0x10000
- callw seta20 # Enable A20
- jmp start+MEM_JMP-MEM_ORG # Start BTX
-#
-# Enable A20 so we can access memory above 1 meg.
-#
-seta20: cli # Disable interrupts
-seta20.1: inb $0x64,%al # Get status
- testb $0x2,%al # Busy?
- jnz seta20.1 # Yes
- movb $0xd1,%al # Command: Write
- outb %al,$0x64 # output port
-seta20.2: inb $0x64,%al # Get status
- testb $0x2,%al # Busy?
- jnz seta20.2 # Yes
- movb $0xdf,%al # Enable
- outb %al,$0x60 # A20
- sti # Enable interrupts
- retw # To caller
-.endif
-#
-# Trampoline used to call read from within boot1.
-#
-nread: mov $MEM_BUF,%bx # Transfer buffer
-nreadbx: # same but address is in bx
- mov 0x8(%si),%ax # Get
- mov 0xa(%si),%cx # LBA
- push %bx
- push %ax
- callw putword
- pop %ax
- pop %bx
- push %cs # Read from
- callw xread.1 # disk
- jnc return # If success, return
- mov $msg_read,%si # Otherwise, set the error
- # message and fall through to
- # the error routine
-#
-# Print out the error message pointed to by %ds:(%si) followed
-# by a prompt, wait for a keypress, and then reboot the machine.
-#
-error: callw putstr # Display message
- mov $prompt,%si # Display
- callw putstr # prompt
- xorb %ah,%ah # BIOS: Get
- int $0x16 # keypress
- movw $0x1234, BDA_BOOT # Do a warm boot
- ljmp $0xffff,$0x0 # reboot the machine
-#
-# Display a null-terminated string using the BIOS output.
-#
-putstr.0: call putchar
-putstr: lodsb # Get char
- testb %al,%al # End of string?
- jne putstr.0 # No
- retw
-
-putword: push %ax
- movb $'.', %al
- callw putchar
- movb %ah, %al
- callw puthex
- pop %ax
-puthex: push %ax
- shr $4, %al
- callw putdigit
- pop %ax
-putdigit:
- andb $0xf, %al
- addb $0x30, %al
- cmpb $0x39, %al
- jbe putchar
- addb $7, %al
-putchar: push %ax
- mov $0x7,%bx
- movb $0xe,%ah
- int $0x10
- pop %ax
- retw
-
-#
-# Overused return code. ereturn is used to return an error from the
-# read function. Since we assume putstr succeeds, we (ab)use the
-# same code when we return from putstr.
-#
-ereturn: movb $0x1,%ah # Invalid
- stc # argument
-return: retw # To caller
-#
-# Reads sectors from the disk. If EDD is enabled, then check if it is
-# installed and use it if it is. If it is not installed or not enabled, then
-# fall back to using CHS. Since we use a LBA, if we are using CHS, we have to
-# fetch the drive parameters from the BIOS and divide it out ourselves.
-# Call with:
-#
-# %dl - byte - drive number
-# stack - 10 bytes - EDD Packet
-#
-read: push %dx # Save
- movb $0x8,%ah # BIOS: Get drive
- int $0x13 # parameters
- movb %dh,%ch # Max head number
- pop %dx # Restore
- jc return # If error
- andb $0x3f,%cl # Sectors per track
- jz ereturn # If zero
- cli # Disable interrupts
- mov 0x8(%bp),%eax # Get LBA
- push %dx # Save
- movzbl %cl,%ebx # Divide by
- xor %edx,%edx # sectors
- div %ebx # per track
- movb %ch,%bl # Max head number
- movb %dl,%ch # Sector number
- inc %bx # Divide by
- xorb %dl,%dl # number
- div %ebx # of heads
- movb %dl,%bh # Head number
- pop %dx # Restore
- cmpl $0x3ff,%eax # Cylinder number supportable?
- sti # Enable interrupts
- ja read.7 # No, try EDD
- xchgb %al,%ah # Set up cylinder
- rorb $0x2,%al # number
- orb %ch,%al # Merge
- inc %ax # sector
- xchg %ax,%cx # number
- movb %bh,%dh # Head number
- subb %ah,%al # Sectors this track
- mov 0x2(%bp),%ah # Blocks to read
- cmpb %ah,%al # To read
- jb read.2 # this
- movb %ah,%al # track
-read.2: mov $0x5,%di # Try count
-read.3: les 0x4(%bp),%bx # Transfer buffer
- push %ax # Save
- movb $0x2,%ah # BIOS: Read
- int $0x13 # from disk
- pop %bx # Restore
- jnc read.4 # If success
- dec %di # Retry?
- jz read.6 # No
- xorb %ah,%ah # BIOS: Reset
- int $0x13 # disk system
- xchg %bx,%ax # Block count
- jmp read.3 # Continue
-read.4: movzbw %bl,%ax # Sectors read
- add %ax,0x8(%bp) # Adjust
- jnc read.5 # LBA,
- incw 0xa(%bp) # transfer
-read.5: shlb %bl # buffer
- add %bl,0x5(%bp) # pointer,
- sub %al,0x2(%bp) # block count
- ja read # If not done
-read.6: retw # To caller
-read.7: testb $FL_PACKET,%cs:MEM_REL+flags-start # LBA support enabled?
- jz ereturn # No, so return an error
- mov $0x55aa,%bx # Magic
- push %dx # Save
- movb $0x41,%ah # BIOS: Check
- int $0x13 # extensions present
- pop %dx # Restore
- jc return # If error, return an error
- cmp $0xaa55,%bx # Magic?
- jne ereturn # No, so return an error
- testb $0x1,%cl # Packet interface?
- jz ereturn # No, so return an error
- mov %bp,%si # Disk packet
- movb $0x42,%ah # BIOS: Extended
- int $0x13 # read
- retw # To caller
-
-# Messages
-
-msg_read: .asciz "Rd"
-msg_part: .asciz "Boot"
-
-prompt: .asciz " err\r\n"
-
-flags: .byte FLAGS # Flags
-
- .org PRT_OFF,0x90
-
-# Partition table
-
- .fill 0x30,0x1,0x0
-part4: .byte 0x80
- .byte 0x00 # start head
- .byte 0x01 # start sector (6 bits) + start cyl (2 bit)
- .byte 0x00 # start cyl (low 8 bits)
- .byte 0x1 # part.type
- .byte 0xff # end head
- .byte 0xff # end sect (6) + end_cyl(2)
- .byte 0xff # end cyl
- .byte 0x00, 0x00, 0x00, 0x00 # explicit start
- .byte 0x50, 0xc3, 0x00, 0x00 # 50000 sectors long, bleh
-
- .word 0xaa55 # Magic number
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