-; Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
+; Copyright (c) 1999-2002 Apple Computer, Inc. All rights reserved.
;
; @APPLE_LICENSE_HEADER_START@
;
-; Portions Copyright (c) 1999 Apple Computer, Inc. All Rights
-; Reserved. This file contains Original Code and/or Modifications of
-; Original Code as defined in and that are subject to the Apple Public
-; Source License Version 1.1 (the "License"). You may not use this file
-; except in compliance with the License. Please obtain a copy of the
-; License at http://www.apple.com/publicsource and read it before using
-; this file.
+; Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
+;
+; This file contains Original Code and/or Modifications of Original Code
+; as defined in and that are subject to the Apple Public Source License
+; Version 2.0 (the 'License'). You may not use this file except in
+; compliance with the License. Please obtain a copy of the License at
+; http://www.opensource.apple.com/apsl/ and read it before using this
+; file.
;
; The Original Code and all software distributed under the License are
-; distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+; distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
; EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
; INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
-; FITNESS FOR A PARTICULAR PURPOSE OR NON- INFRINGEMENT. Please see the
-; License for the specific language governing rights and limitations
-; under the License.
+; FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+; Please see the License for the specific language governing rights and
+; limitations under the License.
;
; @APPLE_LICENSE_HEADER_END@
;
-; Boot Loader: boot0
+; Partition Boot Loader: boot1h
;
-; A small boot sector program written in x86 assembly whose only
-; responsibility is to locate the booter partition, load the
-; booter into memory, and jump to the booter's entry point.
-; The booter partition can be a primary or a logical partition.
-; But the booter partition must reside within the 8GB limit
-; imposed by CHS addressing + translation.
+; This program is designed to reside in sector 0 of an HFS+ partition.
+; The HFS+ partition can be a primary or a logical partition.
+; It expects that the MBR has left the drive number in DL
+; and a pointer to the partition entry in SI.
;
-; This boot loader can be placed at any of the following places:
-; * Master Boot Record (MBR)
-; * Boot sector of an extended partition
-; * Boot sector of a primary partition
-; * Boot sector of a logical partition
-;
-; In order to coexist with a fdisk partition table (64 bytes), and
-; leave room for a two byte signature (0xAA55) in the end, boot0 is
-; restricted to 446 bytes (512 - 64 - 2). If boot0 did not have to
-; live in the MBR, then we would have 510 bytes to play with.
-;
-; boot0 is always loaded by the BIOS or another first level booter
-; to 0:7C00h.
+; This version requires a BIOS with EBIOS (LBA) support.
;
; This code is written for the NASM assembler.
; nasm boot0.s -o boot0
-;--------------------------------------------------------------------------
-; Constants.
-FLOPPY EQU 0x00 ; floppy dev number
-HDISK EQU 0x80 ; hard drive dev number
-DEBUG EQU 0 ; enable debugging output
+;
+; Set to 1 to enable obscure debug messages.
+;
+DEBUG EQU 0
-BOOTSEG EQU 0x0 ; our sole segment
-BOOTSP EQU 0xFFF0 ; stack pointer
-BOOTLOAD EQU 0x7C00 ; booter load address
-BOOTRELOC EQU 0xE000 ; booter is relocated here
-BOOTSIG EQU 0xAA55 ; booter signature
+;
+; Set to 1 to support loading the booter (boot2) from a
+; logical partition.
+;
+EXT_PART_SUPPORT EQU 0
-BOOT2_SIZE EQU 88 ; load this many blocks for boot2
-BOOT2_ADDR EQU 0x3000 ; where to load boot2
+;
+; Various constants.
+;
+kBoot0Segment EQU 0x0000
+kBoot0Stack EQU 0xFFF0 ; boot0 stack pointer
+kBoot0LoadAddr EQU 0x7C00 ; boot0 load address
+kBoot0RelocAddr EQU 0xE000 ; boot0 relocated address
-%IF BOOTDEV = FLOPPY
-DRIVE_NUM EQU FLOPPY ; floppy drive
-%ELSE
-DRIVE_NUM EQU HDISK ; "C" drive
-%ENDIF
-SECTOR_BYTES EQU 512 ; sector size in bytes
+ebios_lba EQU 0xEF00 ; storage for variables
-BUF_MBR EQU 0x1000 ; memory buffer for MBR
-BUF_EXT EQU 0x1200 ; memory buffer for extended partition
+kMBRBuffer EQU 0x1000 ; MBR buffer address
+kExtBuffer EQU 0x1200 ; EXT boot block buffer address
-TABLE_MAIN EQU BUF_MBR + 0x1be ; location of main partition table
-TABLE_EXT EQU BUF_EXT + 0x1be ; location of ext partition table
-ENTRY_SIZE EQU 16 ; size of each fdisk partition entry
-TYPE_BOOT EQU 0xab ; partition type we are looking for
-TYPE_EXT EQU 0x05 ; extended partition type
-TYPE_EXT_1 EQU 0x0f ; Windows extended partition
-TYPE_EXT_2 EQU 0x85 ; Linux extended partition
-EXT_LEVELS_MAX EQU 128 ; max extended partition levels
+kPartTableOffset EQU 0x1be
+kMBRPartTable EQU kMBRBuffer + kPartTableOffset
+kExtPartTable EQU kExtBuffer + kPartTableOffset
+kBoot2Sectors EQU 112 ; sectors to load for boot2
+kBoot2Address EQU 0x0000 ; boot2 load address
+kBoot2Segment EQU 0x2000 ; boot2 load segment
-;--------------------------------------------------------------------------
-; Start of text segment.
+kSectorBytes EQU 512 ; sector size in bytes
+kBootSignature EQU 0xAA55 ; boot sector signature
- SEGMENT .text
+kPartCount EQU 4 ; number of paritions per table
+kPartTypeBoot EQU 0xab ; boot2 partition type
+kPartTypeHFS EQU 0xaf
+kPartTypeExtDOS EQU 0x05 ; DOS extended partition type
+kPartTypeExtWin EQU 0x0f ; Windows extended partition type
+kPartTypeExtLinux EQU 0x85 ; Linux extended partition type
+
+kPartActive EQU 0x80
+
+;;
+;; HFS constants
+;;
+kHFSSig EQU 0x4442 ; HFS volume signature
+kAlBlStOffset EQU 0x1c
+kEmbedStartOffset EQU 0x7e
+kAlBlkSizOffset EQU 0x14
+
+;;
+;; HFS+ constants
+;;
+kHFSPlusSig EQU 0x2B48 ; HFS+ volume signature
+kBlockSizeOffset EQU 0x28
+kExtentOffset EQU 0x1c0
+
+kHFSBuffer EQU 0x1400 ; HFS volume header address
- ORG 0xE000 ; must match BOOTRELOC
+kHFSSigAddr EQU kHFSBuffer
+kHFSAlBlSt EQU kHFSBuffer + kAlBlStOffset
+kHFSEmbedStart EQU kHFSBuffer + kEmbedStartOffset
+kHFSAlBlkSiz EQU kHFSBuffer + kAlBlkSizOffset
-;--------------------------------------------------------------------------
-; Loaded at 0:7c00h.
-;
-start
- ; Set up the stack to grow down from BOOTSEG:BOOTSP.
- ; Interrupts should be off while the stack is being manipulated.
- ;
- cli ; interrupts off
- mov ax, BOOTSEG ;
- mov ss, ax ; ss <- BOOTSEG
- mov sp, BOOTSP ; sp <- BOOTSP
- sti ; reenable interrupts
+kHFSPlusSigAddr EQU kHFSBuffer
+kHFSPlusBlockSize EQU kHFSBuffer + kBlockSizeOffset
+kHFSPlusExtent EQU kHFSBuffer + kExtentOffset
- ; Relocate the booter code from DS:SI to ES:DI,
- ; or from 0:7C00h to BOOTSEG:BOOTRELOC.
- ;
- mov es, ax ; es <- BOOTSEG
- xor ax, ax
- mov ds, ax ; ds <- 0
- mov si, BOOTLOAD ; si <- BOOTLOAD (source)
- mov di, BOOTRELOC ; di <- BOOTRELOC (destination)
- ;
- cld ; auto-increment SI and/or DI registers
- mov cx, 256 ; copy 256 words (512 bytes)
- repnz movsw ; repeat string move (word) operation
- ; Code relocated, jump to start_reloc in relocated location.
- ;
- jmp BOOTSEG:start_reloc
+%ifdef FLOPPY
+kDriveNumber EQU 0x00
+%else
+kDriveNumber EQU 0x80
+%endif
-;--------------------------------------------------------------------------
-; Start execution from the relocated location.
;
-start_reloc
- mov ax, BOOTSEG
- mov ds, ax ; ds <- BOOTSEG
-
- mov al, '=' ; indicate execution start
- call putchar
-
- ; Get disk parameters (CHS) using INT13/F8 call.
- ;
- mov dl, DRIVE_NUM ; boot drive is drive C
- mov ah, 8 ; Read Disk Driver Parameter function
- int 0x13
- and cl, 0x3f ; sectors/track
- mov [max_sectors], cl
- mov [max_heads], dh
- jc error
+; Format of fdisk partition entry.
+;
+; The symbol 'part_size' is automatically defined as an `EQU'
+; giving the size of the structure.
+;
+ struc part
+.bootid: resb 1 ; bootable or not
+.head: resb 1 ; starting head, sector, cylinder
+.sect: resb 1 ;
+.cyl: resb 1 ;
+.type: resb 1 ; partition type
+.endhead resb 1 ; ending head, sector, cylinder
+.endsect: resb 1 ;
+.endcyl: resb 1 ;
+.lba: resd 1 ; starting lba
+.sectors resd 1 ; size in sectors
+ endstruc
- mov al, '>' ; indicate INT13/F8 success
- call putchar
+;
+; Macros.
+;
+%macro DebugCharMacro 1
+ mov al, %1
+ call print_char
+ call getc
+%endmacro
- mov ax, BOOTSEG ; es <- BOOTSEG
- mov es, ax
+%if DEBUG
+%define DebugChar(x) DebugCharMacro x
+%else
+%define DebugChar(x)
+%endif
- ; Since this code may not always reside in the MBR, we will always
- ; start by loading the MBR to BUF_MBR.
- ;
- mov WORD [chs_cx], 0x0001 ; cyl = 0, sect = 1
- mov BYTE [chs_dx + 1], 0 ; head = 0
- xor cx, cx ; skip 0 sectors
- mov ax, 1 ; read 1 sector
- mov bx, BUF_MBR ; load buffer
- call load
- jc error
+
+;--------------------------------------------------------------------------
+; Start of text segment.
- mov di, TABLE_MAIN ; argument for find_booter
- cmp WORD [di + 64], BOOTSIG ; correct signature found?
- jne error ; Oops! no signature!
- mov bl, TYPE_BOOT ; look for this partition type
- mov bh, 0 ; initial nesting level is 0
- call find_booter
+ SEGMENT .text
-error
- mov si, load_error
- call message
-hang_1
- jmp hang_1
+ ORG 0xE000 ; must match kBoot0RelocAddr
;--------------------------------------------------------------------------
-; Locate the booter partition and load the booter.
-;
-; Arguments:
-; di - pointer to fdisk partition table.
-; bl - partition type to look for.
-;
-; The following registers are modified:
-; ax, bh
+; Boot code is loaded at 0:7C00h.
;
-find_booter
- push cx
- push si
-
- mov si, di ; si <- pointer to partition table
- mov cx, 4 ; 4 partition entries per table
-
-find_booter_pri
+start
;
- ; Hunt for a fdisk partition type that matches the value in bl.
+ ; Set up the stack to grow down from kBoot0Segment:kBoot0Stack.
+ ; Interrupts should be off while the stack is being manipulated.
;
-%IF DEBUG
- mov al, bh ; log partition type seen
- call putspace
- mov al, [si + 4]
- call display_byte
-%ENDIF
-
- cmp BYTE [si + 4], bl ; Is this the booter partition?
- je load_booter ; yes, load the booter
+ cli ; interrupts off
+ xor ax, ax ; zero ax
+ mov ss, ax ; ss <- 0
+ mov sp, kBoot0Stack ; sp <- top of stack
+ sti ; reenable interrupts
- add si, ENTRY_SIZE ; si <- next partition entry
- loop find_booter_pri ; loop while cx is not zero
+ mov es, ax ; es <- 0
+ mov ds, ax ; ds <- 0
- ; No primary (or perhaps logical) booter partition found in the
- ; current partition table. Restart and look for extended partitions.
- ;
- mov si, di ; si <- pointer to partition table
- mov cx, 4 ; 4 partition entries per table
+ DebugChar('H')
-find_booter_ext
- ;
- ; Look for extended partition entries in the partition table.
- ;
-%IF DEBUG
- mov al, bh ; log partition type seen
- call putspace
- mov al, 'E'
- call putchar
- mov al, [si + 4]
- call display_byte
-%ENDIF
-
- cmp BYTE [si + 4], TYPE_EXT ; Is this an extended partition?
- je find_booter_ext_2 ; yes, load its partition table
-
- cmp BYTE [si + 4], TYPE_EXT_1 ; Is this an extended partition?
- je find_booter_ext_2 ; yes, load its partition table
-
- cmp BYTE [si + 4], TYPE_EXT_2 ; Is this an extended partition?
- je find_booter_ext_2 ; yes, load its partition table
+%if DEBUG
+ mov eax, [si + part.lba]
+ call print_hex
+%endif
-find_booter_ext_1
;
- ; si is not pointing to an extended partition entry,
- ; try the next entry in the partition table.
+ ; Clear various flags in memory.
;
- add si, ENTRY_SIZE ; si <- next partition entry
- loop find_booter_ext ; loop while cx is not zero
-
- jmp find_booter_end ; give up
-
-find_booter_ext_2
- cmp bh, EXT_LEVELS_MAX
- ja find_booter_end ; in too deep!
+ xor eax, eax
+ mov [ebios_lba], eax ; clear EBIOS LBA offset
- inc bh ; increment nesting level counter
+ cmp BYTE [si + part.type], kPartTypeHFS
+ jne .part_err
+ cmp BYTE [si + part.bootid], kPartActive
+ jne .part_err
- ; Prepare the arguments for the load function call to
- ; load the extended partition table into memory.
- ; Note that si points to the extended partition entry.
- ;
- mov ax, [si] ; DH/DL
- mov [chs_dx], ax
- mov ax, [si + 2] ; CH/CL
- mov [chs_cx], ax
- pusha
- xor cx, cx ; skip 0 sectors
- mov ax, 1 ; read 1 sector
- mov bx, BUF_EXT ; load to BUF_EXT
+ jmp find_startup
+
+.part_err:
+ DebugChar('P')
+ jmp hang
+
+;;; ---------------------------------------
+;;;
+;;; find_startup - Find HFS+ startup file in a partition.
+;;;
+;;; Arguments:
+;;; DL = drive number (0x80 + unit number)
+;;; SI = pointer to the partition entry.
+;;;
+;;; On success, loads booter and jumps to it.
+;;;
+find_startup:
+ DebugChar(']')
+
+ mov al, 1 ; read 1 sector
+ xor bx, bx
+ mov es, bx ; es = 0
+ mov bx, kHFSBuffer ; load volume header
+ mov ecx, DWORD 2
call load
- popa
-
- jc find_booter_ext_3 ; bail out if load failed
-
- mov di, TABLE_EXT ; di <- pointer to new partition table
- cmp WORD [di + 64], BOOTSIG
- jne find_booter_ext_3 ; OhOh! no signature!
-
- call find_booter ; recursion...
-
-find_booter_ext_3
- dec bh ; decrement nesting level counter
-
- ; If we got here, then we know there isn't a booter
- ; partition linked from this partition entry.
+ jnc .ok ; load error
+
+ jmp startup_err
+
+.ok
+ mov ax, [kHFSSigAddr]
+ cmp ax, kHFSSig
+ jne .hfs_plus
+
+ DebugChar('|')
+ mov ebx, [kHFSAlBlkSiz]
+ bswap ebx
+ sar ebx, 9
+
+ xor eax, eax
+ mov ax, [kHFSEmbedStart]
+ xchg al, ah ; byte-swap
+ push dx
+ mul ebx ; result in eax
+ pop dx
+
+ xor ebx, ebx
+ mov bx, [kHFSAlBlSt]
+ xchg bl, bh ; byte-swap
+ add eax, ebx
+
+ ;; now eax has sector of HFS+ partition
+ inc eax
+ inc eax
+ mov ecx, eax
+
+ mov al, 1 ; read 1 sector
+ xor bx, bx
+ mov es, bx ; es = 0
+ mov bx, kHFSBuffer ; load volume header
+ call load
+ jc startup_err ; load error
+
+.hfs_plus
+ DebugChar('}')
+ mov ax, [kHFSPlusSigAddr]
+ cmp ax, kHFSPlusSig
+ jne startup_err
+
+;;; Now the HFS+ volume header is in our buffer.
+
+ DebugChar('*')
+ mov eax, [kHFSPlusBlockSize]
+ bswap eax
+ sar eax, 9
+
+ mov ebx, [kHFSPlusExtent]
+ bswap ebx
+ push dx
+ mul ebx ; result in eax
+ pop dx
+
+ dec eax
+ dec eax
+; add [ebios_lba], eax ; offset to startup file
+; mov ecx, [ebios_lba]
+ add ecx, eax
+
+ DebugChar('!')
+
+ mov al, kBoot2Sectors
+ mov bx, kBoot2Segment
+ mov es, bx
+ mov bx, kBoot2Address + kSectorBytes
+ call load
+ jc startup_err
- test bh, bh ; if we are at level 0, then
- jz find_booter_ext_1 ; look for next extended partition entry
+ DebugChar('Y')
+ ;
+ ; Jump to boot2. The drive number is already in register DL.
+ ;
+ jmp kBoot2Segment:kBoot2Address + kSectorBytes
-find_booter_end
- pop si
- pop cx
- ret
+startup_err:
-;--------------------------------------------------------------------------
-; Yeah! Found the booter partition. The first sector in this partition
-; is reserved for the boot sector code (us). So load the booter
-; starting from the second sector in the partition, then jump to the
-; start of the booter.
-;
-load_booter
- mov ax, [si] ; DH/DL
- mov [chs_dx], ax
- mov ax, [si + 2] ; CH/CL
- mov [chs_cx], ax
-
- mov cx, 1 ; skip the initial boot sector
- mov ax, BOOT2_SIZE ; read BOOT2_SIZE sectors
- mov bx, BOOT2_ADDR ; where to place boot2 code
- call load ; load it...
-
- xor edx, edx ; argument for boot2 (hard drive boot)
-%IF BOOTDEV = FLOPPY
- inc edx ; floppy is dev 1
-%ENDIF
- jmp BOOTSEG:BOOT2_ADDR ; there is no going back now!
+ DebugChar('X')
+
+hang:
+ hlt
+ jmp SHORT hang
;--------------------------------------------------------------------------
-; Load sectors from disk using INT13/F2 call. The sectors are loaded
-; one sector at a time to avoid any BIOS bugs, and eliminate
-; complexities with crossing track boundaries, and other gotchas.
+; load - Load one or more sectors from a partition.
;
; Arguments:
-; cx - number of sectors to skip
-; ax - number of sectors to read
-; bx - pointer to the memory buffer (must not cross a segment boundary)
-; [chs_cx][chs_dx] - CHS starting position
+; AL = number of 512-byte sectors to read.
+; ES:BX = pointer to where the sectors should be stored.
+; ECX = sector offset in partition
+; DL = drive number (0x80 + unit number)
+; SI = pointer to the partition entry.
;
; Returns:
; CF = 0 success
-; CF = 1 error
-;
-; The caller must save any registers it needs.
-;
-load
- jcxz load_sectors
- call next_sector ; [chs_cx][chs_dx] <- next sector
- loop load
-
-load_sectors
- mov cx, ax ; cx <- number of sectors to read
-
-load_loop
- call read_sector ; load a single sector
- jc load_exit ; abort if carry flag is set
- add bx, SECTOR_BYTES ; increment buffer pointer
- call next_sector ; [chs_cx][chs_dx] <- next sector
- loop load_loop
- clc ; successful exit
-load_exit
- ret
+; 1 error
+;
+; load:
+; ; push cx
+
+; .ebios:
+; ; mov cx, 5 ; load retry count
+; .ebios_loop:
+; call read_lba ; use INT13/F42
+; jnc .exit
+; ; loop .ebios_loop
+
+; .exit
+; pop cx
+; ret
+
;--------------------------------------------------------------------------
-; Read a single sector from the hard disk.
+; read_lba - Read sectors from a partition using LBA addressing.
;
; Arguments:
-; [chs_cx][chs_dx] - CHS starting position
-; bx - pointer to the sector memory buffer
-; (must not cross a segment boundary)
+; AL = number of 512-byte sectors to read (valid from 1-127).
+; ES:BX = pointer to where the sectors should be stored.
+; ECX = sector offset in partition
+; DL = drive number (0x80 + unit number)
+; SI = pointer to the partition entry.
;
; Returns:
; CF = 0 success
-; CF = 1 error
+; 1 error
;
-; Caller's cx register is preserved.
+read_lba:
+load:
+ pushad ; save all registers
+ mov bp, sp ; save current SP
+
;
-read_sector
- push cx
- mov cx, 5 ; try 5 times to read the sector
+ ; Create the Disk Address Packet structure for the
+ ; INT13/F42 (Extended Read Sectors) on the stack.
+ ;
-read_sector_1
- mov bp, cx ; save cx
+ ; push DWORD 0 ; offset 12, upper 32-bit LBA
+ push ds ; For sake of saving memory,
+ push ds ; push DS register, which is 0.
- mov cx, [chs_cx]
- mov dx, [chs_dx]
- mov dl, DRIVE_NUM ; drive number
- mov ax, 0x0201 ; Func 2, read 1 sector
- int 0x13 ; read sector
- jnc read_sector_ok ; CF = 0 indicates success
+ add ecx, [ebios_lba] ; offset 8, lower 32-bit LBA
+ add ecx, [si + part.lba]
- mov al, '*' ; sector read error indicator
- call putchar
+ push ecx
- xor ax, ax ; Reset the drive and retry the read
- int 0x13
+ push es ; offset 6, memory segment
- mov cx, bp
- loop read_sector_1 ; retry while cx is not zero
+ push bx ; offset 4, memory offset
- stc ; set carry flag to indicate error
- pop cx
- ret
+ xor ah, ah ; offset 3, must be 0
+ push ax ; offset 2, number of sectors
-read_sector_ok
- mov al, '.' ; successful sector read indicator
- call putchar
- clc ; success, clear carry flag
- pop cx
- ret
+%if DEBUG
+ push ax
+ DebugChar('-') ; absolute sector offset
+ mov eax, ecx
+ call print_hex
+ DebugChar('=') ; count
+ pop ax
+ call print_hex
+%endif
+
+ push WORD 16 ; offset 0-1, packet size
-;--------------------------------------------------------------------------
-; Given the current CHS position stored in [chs_cx][chs_dx], update
-; it so that the value in [chs_cx][chs_dx] points to the following
-; sector.
;
-; Arguments:
-; [chs_cx][chs_dx] - CHS position
+ ; INT13 Func 42 - Extended Read Sectors
;
-; [max_sectors] and [max_heads] must be valid.
+ ; Arguments:
+ ; AH = 0x42
+ ; DL = drive number (80h + drive unit)
+ ; DS:SI = pointer to Disk Address Packet
;
-; Caller's ax and bx registers are preserved.
+ ; Returns:
+ ; AH = return status (sucess is 0)
+ ; carry = 0 success
+ ; 1 error
;
-next_sector
- push ax
- push bx
-
- ; Extract the CHS values from the packed register values in memory.
+ ; Packet offset 2 indicates the number of sectors read
+ ; successfully.
;
- mov al, [chs_cx]
- and al, 0x3f ; al <- sector number (1-63)
-
- mov bx, [chs_cx]
- rol bl, 2
- ror bx, 8
- and bx, 0x03ff ; bx <- cylinder number
-
- mov ah, [chs_dx + 1] ; ah <- head number
-
- inc al ; Increment CHS by one sector.
- cmp al, [max_sectors]
- jbe next_sector_done
-
- inc ah
- cmp ah, [max_heads]
- jbe next_sector_new_head
-
- inc bx
+; mov dl, kDriveNumber
+ mov si, sp
+ mov ah, 0x42
+ int 0x13
-next_sector_new_cyl
- xor ah, ah ; head number starts at 0
+ jnc .exit
-next_sector_new_head
- mov al, 1 ; sector number starts at 1
+%if DEBUG
+ call print_hex
+%endif
+ DebugChar('R') ; indicate INT13/F42 error
-next_sector_done
- ; Reassemble the CHS values back into the packed representation
- ; in memory.
;
- mov [chs_cx + 1], bl ; lower 8-bits of the 10-bit cylinder
- ror bh, 2
- or bh, al
- mov [chs_cx], bh ; cylinder & sector number
- mov [chs_dx + 1], ah ; head number
+ ; Issue a disk reset on error.
+ ; Should this be changed to Func 0xD to skip the diskette controller
+ ; reset?
+ ;
+ xor ax, ax ; Func 0
+ int 0x13 ; INT 13
+ stc ; set carry to indicate error
- pop bx
- pop ax
+.exit:
+ mov sp, bp ; restore SP
+ popad
ret
-;--------------------------------------------------------------------------
+%if 0
+;-------------------------------------------------------------------------
; Write a string to the console.
;
; Arguments:
-; ds:si pointer to a NULL terminated string.
+; DS:SI pointer to a NULL terminated string.
;
-; The following registers are modified:
-; ax, bx, si
+; Clobber list:
+; AX, BX, SI
;
-message
- mov bx, 1 ; bh=0, bl=1 (blue)
+print_string
+ mov bx, 1 ; BH=0, BL=1 (blue)
cld ; increment SI after each lodsb call
-message_loop
- lodsb ; load a byte from DS:SI into al
+.loop
+ lodsb ; load a byte from DS:SI into AL
cmp al, 0 ; Is it a NULL?
- je message_done ; yes, all done
- mov ah, 0xE ; bios INT10 Func 0xE
- int 0x10 ; bios display a byte in tty mode
- jmp short message_loop
-message_done
+ je .exit ; yes, all done
+ mov ah, 0xE ; INT10 Func 0xE
+ int 0x10 ; display byte in tty mode
+ jmp short .loop
+.exit
ret
+%endif
+
+%if DEBUG
;--------------------------------------------------------------------------
; Write a ASCII character to the console.
;
; Arguments:
-; al contains the ASCII character printed.
-;
-putchar
- push bx
- mov bx, 1 ; bh=0, bl=1 (blue)
- mov ah, 0x0e ; bios int 10, function 0xe
- int 0x10 ; bios display a byte in tty mode
- pop bx
+; AL = ASCII character.
+;
+print_char
+ pushad
+ mov bx, 1 ; BH=0, BL=1 (blue)
+ mov ah, 0x0e ; bios INT 10, Function 0xE
+ int 0x10 ; display byte in tty mode
+ popad
ret
-%IF DEBUG
-;==========================================================================
-; DEBUG FUNCTION START
-;
-; If DEBUG is set to 1, this booter will become too large for the MBR,
-; but it will still be less than 510 bytes, which is fine for a partition's
-; boot sector.
-;==========================================================================
-
;--------------------------------------------------------------------------
; Write a variable number of spaces to the console.
;
; Arguments:
-; al number to spaces to display
+; AL = number to spaces.
;
-putspace
- push cx
+print_spaces:
+ pushad
xor cx, cx
- mov cl, al ; use cx as the loop counter
+ mov cl, al ; use CX as the loop counter
mov al, ' ' ; character to print
-putspace_loop
- jcxz putspace_done
- call putchar
- loop putspace_loop
-putspace_done
- pop cx
+.loop:
+ jcxz .exit
+ call print_char
+ loop .loop
+.exit:
+ popad
ret
;--------------------------------------------------------------------------
-; Write the hex byte value to the console.
+; Write the byte value to the console in hex.
;
; Arguments:
-; al contains the byte to be displayed. e.g. if al is 0x3f, then 3F
-; will be displayed on screen.
+; AL = Value to be displayed in hex.
;
-display_byte
+print_hex:
+ pushad
+ mov cx, WORD 4
+ bswap eax
+.loop
push ax
ror al, 4
- call display_nibble ; display upper nibble
+ call print_nibble ; display upper nibble
pop ax
- call display_nibble ; display lower nibble
- ;
- mov ax, 10 ; display carriage return
- call putchar
- mov ax, 13
- call putchar
+ call print_nibble ; display lower nibble
+ ror eax, 8
+ loop .loop
+
+ mov al, 10 ; carriage return
+ call print_char
+ mov al, 13
+ call print_char
+ popad
ret
-display_nibble
+print_nibble:
and al, 0x0f
add al, '0'
cmp al, '9'
- jna display_nibble_1
+ jna .print_ascii
add al, 'A' - '9' - 1
-display_nibble_1
- call putchar
+.print_ascii:
+ call print_char
ret
-;==========================================================================
-; DEBUG FUNCTION END
-;==========================================================================
-%ENDIF
-
-; Disk parameters gathered through INT13/F8 call.
-;
-max_sectors db 0 ; number of sectors per track
-max_heads db 0 ; number of heads
+getc:
+ mov ah, 0
+ int 0x16
+ ret
-; Parameters to our load function.
-;
-chs_cx dw 0x0001 ; cx register for INT13/F2 call
-chs_dx dw 0x0000 ; dx register for INT13/F2 call
+%endif ; DEBUG
;--------------------------------------------------------------------------
; NULL terminated strings.
;
-load_error db 10, 13, 'Load Error', 0
+; boot_error_str db 10, 13, 'Error', 0
;--------------------------------------------------------------------------
; Pad the rest of the 512 byte sized booter with zeroes. The last
; that the 'times' argument is negative.
pad_boot
- times 446-($-$$) db 0
+ times 510-($-$$) db 0
-%IF BOOTDEV = FLOPPY
+%ifdef FLOPPY
;--------------------------------------------------------------------------
; Put fake partition entries for the bootable floppy image
;
-part1bootid db 0x80 ; first partition active
-part1head db 0x00 ; head #
-part1sect db 0x02 ; sector # (low 6 bits)
-part1cyl db 0x00 ; cylinder # (+ high 2 bits of above)
-part1systid db 0xab ; Apple boot partition
-times 3 db 0x00 ; ignore head/cyl/sect #'s
-part1relsect dd 0x00000001 ; start at sector 1
-part1numsect dd 0x00000058 ; 44K for booter
-part2bootid db 0x00 ; not active
-times 3 db 0x00 ; ignore head/cyl/sect #'s
-part2systid db 0xa8 ; Apple UFS partition
-times 3 db 0x00 ; ignore head/cyl/sect #'s
-part2relsect dd 0x0000005a ; start after booter
-; part2numsect dd 0x00000ae6 ; 1.44MB - 45K
-part2numsect dd 0x00001626 ; 2.88MB - 45K
-%ENDIF
+part1bootid db 0x80 ; first partition active
+part1head db 0x00 ; head #
+part1sect db 0x02 ; sector # (low 6 bits)
+part1cyl db 0x00 ; cylinder # (+ high 2 bits of above)
+part1systid db 0xab ; Apple boot partition
+times 3 db 0x00 ; ignore head/cyl/sect #'s
+part1relsect dd 0x00000001 ; start at sector 1
+part1numsect dd 0x00000080 ; 64K for booter
+part2bootid db 0x00 ; not active
+times 3 db 0x00 ; ignore head/cyl/sect #'s
+part2systid db 0xa8 ; Apple UFS partition
+times 3 db 0x00 ; ignore head/cyl/sect #'s
+part2relsect dd 0x00000082 ; start after booter
+; part2numsect dd 0x00000abe ; 1.44MB - 65K
+part2numsect dd 0x000015fe ; 2.88MB - 65K
+%endif
pad_table_and_sig
times 510-($-$$) db 0
- dw BOOTSIG
+ dw kBootSignature
END
projects / apple / boot.git / blobdiff