mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-09-21 02:51:04 +02:00
598 lines
14 KiB
ArmAsm
598 lines
14 KiB
ArmAsm
; Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
|
|
;
|
|
; @APPLE_LICENSE_HEADER_START@
|
|
;
|
|
; Portions Copyright (c) 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.apple.com/publicsource 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
|
|
; 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.
|
|
;
|
|
; @APPLE_LICENSE_HEADER_END@
|
|
; nasm cdboot.s -o cdboot
|
|
;
|
|
; This version of cdboot loads 256k of data.
|
|
;
|
|
; Modifications by Tamás Kosárszky on 2008-10-20
|
|
;
|
|
|
|
;
|
|
; Set to 1 to enable obscure debug messages.
|
|
;
|
|
DEBUG EQU 0
|
|
|
|
;
|
|
; Set to 1 to enable unused code.
|
|
;
|
|
UNUSED EQU 0
|
|
|
|
;
|
|
; Set to 1 to enable verbose mode.
|
|
;
|
|
VERBOSE EQU 1
|
|
|
|
;
|
|
; Various constants.
|
|
;
|
|
NULL EQU 0
|
|
CR EQU 0x0D
|
|
LF EQU 0x0A
|
|
|
|
;
|
|
; Macros.
|
|
;
|
|
%macro jmpabs 1
|
|
push WORD %1
|
|
ret
|
|
%endmacro
|
|
|
|
%macro DebugCharMacro 1
|
|
pushad
|
|
mov al, %1
|
|
call print_char
|
|
call getc
|
|
popad
|
|
%endmacro
|
|
|
|
%macro DebugPauseMacro 0
|
|
push ax
|
|
call getc
|
|
pop ax
|
|
%endmacro
|
|
|
|
%macro PrintCharMacro 1
|
|
pushad
|
|
mov al, %1
|
|
call print_char
|
|
popad
|
|
%endmacro
|
|
|
|
%macro PutCharMacro 1
|
|
call print_char
|
|
%endmacro
|
|
|
|
%macro PrintHexMacro 1
|
|
; call print_hex
|
|
%endmacro
|
|
|
|
%macro PrintString 1
|
|
mov si, %1
|
|
call print_string
|
|
%endmacro
|
|
|
|
%macro LogString 1
|
|
mov di, %1
|
|
call log_string
|
|
%endmacro
|
|
|
|
%if DEBUG
|
|
%define DebugChar(x) DebugCharMacro x
|
|
%define DebugPause(x) DebugPauseMacro
|
|
%define PrintChar(x) PrintCharMacro x
|
|
%define PutChar(x) PutCharMacro
|
|
%define PrintHex(x) ;PrintHexMacro x
|
|
%else
|
|
%define DebugChar(x)
|
|
%define DebugPause(x)
|
|
%define PrintChar(x)
|
|
%define PutChar(x)
|
|
%define PrintHex(x)
|
|
%endif
|
|
|
|
maxSectorCount EQU 8 ; maximum sector count for readSectors
|
|
CDBootSizeMagic EQU 0xDEADFACE ; indicates if the size field was not specificed
|
|
; at build time.
|
|
kSectorBytes EQU 2048 ; sector size in bytes
|
|
kBoot2Size EQU 65024 ; default load size for boot2
|
|
kBoot2MaxSize EQU (472*1024-512) ;458240 ; max size for boot2
|
|
kBoot2Address EQU 0x0200 ; boot2 load address
|
|
kBoot2Segment EQU 0x2000 ; boot2 load segment
|
|
|
|
kBoot0Stack EQU 0xFFF0 ; boot0 stack pointer
|
|
|
|
kReadBuffer EQU 0x1000 ; disk data buffer address
|
|
|
|
kVolSectorOffset EQU 0x47 ; offset in buffer of sector number
|
|
; in volume descriptor
|
|
kBootSectorOffset EQU 0x28 ; offset in boot catalog
|
|
; of sector number to load boot file
|
|
kBootCountOffset EQU 0x26 ; offset in boot catalog
|
|
; of number of sectors to read
|
|
kCDBootSizeOffset EQU 2048 - 4 ; the file size can be found at the
|
|
; last dword of this sector.
|
|
|
|
;--------------------------------------------------------------------------
|
|
; Start of text segment.
|
|
|
|
SEGMENT .text
|
|
|
|
ORG 0x7C00
|
|
|
|
;--------------------------------------------------------------------------
|
|
; Boot code is loaded at 0:7C00h.
|
|
;
|
|
|
|
start:
|
|
cli
|
|
jmp 0:start1
|
|
times 8-($-$$) nop ; Put boot information table at offset 8
|
|
|
|
; El Torito boot information table, filled in by the
|
|
; mkisofs -boot-info-table option, if used.
|
|
bi_pvd: dd 0 ; LBA of primary volume descriptor
|
|
bi_file: dd 0 ; LBA of boot file
|
|
bi_length: dd 0 ; Length of boot file
|
|
bi_csum: dd 0 ; Checksum of boot file
|
|
bi_reserved: times 10 dd 0 ; Reserved
|
|
|
|
start1:
|
|
xor ax, ax ; zero %ax
|
|
mov ss, ax ; setup the
|
|
mov sp, kBoot0Stack ; stack
|
|
sti
|
|
cld ; increment SI after each lodsb call
|
|
mov ds, ax ; setup the
|
|
mov es, ax ; data segments
|
|
|
|
%if VERBOSE
|
|
LogString(init_str)
|
|
%endif
|
|
|
|
;; BIOS boot drive is in DL
|
|
mov [gBIOSDriveNumber], dl ; save BIOS drive number
|
|
|
|
DebugChar('!')
|
|
DebugPause()
|
|
|
|
%if 0 ;DEBUG
|
|
mov eax, [kBoot2LoadAddr]
|
|
call print_hex
|
|
call getc
|
|
%endif
|
|
|
|
;;
|
|
;; The BIOS likely didn't load the rest of the booter,
|
|
;; so we have to fetch it ourselves.
|
|
;;
|
|
mov edx, kReadBuffer
|
|
mov al, 1
|
|
mov ecx, 17
|
|
call readLBA
|
|
jc NEAR error
|
|
|
|
DebugChar('A')
|
|
|
|
mov ecx, [kReadBuffer + kVolSectorOffset]
|
|
|
|
%if 0 ;DEBUG
|
|
mov eax, ecx
|
|
call print_hex
|
|
DebugPause()
|
|
%endif
|
|
|
|
mov al, 1
|
|
call readLBA
|
|
jc NEAR error
|
|
|
|
;; Now we have the boot catalog in the buffer.
|
|
;; Really we should look at the validation entry, but oh well.
|
|
|
|
DebugChar('B')
|
|
|
|
mov ecx, [kReadBuffer + kBootSectorOffset]
|
|
mov al, 1
|
|
call readLBA ; reading this boot sector
|
|
|
|
inc ecx ; skip the first sector which is what we are in
|
|
|
|
%if 0 ;DEBUG
|
|
mov eax, ecx
|
|
call print_hex
|
|
DebugPause()
|
|
%endif
|
|
|
|
;
|
|
; Testing cdboot size
|
|
;
|
|
|
|
mov eax, [kReadBuffer + kCDBootSizeOffset]
|
|
or eax, eax
|
|
jz .useDefaultSize ; use the default size if zero
|
|
cmp eax, CDBootSizeMagic
|
|
je .useDefaultSize ; use the default size if equals to magic
|
|
cmp eax, kBoot2MaxSize
|
|
jbe .calcSectors ; use the actual size
|
|
|
|
.useDefaultSize:
|
|
|
|
mov eax, kBoot2Size
|
|
|
|
%if VERBOSE
|
|
LogString(defaultsize_str)
|
|
%endif
|
|
|
|
.calcSectors:
|
|
|
|
%if VERBOSE
|
|
LogString(size_str)
|
|
; call print_hex
|
|
%endif
|
|
|
|
add eax, kSectorBytes - 1 ; adjust size before unit conversion
|
|
shr eax, 11 ; convert file size to CD sector unit
|
|
|
|
%if VERBOSE
|
|
LogString(read_str)
|
|
; call print_hex
|
|
%endif
|
|
|
|
%if VERBOSE
|
|
LogString(loading_str)
|
|
%endif
|
|
|
|
mov edx, (kBoot2Segment << 4) + kBoot2Address
|
|
call readSectors
|
|
jc error
|
|
|
|
DebugChar('C')
|
|
|
|
%if 0 ;DEBUG
|
|
mov eax, [es:kBoot2Address]
|
|
call print_hex
|
|
DebugPause()
|
|
%endif
|
|
|
|
DebugChar('X')
|
|
DebugPause()
|
|
|
|
;; Jump to newly-loaded booter
|
|
|
|
%if VERBOSE
|
|
LogString(done_str)
|
|
%endif
|
|
|
|
%if UNUSED
|
|
LogString(keypress_str)
|
|
call getc
|
|
%endif
|
|
|
|
mov dl, [gBIOSDriveNumber] ; load BIOS drive number
|
|
jmp kBoot2Segment:kBoot2Address
|
|
|
|
error:
|
|
|
|
%if VERBOSE
|
|
LogString(error_str)
|
|
%endif
|
|
|
|
.loop:
|
|
hlt
|
|
jmp .loop
|
|
|
|
;;
|
|
;; Support functions
|
|
;;
|
|
|
|
;--------------------------------------------------------------------------
|
|
; readSectors - Reads more than 127 sectors using LBA addressing.
|
|
;
|
|
; Arguments:
|
|
; AX = number of 2048-byte sectors to read (valid from 1-320).
|
|
; EDX = pointer to where the sectors should be stored.
|
|
; ECX = sector offset in partition
|
|
;
|
|
; Returns:
|
|
; CF = 0 success
|
|
; 1 error
|
|
;
|
|
readSectors:
|
|
pushad
|
|
mov bx, ax
|
|
|
|
.loop:
|
|
mov al, '.'
|
|
call print_char
|
|
xor eax, eax ; EAX = 0
|
|
mov al, bl ; assume we reached the last block.
|
|
cmp bx, maxSectorCount ; check if we really reached the last block
|
|
jb .readBlock ; yes, BX < MaxSectorCount
|
|
mov al, maxSectorCount ; no, read MaxSectorCount
|
|
|
|
.readBlock:
|
|
call readLBA
|
|
jc .exit
|
|
sub bx, ax ; decrease remaning sectors with the read amount
|
|
jz .exit ; exit if no more sectors left to be loaded
|
|
add ecx, eax ; adjust LBA sector offset
|
|
shl eax, 11 ; convert CD sectors to bytes
|
|
add edx, eax ; adjust target memory location
|
|
jmp .loop ; read remaining sectors
|
|
|
|
.exit:
|
|
popad
|
|
ret
|
|
|
|
;--------------------------------------------------------------------------
|
|
; readLBA - Read sectors from a partition using LBA addressing.
|
|
;
|
|
; Arguments:
|
|
; AL = number of 512-byte sectors to read (valid from 1-127).
|
|
; EDX = pointer to where the sectors should be stored.
|
|
; ECX = sector offset in partition
|
|
; [gBIOSDriveNumber] = drive number (0x80 + unit number)
|
|
;
|
|
; Returns:
|
|
; CF = 0 success
|
|
; 1 error
|
|
;
|
|
readLBA:
|
|
pushad ; save all registers
|
|
push es ; save ES
|
|
mov bp, sp ; save current SP
|
|
|
|
;
|
|
; Convert EDX to segment:offset model and set ES:BX
|
|
;
|
|
; Some BIOSes do not like offset to be negative while reading
|
|
; from hard drives. This usually leads to "boot1: error" when trying
|
|
; to boot from hard drive, while booting normally from USB flash.
|
|
; The routines, responsible for this are apparently different.
|
|
; Thus we split linear address slightly differently for these
|
|
; capricious BIOSes to make sure offset is always positive.
|
|
;
|
|
|
|
mov bx, dx ; save offset to BX
|
|
and bh, 0x0f ; keep low 12 bits
|
|
shr edx, 4 ; adjust linear address to segment base
|
|
xor dl, dl ; mask low 8 bits
|
|
mov es, dx ; save segment to ES
|
|
|
|
;
|
|
; Create the Disk Address Packet structure for the
|
|
; INT13/F42 (Extended Read Sectors) on the stack.
|
|
;
|
|
|
|
; push DWORD 0 ; offset 12, upper 32-bit LBA
|
|
push ds ; For sake of saving memory,
|
|
push ds ; push DS register, which is 0.
|
|
|
|
push ecx
|
|
|
|
push es ; offset 6, memory segment
|
|
|
|
push bx ; offset 4, memory offset
|
|
|
|
xor ah, ah ; offset 3, must be 0
|
|
push ax ; offset 2, number of sectors
|
|
|
|
push WORD 16 ; offset 0-1, packet size
|
|
|
|
;
|
|
; INT13 Func 42 - Extended Read Sectors
|
|
;
|
|
; Arguments:
|
|
; AH = 0x42
|
|
; [gBIOSDriveNumber] = drive number (0x80 + unit number)
|
|
; DS:SI = pointer to Disk Address Packet
|
|
;
|
|
; Returns:
|
|
; AH = return status (sucess is 0)
|
|
; carry = 0 success
|
|
; 1 error
|
|
;
|
|
; Packet offset 2 indicates the number of sectors read
|
|
; successfully.
|
|
;
|
|
mov dl, [gBIOSDriveNumber] ; load BIOS drive number
|
|
mov si, sp
|
|
mov ah, 0x42
|
|
int 0x13
|
|
|
|
jnc .exit
|
|
|
|
DebugChar('R') ; indicate INT13/F42 error
|
|
|
|
;
|
|
; Issue a disk reset on error.
|
|
; Should this be changed to Func 0xD to skip the diskette controller
|
|
; reset?
|
|
;
|
|
|
|
%if VERBOSE
|
|
LogString(readerror_str)
|
|
mov eax, ecx
|
|
; call print_hex
|
|
%endif
|
|
|
|
xor ax, ax ; Func 0
|
|
int 0x13 ; INT 13
|
|
stc ; set carry to indicate error
|
|
|
|
.exit:
|
|
mov sp, bp ; restore SP
|
|
pop es ; restore ES
|
|
popad
|
|
ret
|
|
|
|
;--------------------------------------------------------------------------
|
|
; Write a string with 'cdboot: ' prefix to the console.
|
|
;
|
|
; Arguments:
|
|
; ES:DI pointer to a NULL terminated string.
|
|
;
|
|
; Clobber list:
|
|
; DI
|
|
;
|
|
log_string:
|
|
pushad
|
|
|
|
push di
|
|
mov si, log_title_str
|
|
call print_string
|
|
|
|
pop si
|
|
call print_string
|
|
|
|
popad
|
|
|
|
ret
|
|
|
|
;-------------------------------------------------------------------------
|
|
; Write a string to the console.
|
|
;
|
|
; Arguments:
|
|
; DS:SI pointer to a NULL terminated string.
|
|
;
|
|
; Clobber list:
|
|
; AX, BX, SI
|
|
;
|
|
print_string:
|
|
mov bx, 1 ; BH=0, BL=1 (blue)
|
|
|
|
.loop:
|
|
lodsb ; load a byte from DS:SI into AL
|
|
cmp al, 0 ; Is it a NULL?
|
|
je .exit ; yes, all done
|
|
mov ah, 0xE ; INT10 Func 0xE
|
|
int 0x10 ; display byte in tty mode
|
|
jmp .loop
|
|
|
|
.exit:
|
|
ret
|
|
|
|
;%if DEBUG
|
|
|
|
;--------------------------------------------------------------------------
|
|
; Write the 4-byte value to the console in hex.
|
|
;
|
|
; Arguments:
|
|
; EAX = Value to be displayed in hex.
|
|
;
|
|
%if 0
|
|
print_hex:
|
|
pushad
|
|
mov cx, WORD 4
|
|
bswap eax
|
|
.loop:
|
|
push ax
|
|
ror al, 4
|
|
call print_nibble ; display upper nibble
|
|
pop ax
|
|
call print_nibble ; display lower nibble
|
|
ror eax, 8
|
|
loop .loop
|
|
|
|
%if UNUSED
|
|
mov al, 10 ; carriage return
|
|
call print_char
|
|
mov al, 13
|
|
call print_char
|
|
%endif ; UNUSED
|
|
|
|
popad
|
|
ret
|
|
|
|
print_nibble:
|
|
and al, 0x0f
|
|
add al, '0'
|
|
cmp al, '9'
|
|
jna .print_ascii
|
|
add al, 'A' - '9' - 1
|
|
.print_ascii:
|
|
call print_char
|
|
ret
|
|
%endif
|
|
;--------------------------------------------------------------------------
|
|
; getc - wait for a key press
|
|
;
|
|
getc:
|
|
pushad
|
|
mov ah, 0
|
|
int 0x16
|
|
popad
|
|
ret
|
|
|
|
;--------------------------------------------------------------------------
|
|
; Write a ASCII character to the console.
|
|
;
|
|
; Arguments:
|
|
; 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
|
|
|
|
;--------------------------------------------------------------------------
|
|
; Static data.
|
|
;
|
|
|
|
%if VERBOSE
|
|
log_title_str db CR, LF, 'cdboot: ', NULL
|
|
init_str db 'init', NULL
|
|
defaultsize_str db 'using default size', NULL
|
|
size_str db 'file size: ', NULL
|
|
read_str db 'reading sectors: ', NULL
|
|
loading_str db 'loading', NULL
|
|
done_str db 'done', NULL
|
|
readerror_str db 'BIOS error at: ', NULL
|
|
error_str db 'error', NULL
|
|
%endif
|
|
|
|
%if UNUSED
|
|
keypress_str db 'Press any key to continue...', NULL
|
|
%endif
|
|
|
|
|
|
;; Pad this file to a size of 2048 bytes (one CD sector).
|
|
pad:
|
|
times 2044-($-$$) db 0
|
|
|
|
CDBootSize dd CDBootSizeMagic
|
|
|
|
;; Location of loaded boot2 code.
|
|
kBoot2LoadAddr equ $
|
|
|
|
;
|
|
; Global variables
|
|
;
|
|
|
|
ABSOLUTE kReadBuffer + kSectorBytes
|
|
|
|
gBIOSDriveNumber resw 1
|
|
|
|
; END
|