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Fixed the usb ipl for 31_day
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@jeffreyc2017
jeffreyc2017 committed Jul 20, 2024
1 parent 810fd4d commit b43e3fa
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5 changes: 5 additions & 0 deletions docs/references.md
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# References

- https://wiki.osdev.org/Expanded_Main_Page
- [Original book website](http://hrb.osask.jp)
- http://oswiki.osask.jp/
- [Intel 386 and AMD x86-64 Options](https://gcc.gnu.org/onlinedocs/gcc-4.7.2/gcc/i386-and-x86_002d64-Options.html)
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- https://viterbi-web.usc.edu/~yudewei/main/sources/books/30天自制操作系统/
- https://www.linux.com

- https://en.wikipedia.org/wiki/INT_13H#INT_13h_AH=43h:_Extended_Write_Sectors_to_Drive
- https://www.cs.cmu.edu/~ralf/files.html
- https://web.archive.org/web/20160619044934/http://www.ctyme.com/intr/int-13.htm
120 changes: 35 additions & 85 deletions projects/31_day/harib28a/haribote/ipl09usb.nas
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; haribote-ipl
; TAB=4

CYLS EQU 20 ; Number of cylinders (not used in this code but defined for reference)
CYLS EQU 15 ; How far to read
DRVNO EQU 0x80 ; Drive number (0x80: first HDD)

ORG 0x7c00 ; Origin of the code. The BIOS loads the bootloader at address 0x7c00

; BPB Structure (BIOS Parameter Block) for FAT32

JMP SHORT entry ; Jump to the entry point of the bootloader code
NOP ; No operation, used for alignment
NOP ; No operation, used for alignment

BS_OEMName DB "HARIBOTE" ; [8 bytes] OEM name or identifier
BPB_BytsPerSec DW 0x0200 ; Bytes per sector (512 bytes). Standard for FAT12/16/32
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; Read disk and initialize the system

MOV DL, 0x80 ; Set DL to 0x80 to specify the first hard disk drive
MOV [drv], DL ; Store the drive number (DL) into memory (for later use)

; Check if extended INT 0x13 is available

MOV AH, 0x41 ; BIOS interrupt 0x13, function 0x41: check if extended INT 13h is available
MOV BX, 0x55aa ; Fixed value to check for extended INT 13h support
INT 0x13 ; Call BIOS interrupt 0x13
JC nosupport ; Jump to nosupport label if carry flag is set (indicates failure)

XOR AX, AX ; Clear AX register (AX = 0)
ADD AX, 1 ; Add 1 to AX (used to clear carry flag)
XOR EDI, EDI ; Clear EDI register (EDI = 0)
MOV DI, [DAPS.lba]

; Perform disk operations using the drive number in DL

MOV AH, 0x45 ; BIOS interrupt 0x13, function 0x45: lock the drive
MOV AL, 0x01 ; Lock drive 0x80
MOV DL, 0x80 ; Drive number 0x80 (first HDD)
MOV DL, DRVNO ; Drive number 0x80 (first HDD)
INT 0x13 ; Call BIOS interrupt 0x13 to lock the drive

MOV AX, 0 ; Clear AX register
MOV DS, AX ; Set Data Segment (DS) to 0 (base address)

loop:
MOV CL, 0 ; Clear CL register (used for retry counter)
retry:
PUSH DS ; Save Data Segment (DS) on stack
PUSHAD ; Save all general-purpose registers on stack
MOV DL, [drv] ; Load drive number from memory
MOV DL, DRVNO ; Load drive number from memory
MOV AH, 0x42 ; BIOS interrupt 0x13, function 0x42: extended read disk
MOV AL, 0x00 ; Read 1 sector (specified by count)
MOV SI, DAPS ; Load address of Disk Address Packet (DAPS)
INT 0x13 ; Call BIOS interrupt 0x13 to read the disk
JNC next ; Jump to next if no carry (indicates success)

ADD CL, 1 ; Increment retry counter
MOV DL, 0x80 ; Reset drive
MOV DL, DRVNO ; Reset drive
MOV AH, 0x00 ; BIOS interrupt 0x13, function 0x00: reset drive
INT 0x13 ; Call BIOS interrupt 0x13
CMP CL, 6 ; Compare retry counter with 6
JGE error ; Jump to error if retry counter >= 6
JMP retry ; Jump back to retry reading disk

next:
XOR EAX, EAX ; Clear EAX register
XOR EBX, EBX ; Clear EBX register
XOR ECX, ECX ; Clear ECX register
ADD DI, 1 ; Increment DI (used to track sectors read)
MOV [DAPS.lba], DI ; Store incremented DI to LBA address

ADD EDI, 1 ; Increment EDI (used to track sectors read)
MOV ECX, lba0 ; Load address of LBA (Logical Block Address) 0
MOV [ECX], EDI ; Store incremented EDI to LBA address

XOR EAX, EAX ; Clear EAX register
XOR ECX, ECX ; Clear ECX register
XOR EBP, EBP ; Clear EBP register

MOV AX, [addr] ; Load address from memory (target location for reading)
MOV ECX, addr ; Load address of addr
MOV EBX, segm ; Load address of segment
MOV AX, [DAPS.addr] ; Load address from memory (target location for reading)
ADD AX, 0x200 ; Add 0x200 to AX (offset adjustment)
MOV [DAPS.addr], AX ; Store address in DAPS.addr
ADC BP, 0 ; Add carry to BP (for address calculation)
SHL BP, 12 ; Shift BP left by 12 (address scaling)
ADD BP, [segm] ; Add segment base address to BP
MOV [EBX], BP ; Store computed address in EBX

MOV [ECX], AX ; Store address in ECX
MOV [EBX], BP ; Store base address in EBX
ADD BP, [DAPS.segm] ; Add segment base address to BP
MOV [DAPS.segm], BP ; Store computed address in DAPS.segm

CMP EDI, 0x16a ; Compare EDI with 0x16a (check if all sectors read)
JL loop ; Jump to loop if EDI < 0x16a
CMP DI, 0x21c ; check if all sectors read
JL loop ;

MOV ECX, 0xc200 ; Load address to jump to (0xc200 in segment 0x0000)

MOV EAX, 0x0000 ; Clear EAX register
MOV EBX, EAX ; Clear EBX register
MOV EDX, EAX ; Clear EDX register
MOV EBP, EAX ; Clear EBP register
MOV ES, AX ; Set Extra Segment (ES) to 0
MOV ESI, EAX ; Clear ESI register
MOV EDI, EAX ; Clear EDI register

MOV CH, 10 ; Load 0x0A (newline character) into CH
MOV [0x0ff0], CH ; Store CH at 0x0ff0 (for display purposes)

MOV ECX, EAX ; Clear ECX register
JMP 0x0000:0xc200 ; Jump to address 0xc200 in segment 0x0000
MOV BYTE [0x0ff0], CYLS ; Note how far the IPL has read
JMP 0xc200 ; Jump to address 0xc200 in segment 0x0000

nosupport:
MOV SI, msg_nos ; Load address of "extINT13H not supported" message
JMP putloop ; Jump to putloop to display the message

error:
POPAD ; Restore all general-purpose registers from stack
POP DS ; Restore Data Segment (DS) from stack
MOV SI, msg ; Load address of "load error" message
JMP putloop ; Jump to putloop to display the message

putloop:
MOV AL, [SI] ; Load character from message into AL
ADD SI, 1 ; Increment message pointer (SI)
CMP AL, 0 ; Compare AL with 0 (end of message)
JE fin ; Jump to fin if end of message
MOV AH, 0x0e ; BIOS interrupt 0x10, function 0x0e: teletype output
MOV BX, [chclr] ; Load color code for output
MOV BX, 15 ; Load color code for output
INT 0x10 ; Call BIOS interrupt 0x10 to output character
JMP putloop ; Jump back to putloop to display next character

error:
MOV SI, msg ; Load address of "load error" message
JMP putloop ; Jump to putloop to display the message

fin:
HLT ; Halt the CPU (end of bootloader execution)
JMP fin ; Infinite loop to prevent further execution

msg:
DB "load error" ; Error message to display
DB 0x0d, 0x0a ; CR LF (Carriage Return and Line Feed)
DB 0 ; Null terminator for the string
DB 0x0d, 0x0a ; CR LF (Carriage Return and Line Feed)
DB 0 ; Null terminator for the string

msg_nos:
DB 0x0d, 0x0a ; CR LF (Carriage Return and Line Feed)
DB 0x0d, 0x0a ; CR LF (Carriage Return and Line Feed)
DB "extINT13H not supported" ; Message indicating extended INT 13h not supported
DB 0x0d, 0x0a ; CR LF (Carriage Return and Line Feed)
DB 0 ; Null terminator for the string

drv:
DB 0x80 ; Drive number (0x80: first HDD)

chclr:
DW 0x000f ; Color code for text output (15 = light grey on black)
DB 0x0d, 0x0a ; CR LF (Carriage Return and Line Feed)
DB 0 ; Null terminator for the string

align 4
DAPS:
DB 0x10 ; Size of Disk Address Packet (16 bytes)
DB 0 ; Reserved, always 0
count:
DB 539 ; Number of sectors to read (1 sector = 512 bytes)
DB 0 ; Reserved, always 0
addr:
DW 0x8000 ; Target location for reading data (0x8000)
segm:
DW 0x0000 ; Segment address (0x0000)
lba0:
DD 1 ; Read from LBA 1 (second block)
.packet_size DB 0x10 ; Size of Disk Address Packet (16 bytes)
.reserved DB 0 ; Reserved, always 0
.block_count DW 1 ; Number of blocks to transfer (1 sector = 512 bytes)
.addr DW 0x8000 ; Target location for reading data to (0x8000)
.segm DW 0x0000 ; Segment address (0x0000)
.lba DQ 0 ; Read from LBA 1 (second block)

TIMES 0x7dfe-0x7c00-($-$$) DB 0 ; Fill the remainder of the boot sector with zeros
DB 0x55, 0xaa ; Boot signature (0x55AA), required for BIOS to recognize bootable disk
DB 0x55, 0xaa ; Boot signature (0x55AA), required for BIOS to recognize bootable disk

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