Updated docs and 31_day

docs/_sidebar.md

@@ -7,6 +7,7 @@
   - [modifications](modifications.md)
   - [memory map](memory_map.md)
   - [HRB file format](hrb_format.md)
+  - [BPB](bpb.md)
   - [Q&A](Q&A.md)
   - [references](references.md)
 

docs/bpb.md

@@ -0,0 +1,115 @@
+# BIOS Parameter Block (BPB) structure
+
+- ORG 0x7c00: This sets the origin of the code to memory address 0x7c00. In the x86 architecture, the BIOS loads the boot sector of a bootable drive to this address and then transfers control to it.
+
+- JMP SHORT entry: A jump instruction to the entry label. This is a typical starting point in a boot sector to jump over the BPB structure and continue execution. entry is a label that would be defined later in the code.
+
+- NOP: A no-operation instruction, often used for padding.
+
+## Floppy Disk
+
+| Offset in Boot Sector | Length in Bytes | Mnemonic                                   | Data type | Data content  | Data comment                                                 |
+| --------------------- | --------------- | ------------------------------------------ | --------- | ------------- | ------------------------------------------------------------ |
+| 03                    | 8               | OEM_Identifier                             | DB        | "HARIBOTE"    | You can freely write the name of the boot sector (8 bytes)   |
+| 0B                    | 2               | BytesPerSector                             | DW        | 512           | Size of one sector (must be 512)                             |
+| 0D                    | 1               | SectorsPerCluster                          | DB        | 1             | Size of a cluster (must be 1 sector)                         |
+| 0E                    | 2               | ReservedSectors                            | DW        | 1             | Where the FAT starts (normally set to the first sector)      |
+| 10                    | 1               | NumberOfFATs                               | DB        | 2             | Number of FATs (must be 2)                                   |
+| 11                    | 2               | RootEntries                                | DW        | 224           | Size of the root directory area (usually set to 224 entries) |
+| 13                    | 2               | NumberOfSectors                            | DW        | 2880          | Size of this drive (must be 2880 sectors)                    |
+| 15                    | 1               | MediaDescriptor                            | DB        | 0xf0          | Type of media (must be 0xf0)                                 |
+| 16                    | 2               | SectorsPerFAT                              | DW        | 9             | Length of FAT area (must be 9 sectors)                       |
+| 18                    | 2               | SectorsPerHead                             | DW        | 18            | Number of sectors per track (must be 18)                     |
+| 1A                    | 2               | HeadsPerCylinder                           | DW        | 2             | Number of heads (must be 2)                                  |
+| 1C                    | 4               | HiddenSectors                              | DD        | 0             | Must be 0 as partitions are not used here                    |
+| 20                    | 4               | BigNumberOfSectors                         | DD        | 2880          | Write the size of this drive again                           |
+| 24                    | 1               | BIOS drive number                          | DB        | 0             |                                                              |
+| 25                    | 1               | Reserved                                   | DB        | 0             |                                                              |
+| 26                    | 1               | Extended Boot Record signature = 29h       | DB        | 0x29          | Apparently, it's good to set this value                      |
+| 27                    | 4               | Serial Number                              | DD        | 0xffffffff    | Probably the volume serial number                            |
+| 2B                    | 11              | Volume label                               | DB        | "HARIBOTEOS " | Name of the disk (11 bytes)                                  |
+| 36                    | 8               | System Identifier (FAT12, FAT16, or FAT32) | DB        | "FAT12 "      | Name of the format (8 bytes)                                 |
+
+## USB drive
+
+| Offset in Boot Sector | Length in Bytes | Mnemonic                                   | Data def       | Data type | Data content                                                   |
+| --------------------- | --------------- | ------------------------------------------ | -------------- | --------- | -------------------------------------------------------------- |
+| 03                    | 8               | OEM_Identifier                             | BS_OEMName     | DB        | "HARIBOTE" ; [8 bytes] boot sector name                        |
+| 0B                    | 2               | BytesPerSector                             | BPB_BytsPerSec | DW        | 0x0200 ; the size of a sector (should be 512=0x0020)           |
+| 0D                    | 1               | SectorsPerCluster                          | BPB_SecPerClus | DB        | 0x01 ; the size of a cluster (should be 1 sector)              |
+| 0E                    | 2               | ReservedSectors                            | BPB_RsvdSecCnt | DW        | 0x0001 ; where FAT begins (usually from 1st sector)            |
+| 10                    | 1               | NumberOfFATs                               | BPB_NumFATs    | DB        | 0x02 ; the number of FATs (should be 2)                        |
+| 11                    | 2               | RootEntries                                | BPB_RootEntCnt | DW        | 0x0000 ; the size of root directory area (usually 224 entries) |
+| 13                    | 2               | NumberOfSectors                            | BPB_TotSec16   | DW        | 0x0000 ; the size of this drive (should be 2880 sectors)       |
+| 15                    | 1               | MediaDescriptor                            | BPB_Media      | DB        | 0xf8 ; the type of media (Any Hard Drive)                      |
+| 16                    | 2               | SectorsPerFAT                              | BPB_FATSz16    | DW        | 0x0000 ; the length of FAT area (should be 9 sectors)          |
+| 18                    | 2               | SectorsPerHead                             | BPB_SecPerTrk  | DW        | 0xffff ; the number of sectors per a track (should be 18)      |
+| 1A                    | 2               | HeadsPerCylinder                           | BPB_NumHeads   | DW        | 0x0001 ; the number of heads (should be 2)                     |
+| 1C                    | 4               | HiddenSectors                              | BPB_HiDDSec    | DD        | 0x00000000 ; should be zero since we will not use partition    |
+| 20                    | 4               | BigNumberOfSectors                         | BPB_TotSec32   | DD        | 0x00ee5000 ; the size of this drive (again)                    |
+| 24                    | 4               | BigSectorsPerFAT                           | BPB_FATSz32    | DD        | 0x000000ed                                                     |
+| 28                    | 2               | ExtFlags                                   | BPB_ExtFlags   | DW        | 0x0000                                                         |
+| 2A                    | 2               | FSVersion                                  | BPB_FSVer      | DW        | 0x0000                                                         |
+| 2C                    | 4               | RootDirectoryStart                         | BPB_RootClus   | DD        | 0x00000000                                                     |
+| 30                    | 2               | FSInfoSector                               | BPB_FSInfo     | DW        | 0x0001                                                         |
+| 32                    | 2               | BackupBootSector                           | BPB_BkBootSec  | DW        | 0x0000                                                         |
+| 34                    | 12              | Reserved                                   |                |           | TIMES 12 DB 0 ; BPB_Reserved                                   |
+| 40                    | 1               | BIOS drive number                          | BS_DrvNum      | DB        | 0x80                                                           |
+| 41                    | 1               | Reserved                                   | BS_Reserved1   | DB        | 0x00                                                           |
+| 42                    | 1               | Extended Boot Record signature = 29h       | BS_BootSig     | DB        | 0x29                                                           |
+| 43                    | 4               | Serial Number                              | BS_VolID       | DD        | 0xffffffff                                                     |
+| 47                    | 11              | Volume label                               | BS_VolLab      | DB        | "HARIBOTEOS " ; [11 bytes] the name of the disk                |
+| 52                    | 8               | System Identifier (FAT12, FAT16, or FAT32) | BS_FilSysType  | DB        | "FAT32 " ; [8 bytes] the name of the format                    |
+
+### Calculations and Explanations
+
+1.  Bytes per Sector (BPB_BytsPerSec):
+
+    - Fixed at 512 bytes per sector (0x0200).
+
+2.  Sectors per Cluster (BPB_SecPerClus):
+
+    - Typically 8 sectors per cluster (0x08) for FAT32 on a large drive like 8GB.
+
+3.  Reserved Sectors Count (BPB_RsvdSecCnt):
+
+    - Typically 32 reserved sectors (0x0020) for FAT32.
+
+4.  Total Sectors (BPB_TotSec32):
+
+    - 8GB drive = 8 \* 1024 \* 1024 \* 1024 bytes.
+    - Total sectors = 8 \* 1024 \* 1024 \* 1024 / 512 = 16,777,216 sectors.
+    - However, since the actual usable sectors are a bit less due to reserved sectors, let's use a practical value of 7,745,024 sectors (0x00EE5000).
+
+5.  Sectors per FAT (BPB_FATSz32):
+
+    This requires a bit of calculation:
+
+    - Number of Clusters = (Total Sectors - Reserved Sectors - (Number of FATs \* Sectors per FAT) - Root Directory Sectors) / Sectors per Cluster
+
+    Estimating Sectors per FAT:
+
+    - Assume 8,000 sectors per FAT initially (0x1F40).
+
+    Adjust if necessary after calculating the number of clusters.
+
+6.  Sectors per Track (BPB_SecPerTrk) and Number of Heads (BPB_NumHeads):
+
+    - These are more relevant to older BIOS geometry but typically set as 63 sectors per track and 255 heads for modern USB drives.
+
+7.  Hidden Sectors (BPB_HiDDSec):
+
+    - Usually set to 0.
+
+8.  FAT32-specific fields:
+
+    - `BPB_RootClus` typically starts at cluster 2.
+    - `BPB_FSInfo` usually 1.
+    - `BPB_BkBootSec` usually 6.
+
+## References
+
+- https://en.wikipedia.org/wiki/BIOS_parameter_block
+- https://averstak.tripod.com/fatdox/bootsec.htm
+- https://academy.cba.mit.edu/classes/networking_communications/SD/FAT.pdf
+- https://wiki.osdev.org/FAT

projects/31_day/harib28a/Makefile

@@ -203,10 +203,10 @@ haribote.iso: haribote.img
 	# hdiutil makehybrid -iso -joliet -o $@ $<
 	mkisofs -b $< -o $@ -input-charset utf8 $<
 
-run-cd: full haribote.iso
+run_cd: full haribote.iso
 	qemu-system-i386 -boot d -cdrom haribote.iso -m 32
 
-run-usb: full-usb usb.img
+run_usb: full_usb usb.img
 	qemu-system-i386 $(QEMU_FLAGS) -m 32 -vga std \
 	-drive file=usb.img,format=raw,if=none,id=usbdrive \
 	-device usb-ehci -device usb-storage,drive=usbdrive
@@ -245,7 +245,7 @@ full:
 	$(MAKE) -C gview
 	$(MAKE) haribote.img
 
-full-usb:
+full_usb:
 	$(MAKE) -C haribote usb
 	$(MAKE) -C apilib
 	$(MAKE) -C a
@@ -281,7 +281,7 @@ full-usb:
 
 run_full: full run
 
-run-usb_full: full-usb run-usb
+run_full_usb: full_usb run_usb
 
 run_os: haribote.img run
 

projects/31_day/harib28a/haribote/Makefile

@@ -80,6 +80,7 @@ haribote.sys: asmhead.bin bootpack.hrb
 
 %.bin: %.nas
 	$(NASM) $(NASM_FLAGS) -f bin -o $@ $< -l $*.lst
+	ndisasm -b 32 $*.bin > $*.map
 
 %.obj: %.nas
 	$(NASM) $(NASM_FLAGS) -f elf32 -o $@ $< -l $*.lst

projects/31_day/harib28a/haribote/asmhead.nas

@@ -24,7 +24,7 @@ SCRNY	EQU		0x0ff6			; 
 VRAM	EQU		0x0ff8			; グラフィックバッファの開始番地
 
 		ORG		0xc200			; このプログラムがどこに読み込まれるのか
-
+; JMP scrn320
 ; VBE存在確認
 
 		MOV		AX,0x9000

projects/31_day/harib28a/haribote/ipl09.nas

@@ -1,54 +1,54 @@
 ; haribote-ipl
 ; TAB=4
 
-CYLS	EQU		15				; どこまで読み込むか
+CYLS	EQU		15				; How far to read
 
-		ORG		0x7c00			; このプログラムがどこに読み込まれるのか
+		ORG		0x7c00			; Where this program will be loaded
 
-; 以下は標準的なFAT12フォーマットフロッピーディスクのための記述
+; The following is for a standard FAT12 format floppy disk
 
 		JMP		entry
 		DB		0x90
-		DB		"HARIBOTE"		; ブートセクタの名前を自由に書いてよい（8バイト）
-		DW		512				; 1セクタの大きさ（512にしなければいけない）
-		DB		1				; クラスタの大きさ（1セクタにしなければいけない）
-		DW		1				; FATがどこから始まるか（普通は1セクタ目からにする）
-		DB		2				; FATの個数（2にしなければいけない）
-		DW		224				; ルートディレクトリ領域の大きさ（普通は224エントリにする）
-		DW		2880			; このドライブの大きさ（2880セクタにしなければいけない）
-		DB		0xf0			; メディアのタイプ（0xf0にしなければいけない）
-		DW		9				; FAT領域の長さ（9セクタにしなければいけない）
-		DW		18				; 1トラックにいくつのセクタがあるか（18にしなければいけない）
-		DW		2				; ヘッドの数（2にしなければいけない）
-		DD		0				; パーティションを使ってないのでここは必ず0
-		DD		2880			; このドライブ大きさをもう一度書く
-		DB		0,0,0x29		; よくわからないけどこの値にしておくといいらしい
-		DD		0xffffffff		; たぶんボリュームシリアル番号
-		DB		"HARIBOTEOS "	; ディスクの名前（11バイト）
-		DB		"FAT12   "		; フォーマットの名前（8バイト）
-		RESB	18				; とりあえず18バイトあけておく
-
-; プログラム本体
+		DB		"HARIBOTE"		; You can freely write the name of the boot sector (8 bytes)
+		DW		512				; Size of one sector (must be 512)
+		DB		1				; Size of a cluster (must be 1 sector)
+		DW		1				; Where the FAT starts (normally set to the first sector)
+		DB		2				; Number of FATs (must be 2)
+		DW		224				; Size of the root directory area (usually set to 224 entries)
+		DW		2880			; Size of this drive (must be 2880 sectors)
+		DB		0xf0			; Type of media (must be 0xf0)
+		DW		9				; Length of FAT area (must be 9 sectors)
+		DW		18				; Number of sectors per track (must be 18)
+		DW		2				; Number of heads (must be 2)
+		DD		0				; Must be 0 as partitions are not used here
+		DD		2880			; Write the size of this drive again
+		DB		0,0,0x29		; Apparently, it's good to set this value
+		DD		0xffffffff		; Probably the volume serial number
+		DB		"HARIBOTEOS "	; Name of the disk (11 bytes)
+		DB		"FAT12   "		; Name of the format (8 bytes)
+		RESB	18				; Leave 18 bytes for now
+
+; Main program
 
 entry:
-		MOV		AX,0			; レジスタ初期化
+		MOV		AX,0			; Initialize registers
 		MOV		SS,AX
 		MOV		SP,0x7c00
 		MOV		DS,AX
 
-; ディスクを読む
+; Read the disk
 
 		MOV		AX,0x0820
 		MOV		ES,AX
-		MOV		CH,0			; シリンダ0
-		MOV		DH,0			; ヘッド0
-		MOV		CL,2			; セクタ2
-		MOV		BX,18*2*CYLS-1	; 読み込みたい合計セクタ数
-		CALL	readfast		; 高速読み込み
+		MOV		CH,0			; Cylinder 0
+		MOV		DH,0			; Head 0
+		MOV		CL,2			; Sector 2
+		MOV		BX,18*2*CYLS-1	; Total number of sectors to read
+		CALL	readfast		; Fast reading
 
-; 読み終わったのでharibote.sysを実行だ！
+; After reading, execute haribote.sys!
 
-		MOV		BYTE [0x0ff0],CYLS	; IPLがどこまで読んだのかをメモ
+		MOV		BYTE [0x0ff0],CYLS	; Note how far the IPL has read
 		JMP		0xc200
 
 error:
@@ -57,32 +57,32 @@ error:
 		MOV		SI,msg
 putloop:
 		MOV		AL,[SI]
-		ADD		SI,1			; SIに1を足す
+		ADD		SI,1			; Add 1 to SI
 		CMP		AL,0
 		JE		fin
-		MOV		AH,0x0e			; 一文字表示ファンクション
-		MOV		BX,15			; カラーコード
-		INT		0x10			; ビデオBIOS呼び出し
+		MOV		AH,0x0e			; Display one character function
+		MOV		BX,15			; Color code
+		INT		0x10			; Call video BIOS
 		JMP		putloop
 fin:
-		HLT						; 何かあるまでCPUを停止させる
-		JMP		fin				; 無限ループ
+		HLT						; Halt the CPU until something happens
+		JMP		fin				; Infinite loop
 msg:
-		DB		0x0a, 0x0a		; 改行を2つ
+		DB		0x0a, 0x0a		; Two newlines
 		DB		"load error"
-		DB		0x0a			; 改行
+		DB		0x0a			; Newline
 		DB		0
 
-readfast:	; ALを使ってできるだけまとめて読み出す
-;	ES:読み込み番地, CH:シリンダ, DH:ヘッド, CL:セクタ, BX:読み込みセクタ数
+readfast:	; Use AL to read as much as possible at once
+;	ES: Read address, CH: Cylinder, DH: Head, CL: Sector, BX: Number of sectors to read
 
-		MOV		AX,ES			; < ESからALの最大値を計算 >
-		SHL		AX,3			; AXを32で割って、その結果をAHに入れたことになる （SHLは左シフト命令）
-		AND		AH,0x7f			; AHはAHを128で割った余り（512*128=64K）
-		MOV		AL,128			; AL = 128 - AH; 一番近い64KB境界まで最大何セクタ入るか
+		MOV		AX,ES			; < Calculate the maximum value of AL from ES >
+		SHL		AX,3			; Divide AX by 32 and store the result in AH (SHL is the left shift instruction)
+		AND		AH,0x7f			; AH is the remainder of AH divided by 128 (512*128=64K)
+		MOV		AL,128			; AL = 128 - AH; Maximum number of sectors up to the nearest 64KB boundary
 		SUB		AL,AH
 
-		MOV		AH,BL			; < BXからALの最大値をAHに計算 >
+		MOV		AH,BL			; < Calculate the maximum value of AL from BX to AH >
 		CMP		BH,0			; if (BH != 0) { AH = 18; }
 		JE		.skip1
 		MOV		AH,18
@@ -92,31 +92,31 @@ readfast:	; AL
 		MOV		AL,AH
 .skip2:
 
-		MOV		AH,19			; < CLからALの最大値をAHに計算 >
+		MOV		AH,19			; < Calculate the maximum value of AL from CL to AH >
 		SUB		AH,CL			; AH = 19 - CL;
 		CMP		AL,AH			; if (AL > AH) { AL = AH; }
 		JBE		.skip3
 		MOV		AL,AH
 .skip3:
 
 		PUSH	BX
-		MOV		SI,0			; 失敗回数を数えるレジスタ
+		MOV		SI,0			; Register to count the number of failures
 retry:
-		MOV		AH,0x02			; AH=0x02 : ディスク読み込み
+		MOV		AH,0x02			; AH=0x02 : Disk read
 		MOV		BX,0
-		MOV		DL,0x00			; Aドライブ
+		MOV		DL,0x00			; Drive A
 		PUSH	ES
 		PUSH	DX
 		PUSH	CX
 		PUSH	AX
-		INT		0x13			; ディスクBIOS呼び出し
-		JNC		next			; エラーがおきなければnextへ
-		ADD		SI,1			; SIに1を足す
-		CMP		SI,5			; SIと5を比較
-		JAE		error			; SI >= 5 だったらerrorへ
+		INT		0x13			; Call disk BIOS
+		JNC		next			; If no error, go to next
+		ADD		SI,1			; Add 1 to SI
+		CMP		SI,5			; Compare SI with 5
+		JAE		error			; If SI >= 5, go to error
 		MOV		AH,0x00
-		MOV		DL,0x00			; Aドライブ
-		INT		0x13			; ドライブのリセット
+		MOV		DL,0x00			; Drive A
+		INT		0x13			; Reset the drive
 		POP		AX
 		POP		CX
 		POP		DX
@@ -126,28 +126,28 @@ next:
 		POP		AX
 		POP		CX
 		POP		DX
-		POP		BX				; ESの内容をBXで受け取る
-		SHR		BX,5			; BXを16バイト単位から512バイト単位へ
+		POP		BX				; Receive the contents of ES in BX
+		SHR		BX,5			; Convert BX from 16-byte units to 512-byte units
 		MOV		AH,0
 		ADD		BX,AX			; BX += AL;
-		SHL		BX,5			; BXを512バイト単位から16バイト単位へ
-		MOV		ES,BX			; これで ES += AL * 0x20; になる
+		SHL		BX,5			; Convert BX from 512-byte units to 16-byte units
+		MOV		ES,BX			; This makes ES += AL * 0x20;
 		POP		BX
 		SUB		BX,AX
 		JZ		.ret
-		ADD		CL,AL			; CLにALを足す
-		CMP		CL,18			; CLと18を比較
-		JBE		readfast		; CL <= 18 だったらreadfastへ
+		ADD		CL,AL			; Add AL to CL
+		CMP		CL,18			; Compare CL with 18
+		JBE		readfast		; If CL <= 18, go to readfast
 		MOV		CL,1
 		ADD		DH,1
 		CMP		DH,2
-		JB		readfast		; DH < 2 だったらreadfastへ
+		JB		readfast		; If DH < 2, go to readfast
 		MOV		DH,0
 		ADD		CH,1
 		JMP		readfast
 .ret:
 		RET
 
-		RESB	0x7dfe-0x7c00-($-$$)		; 0x7dfeまでを0x00で埋める命令
+		RESB	0x7dfe-0x7c00-($-$$)		; Fill with 0x00 up to 0x7dfe
 
 		DB		0x55, 0xaa