The system now boots from a FAT12 file system!

SOURCE/BOOT.ASM

@@ -0,0 +1,176 @@
+[ORG 0x7c00]
+jmp short start
+nop
+
+;1.44 MB 3.5" floppy disk description table
+OEMLabel          db "EttinOS "
+BytesPerSector    dw 0x200
+SectorsPerCluster db 0x1
+BootRecordSectors dw 0x1
+FATs              db 0x2
+RootEntries       dw 0xe0
+LogicalSectors    dw 0xb40
+MediaDescriptor   db 0xf0
+SectorsPerFAT     dw 0x9
+SectorsPerTrack   dw 0x12
+Sides             dw 0x2
+HiddenSectors     dd 0x0
+LargeSectors      dd 0x0
+DriveNumber       dw 0x0
+DriveSignature    db 0x29
+VolumeID          dd 0x0
+VolumeLabel       db "EttinOS    "
+FileSystem        db "FAT12   "
+
+start:
+
+;Set up the data segment
+mov ax, 0x0
+mov ds, ax
+
+;Set up the stack
+cli
+mov ax, 0x0
+mov ss, ax
+mov sp, 0x7c00
+sti
+
+;Store the boot device number
+mov [bootdev], dl
+
+;Load the root FAT
+;Set the source
+mov ax, 0x13
+call calcsource
+;Set the destination
+mov si, 0x7e00
+mov bx, ds
+mov es, bx
+mov bx, si
+;Set the size
+mov al, 0xe
+;Load
+mov ah, 0x2
+int 0x13
+
+;Search the root FAT for the system
+;Set DI to the root FAT
+mov ax, ds
+mov es, ax
+mov di, 0x7e00
+;Initialise the search loop
+mov cx, word [RootEntries]
+mov ax, 0x0
+search:
+;Store CX in the stack
+push cx
+;Check for the binary
+mov si, sysfile
+mov cx, 0xb
+rep cmpsb
+je loadsysfat
+;Set DI to the next entry
+add ax, 0x20
+mov di, 0x7e00
+add di, ax
+;Load CX from the stack
+pop cx
+loop search
+
+;Load the system FAT
+loadsysfat:
+;???
+mov ax, word [es:di+0xf]
+mov word [cluster], ax
+;Set the source
+mov ax, 0x1
+call calcsource
+;Set the destination
+mov di, 0x7e00
+mov bx, di
+;Set the size
+mov al, 0x9
+;Load
+mov ah, 0x2
+int 0x13
+
+;Load the system
+loadsys:
+;Set the source
+mov ax, word [cluster]
+add ax, 0x1f
+call calcsource
+;Set the destination
+mov ax, 0x0
+mov es, ax
+mov bx, word [pointer]
+;Set the size
+mov al, 0x1
+;Load a cluster
+mov ah, 0x2
+int 0x13
+
+;Calculate the next cluster
+mov ax, [cluster]
+mov dx, 0x0
+mov bx, 0x3
+mul bx
+mov bx, 2
+div bx
+mov si, 0x7e00
+add si, ax
+mov ax, word [ds:si]
+or dx, dx
+jz even
+odd:
+shr ax, 4
+jmp contcluster
+even:
+and ax, 0xfff
+contcluster:
+mov word [cluster], ax
+cmp ax, 0xff8
+jge boot
+add word [pointer], 0x200
+jmp loadsys
+
+boot:
+jmp 0x0:0x9e00
+
+sysfile:
+db "SYSTEM  BIN"
+
+bootdev:
+db 0
+
+cluster:
+dw 0x0
+
+pointer:
+dw 0x9e00
+
+calcsource:
+push ax
+push bx
+mov bx, ax
+mov dx, 0x0
+div word [SectorsPerTrack]
+add dl, 0x1
+mov cl, dl
+mov ax, bx
+mov dx, 0x0
+div word [SectorsPerTrack]
+mov dx, 0x0
+div word [Sides]
+mov dh, dl
+mov ch, al
+pop bx
+pop ax
+mov dl, byte [bootdev]
+ret
+
+;Padding
+times 0x1fe-($-$$) db 0x0
+
+;Boot signature
+dw 0xaa55

SOURCE/BYTE2HEX.INC

@@ -1,6 +1,6 @@
 ;Converts a byte in ah to a hex string at di.
 
-byte2hexstr:
+byte2hex:
 
 ;Store the initial registers in the stack
 pusha

SOURCE/KEYCODE.INC

@@ -17,13 +17,13 @@ call printstr
 ;Convert the scancode to a hex string
 mov ah, [.scan]
 mov di, .keycode
-call byte2hexstr
+call byte2hex
 
 ;Convert the ascii value to a hex string
 mov ah, [.ascii]
 mov di, .keycode
 add di, 0x2
-call byte2hexstr
+call byte2hex
 
 ;Print the keycode
 mov si, .keycode

SOURCE/PRINTLN.INC

@@ -6,6 +6,6 @@ println:
 call printstr
 
 ;Print a newline
-call printcrlf
+call printnl
 
 ret

SOURCE/PRINTNL.INC

@@ -1,12 +1,12 @@
 ;Prints a newline
 
-printcrlf:
+printnl:
 
 ;Store the initial registers in the stack
 pusha
 
 ;Print the newline
-mov si, .crlf
+mov si, .nl
 call printstr
 
 ;Load the initial registers from the stack
@@ -14,5 +14,5 @@ popa
 
 ret
 
-.crlf:
+.nl:
 db 0xd, 0xa, 0x0

SOURCE/READLN.INC

@@ -6,6 +6,6 @@ readln:
 call readstr
 
 ;Print a newline
-call printcrlf
+call printnl
 
 ret

SOURCE/SYSTEM.ASM

@@ -1,20 +1,20 @@
-[ORG 0x7e00]
+[ORG 0x9e00]
 jmp start
 
 ;Calls
-%include "printcrlf.inc"
-%include "printstr.inc"
-%include "println.inc"
-%include "readstr.inc"
-%include "readln.inc"
-%include "cmpstr.inc"
-%include "byte2hexstr.inc"
+%include "PRINTNL.INC"
+%include "PRINTSTR.INC"
+%include "PRINTLN.INC"
+%include "READSTR.INC"
+%include "READLN.INC"
+%include "CMPSTR.INC"
+%include "BYTE2HEX.INC"
 
 ;Commands
-%include "echo.inc"
-%include "hello.inc"
-%include "help.inc"
-%include "keycode.inc"
+%include "ECHO.INC"
+%include "HELLO.INC"
+%include "HELP.INC"
+%include "KEYCODE.INC"
 
 start:
 

make.sh

@@ -1,8 +1,14 @@
 #!/bin/bash
 
-cd source/
-nasm boot.asm -f bin -O0 -o ../boot.bin
-nasm system.asm -f bin -O0 -o ../system.bin
+cd SOURCE/
+nasm BOOT.ASM -f bin -O0 -o ../BOOT.BIN
+nasm SYSTEM.ASM -f bin -O0 -o ../SYSTEM.BIN
 
 cd ..
-cat boot.bin system.bin > EttinOS.img
+if [[ -f EttinOS.img ]]
+then
+    rm EttinOS.img
+fi
+mkfs.fat -C EttinOS.img 1440
+mcopy -i EttinOS.img SYSTEM.BIN ::
+dd if=BOOT.BIN of=EttinOS.img conv=notrunc bs=512 count=1

source/boot.asm

@@ -1,60 +0,0 @@
-[ORG 0x7c00]
-jmp short start
-nop
-
-;Disk description table
-db "EttinOS "    ;Disk label
-dw 0x200         ;Bytes per sector
-db 0x1           ;Sectors per cluster
-dw 0x1           ;Sectors reserved for the boot record
-db 0x2           ;Number of copies of the FAT
-dw 0xe0          ;Number of directory entries
-dw 0xb40         ;Number of logical sectors
-db 0xf0          ;Media descriptor type
-dw 0x9           ;Sectors per FAT
-dw 0x12          ;Sectors per track
-dw 0x2           ;Number of heads
-dd 0x0           ;Number of hidden sectors
-dd 0x0           ;Number of LBA sectors
-dw 0x0           ;Drive number
-db 0x29          ;Drive signature
-dd 0x0           ;Volume ID
-db "EttinOS    " ;Volume label
-db "FAT12   "    ;File system type
-
-start:
-
-;Set up the data segment
-mov ax, 0x0
-mov ds, ax
-
-;Set up the stack
-cli
-mov ax, 0x0
-mov ss, ax
-mov sp, 0x7c00
-sti
-
-;Load the system
-;Set the source
-mov dh, 0x0
-mov ch, 0x0
-mov cl, 0x2
-;Set the destination
-mov ax, 0x0
-mov es, ax
-mov bx, 0x7e00
-;Set the size
-mov al, 0x5
-;Load
-mov ah, 0x2
-int 0x13
-
-;Boot the system
-jmp 0x0:0x7e00
-
-;Padding
-times 0x1fe-($-$$) db 0x0
-
-;Boot signature
-dw 0xaa55