Began moving to C. (No C yet)

If you want to build the assembly version, run the buildAsm.sh script
Currently just setting up the bootloader.

asmSrc/lib/disk.asm

@@ -0,0 +1,331 @@
+;
+; Loads a file from the filetable into a memory location
+; Params:
+;   dl - Disk number
+;   Filename (Null terminated)
+;   Destination location segment
+;   Destination location offset
+;
+; Returns:
+;   al - Exit code : 0 - Success; 1 - File not found; 2 - Disk error
+;
+loadFile:
+    ; Func prologue
+    push bp
+    mov bp, sp
+    push bx
+    push fs
+    push cx
+    push dx
+    push si
+    push es
+
+    mov byte [diskNum], dl
+    mov bx, [bp+4]      ; src Offset
+    mov fs, [bp+6]      ; src Segment
+    mov si, [bp+8]      ; Filename
+
+    push bx
+
+    mov cx, 10
+    mov di, fileName
+.getFilename:
+    lodsb           ; mov byte al, [si]; inc si
+    cmp al, 0       ; End of fileName
+    je .filenamePad
+    stosb
+    loop .getFilename
+    jmp .filenameDone
+.filenamePad: 
+    dec si          ; Fill the rest with Null
+.filenamePadLoop:
+    stosb
+    loop .filenamePadLoop
+.filenameDone:
+    mov ax, FILETAB_LOC
+    mov es, ax
+    xor di, di      ; es:di - Filetable location
+    mov si, fileName
+.fileNameCheck:
+    mov al, [es:di]
+    cmp al, 0       ; End of filetable
+    je .notFound
+
+    cmp al, [si]
+    je .beginCmp
+
+    add di, 16
+    jmp .fileNameCheck
+.beginCmp:
+    push di
+    mov cl, 10
+.cmpLoop:
+    mov al, [es:di]
+    inc di
+    cmp al, [si]
+    jne .redoCheck
+
+    dec cl 
+    jz .found
+    inc si
+    jmp .cmpLoop
+.redoCheck:
+    mov si, fileName
+    pop di
+    add di, 16
+    jmp .fileNameCheck
+.notFound:
+    mov byte [exitCode], NOT_FOUND
+    jmp .done
+.found:
+    add di, 3       ; Skip extension
+    inc di          ; Skip Number of entries
+
+    xor ax, ax      ; Reset disk
+    mov dl, [diskNum]
+    int 0x13
+
+    mov ch, 0       ; Cylinder
+    mov dh, 0       ; Head
+    mov cl, [es:di] ; Sector
+    inc di
+    mov al, [es:di] ; Length in sectors
+    mov bx, fs
+    mov es, bx
+    pop bx
+    mov dx, bx
+    call printHexByte
+    mov ah, 2       ; Read from disk
+    int 0x13
+
+    jnc .done
+
+    mov byte [exitCode], DISK_ERROR
+.done:
+    ; Func epilogue
+    pop es
+    pop si
+    pop dx
+    pop cx
+    pop fs
+    pop bx
+    mov sp, bp
+    pop bp
+    mov byte al, [exitCode]
+    ret
+
+;
+; Saves a file to the disk and updates filetable
+; dl - Disk number
+; Params:
+;   Filename (Null terminated)
+;   Filetype (Null terminated)
+;   Filesize (Byte)
+;   Source location segment
+;   Source location offset
+;
+; Returns:
+;   al - Exit code : 0 - Success; 1 - File not found; 2 - Disk error
+;
+saveFile:
+    ; Func prologue
+    push bp
+    mov bp, sp
+    push bx
+    push fs
+    push cx
+    push dx
+    push si
+    push es
+
+    mov byte [diskNum], dl
+    mov bx, [bp+4]      ; src Offset
+    mov fs, [bp+6]      ; src Segment
+    mov cx, [bp+8]      ; Filesize 
+    mov ax, [bp+10]     ; Filetype
+
+    push bx
+
+    mov byte [filesize], cl
+
+    mov si, ax
+    mov di, filetype
+    mov cx, 3
+    rep movsb
+
+    mov si, [bp+12] ; Filename
+    mov cx, 10
+    mov di, fileName
+.getFilename:
+    lodsb           ; mov byte al, [si]; inc si
+    cmp al, 0       ; End of fileName
+    je .filenamePad
+    stosb
+    loop .getFilename
+    jmp .filenameDone
+.filenamePad: 
+    dec si          ; Fill the rest with Null
+.filenamePadLoop:
+    stosb
+    loop .filenamePadLoop
+.filenameDone:
+    mov ax, FILETAB_LOC
+    mov es, ax
+    xor di, di      ; es:di - Filetable location
+    mov si, fileName
+.fileNameCheck:
+    mov byte al, [es:di+14] ; Starting sector
+    cmp al, 0       ; No file, create one
+    je createFile
+
+    add byte al, [es:di+15] ; Filesize 
+    mov byte [availableSector], al
+
+    mov al, [es:di]
+    cmp al, 0       ; End of filetable
+    je createFile   ; File doesn't exist, create new one
+
+    cmp al, [si]
+    je .beginCmp
+
+    add di, 16
+    jmp .fileNameCheck
+.beginCmp:
+    push di
+    mov cl, 10
+.cmpLoop:
+    mov al, [es:di]
+    inc di
+    cmp al, [si]
+    jne .redoCheck
+
+    dec cl 
+    jz .found
+    inc si
+    jmp .cmpLoop
+.redoCheck:
+    mov si, fileName
+    pop di
+    add di, 16
+    jmp .fileNameCheck
+.found:             ; File already exists (override)
+    ; TODO: Ask user if they want to override file
+    add di, 3       ; Skip extension
+    inc di          ; Skip Number of entries
+
+    xor ax, ax      ; Reset disk
+    mov dl, [diskNum]
+    int 0x13
+
+    ; TODO: Override current file
+    ; push fs
+    ; mov ch, 0       ; Cylinder
+    ; mov dh, 0       ; Head
+    ; mov cl, [es:di] ; Sector
+    ; inc di
+    ; mov al, [es:di] ; Length in sectors
+    ; mov ah, 3       ; Write to disk
+    ; pop es          ; es:bx - Destination
+    ; int 0x13
+
+    ; jnc returnToCaller
+
+    mov byte [exitCode], DISK_ERROR
+    jmp returnToCaller  ; TODO: Fix this
+
+createFile:             ; Appends a file to the filetable.
+    mov di, FILETAB_LOC
+    mov es, di
+    xor di, di
+
+.filetabEnd:            ; Move to the end of filetable
+    cmp byte [es:di], 0
+    je .filetabEndDone
+    add di, 16
+    jmp .filetabEnd
+.filetabEndDone:
+    mov cx, 10
+    mov si, fileName
+    rep movsb           ; Append the fileName
+    mov cx, 3
+    mov si, filetype
+    rep movsb           ; Append the extension
+    mov byte [es:di], 0 ; Number of entries
+    inc di
+    mov byte al, [availableSector]
+    stosb               ; Starting sector
+    mov byte al, [filesize]
+    stosb               ; File length in sectors
+
+    ; Write changed filetable to disk
+    ;! If filetable size changes, this will have to change (probably)
+    mov bx, FILETAB_LOC
+    mov es, bx
+    xor bx, bx          ; es:bx - Filetable location
+    mov dl, [diskNum]
+    mov ah, 3           ; Write to disk
+    mov al, 1           ; Write 1 sector
+    mov ch, 0           ; Cylinder
+    mov dh, 0           ; Head
+    mov cl, 2           ; Sector
+    int 0x13
+
+    jnc writeFileData
+
+    mov byte [exitCode], DISK_ERROR
+    jmp returnToCaller
+
+writeFileData:          ; Writes file data to the disk
+    mov ax, 0x8000          ; Source segment
+    mov es, ax
+    pop bx              ; es:bx - Source
+    mov ah, 3           ; Write to disk
+    mov byte al, [filesize]
+    mov dl, [diskNum]
+    mov ch, 0           ; Cylinder
+    mov dh, 0           ; Head
+    mov byte cl, [availableSector]
+    int 0x13
+
+    jnc returnToCaller
+
+    mov byte [exitCode], DISK_ERROR  ; Exit code - Disk Error
+
+returnToCaller:
+    ; Func epilogue
+    pop es
+    pop si
+    pop dx
+    pop cx
+    pop fs
+    pop bx
+    mov sp, bp
+    pop bp
+    mov byte al, [exitCode]
+    ret
+
+;
+; Removes a file from the disk/filetable
+;
+; Params:
+;   Filename
+;
+removeFile:
+    
+
+;; Variables
+availableSector: db 0
+exitCode: db 0
+
+diskNum: db 0
+filesize: db 0
+filetype: times 3 db 0
+fileName: times 10 db 0
+
+;; Constants
+FILETAB_LOC equ 0x1000
+
+; Exit codes
+SUCCESS equ 0
+NOT_FOUND equ 1
+DISK_ERROR equ 2

asmSrc/lib/print.asm

@@ -0,0 +1,129 @@
+;
+; Prints a string
+; si - Pointer to NULL terminated string
+;
+print:
+    pusha
+    mov ah, 0x0e
+    mov bl, 0x1f
+    mov bh, 0
+.loop:
+    lodsb           ; Load [si] into al; Increment si
+    or al, al
+    jz .done
+    int 0x10
+    jmp .loop
+.done:
+    popa
+    ret
+
+;
+; Prints a hex value
+; dx - Value to print in Hex
+;
+printHex:
+    pusha
+    xor cx, cx      ; Init counter
+.loop:
+    cmp cx, 4       ; Check for loop end
+    je .done
+    mov ax, dx      ; Copy dx to ax
+    and ax, 0x000f  ; Get last nibble (4 bits) of ax
+    add ax, '0'     ; Convert number to an ASCII number (0-9)
+    cmp ax, '9'     ; Check if number was less than 9, meaning we can use it
+    jle .addChar
+    add ax, 0x07    ; Convert to letter (A-F)
+.addChar:
+    mov bx, hexString + 5
+    sub bx, cx      ; Get position of current hex character
+    mov [bx], al
+    ror dx, 4       ; Rotate bits of dx (0x1a2b -> 0xb1a2)
+    inc cx          ; Increment the counter
+    jmp .loop
+.done: 
+    mov si, hexString
+    call print
+    popa
+    ret
+
+;
+; Prints a hex byte
+; dl - Hex byte
+;
+printHexByte:
+    pusha
+    xor cx, cx
+    mov bh, 0
+    mov bl, 0x1f    ; White on blue
+.loop:
+    mov al, dl
+    and al, 0xF0
+    ror al, 4
+    add al, '0'
+    cmp al, '9'
+    jle .hexNum
+    add al, 7
+.hexNum:
+    mov ah, 0x0e
+    int 0x10
+    inc cx
+    cmp cx, 2
+    je .done
+    ror dl, 4
+    jmp .loop
+.done:
+    popa
+    ret
+
+hexString: db "0x0000", 0
+
+;
+; Clears the screen in text mode
+; Assumes VGA text 3 - 80x25, 16 color
+;
+clearText:
+    pusha
+    push es
+    mov ax, 0x0b800
+    mov es, ax
+    xor di, di      ; es:di - b800:0000
+
+    mov al, ' '     ; Fill with spaces
+    mov ah, 0x17    ; White on blue
+    mov cx, 80*25 
+    rep stosw 
+
+    mov ah, 2
+    xor dx, dx      ; Set cursor to 0,0
+    int 0x10
+
+    pop es
+    popa
+    ret
+
+;
+; Writes a string into video memory
+; di - Video memory offset
+; si - string
+;
+drawString:
+    pusha
+    push es         ; For some reason doesn't get stored in pusha
+    mov ax, VIDMEM
+    mov es, ax
+.loop:
+    cmp byte [si], 0
+    je .after
+    movsb
+    mov byte [es:di], 0x1f  ; White on blue
+    inc di
+    jmp .loop
+.after:
+    pop es
+    popa
+    ret
+
+; Usefull definitions
+%define ENDL 0x0a, 0x0d
+VIDMEM equ 0x0b800
+newline: db ENDL, 0 ; CRLF

asmSrc/lib/screen.asm

@@ -0,0 +1,24 @@
+resetTextMode: 
+    pusha
+
+    mov ah, 0       ; Set mode
+    mov al, 0x03    ; 25x80, Text mode
+    int 0x10
+
+    mov ah, 0x0b    ; Change color/palette
+    mov bh, 0x00    ; Change BG color
+    mov bl, 0x01    ; Blue BG
+    int 0x10
+
+    popa
+    ret
+
+resetGraphicsMode:
+    pusha
+
+    mov ah, 0       ; Set mode
+    mov al, 0x13    ; 320x200, 256 color graphics mode
+    int 0x10
+
+    popa
+    ret