idk what i added

source/kernel/features/strings.asm

@@ -62,8 +62,7 @@ os_format_fat_filename:
    pusha
    call os_upper_case
    call os_string_length ; Stores the length of the string in cl
-   mov bl, 11
-   sub bl, cl ; 11 - string_length
+   xor ch,ch ; Clear ch to reset it to 0
    .character_loop:
 	  lodsb
 	  cmp al, 0
@@ -71,10 +70,18 @@ os_format_fat_filename:
 	  cmp al, 2Eh ; 2Eh
 	  je .add_spaces ; This will end up back at .character_loop
 	  stosb
+	  inc ch
 	  jmp .character_loop
 
    .add_spaces: ; Add the number of spaces as bl holds
 	  mov al, ' ' ; 20h = space
+
+	  ; Work out the number of spaces in between
+	  ; the name and extension.
+	  ; 8 - name_length(ch)
+	  xor bl, bl
+	  sub bl, ch
+	  add bl, 7
 	  .spaces_loop:
 		 stosb
 		 cmp bl, 0
@@ -85,6 +92,58 @@ os_format_fat_filename:
 	  popa
 	  ret
 
+; Does the inverse of the previous
+; Converts a fat filename back to human readable
+; eg. 'KERNEL  BIN' -> 'KERNEL.BIN'
+; input: si points to fat filename (11 bytes)
+; output: 
+; di points to the unformatted filename
+; [file_name_length] stores the length of the filename
+string_unformat_fat_filename:
+	pusha
+
+	xor ax,ax
+	xor dx,dx
+	mov cx, 11 ; Counter
+	.name_loop:
+		lodsb
+		stosb
+		dec cx
+		inc dx
+		cmp cx, 3
+		jne .name_loop
+	push si
+	mov si, di
+	.space_loop:
+		dec si
+		lodsb
+		dec si
+		dec dx
+		cmp al, 20h ; Space
+		je .space_loop
+		jmp .insert_stop
+	.insert_stop:
+		mov di, si
+		inc di
+		inc dx
+		pop si
+		mov al, 2Eh
+		stosb
+	mov cx, 3
+	.extension_loop:
+		lodsb
+		stosb
+		dec cx
+		inc dx
+		cmp cx, 0
+		jne .extension_loop
+
+	.finish:
+		inc dx
+		mov [file_name_length], dx
+		popa
+		ret
+
 ; Convert a string to all upper/lower case
 ; INPUT: si pointing to a string
 ; OUPUT: the same string in memory will now be capitalised/decapitalised