; ****************************************************************************
;
; BOOT1.ASM (Only for bootable UNIX v1 file system on 1.44 MB Floppy Disks)
; ----------------------------------------------------------------------------
;
; RETRO UNIX 8086 (Retro Unix == Turkish Rational Unix)
; Operating System Project (v0.1) by ERDOGAN TAN (Beginning: 11/07/2012) 
; 1.44 MB Floppy Disk 
; Bootable Unix (RUFS) File System - UNIX Kernel Loader (Boot) File
; 07/03/2013
; Derived from UNIXCOPY.ASM (25/02/2013) 
;
; [ Last Modification: 05/03/2016 ]
;
; Retro Unix is a derivation from UNIX Operating System (v1.0 for PDP-11) 
; (Original) Source Code by Ken Thompson (1971-1972)
; <Bell Laboratories (17/3/1972)>
; <Preliminary Release of UNIX Implementation Document>
;
; ****************************************************************************

bsFSystemID     equ 2  ; 'RUFS' 
bsVolumeSerial  equ 6  ; (4 bytes)
bsFDSign        equ 10 ; 'fd'
bsDriveNumber   equ 12 ; fd0 or fd1 (0 or 1)
bsReserved      equ 13 ; 0 (512 bytes per sector)       
bsSecPerTrack   equ 14 ; 18 (9 or 15)   
bsHeads         equ 15 ; 2
bsTracks        equ 16 ; 80
bs_bf_inode_number equ 18 ; 0 or Boot/Startup File I-Number
bsInfoEndsign   equ 20 ; '@'

ROOT_DIR_INODE_NUMBER equ 41

kernel_loading_segment equ 1000h ; 09/07/2013
       ;; boot file space (segment 7E0h) = 33280 bytes, 
       ;; kernel space (segment 1000h) = 65536 bytes
;;kernel_loading_segment equ 1800h  ; 05/03/2013

.8086

BOOT1  SEGMENT PUBLIC 'CODE'
		assume cs:BOOT1,ds:BOOT1,es:BOOT1,ss:BOOT1

START_CODE:

proc_start  proc near
		; 07/03/2013 (timer)
		; 06/03/2013
		; 05/03/2013
		; 01/03/2013
		; 25/02/2013
		; 24/02/2013 (BOOT1.ASM)
		; 08/12/2012 (UNIXCOPY)
		;
		; 30/11/2012 (UNIXBOOT)
		;

		mov ax, offset EndOfFile
		mov word ptr [BSBUFFER], ax
		add ax, 512
		mov word ptr [SUPERBLOCK], ax
		add ax, 512
		mov word ptr [DISKBUFFER], ax
		add ax, 512
		mov word ptr [FILEBUFFER], ax

loc_copy_bootsector:
		; cli
		;mov ax, cs
		;mov sp, sizeoffile + 1000h  
		;mov ss, ax
		;mov es, ax
		;mov ds, ax
		;sti
		; cld
		;xor cx, cx
		;mov ds, cx
		mov ax, ds
		mov cx, 7C0h
		mov ds, cx
		xor si, si
		mov di, offset EndOfFile ; word ptr [BSBUFFER]
		mov cx, 256
		rep movsw
		
		mov ds, ax
		mov word ptr [EXTRA_SEGMENT], ax ; RESET ; 06/03/2013
	      
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
; Read Superblock
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
; 25/02/2013
loc_read_superblock:
		; DL = Drive number
		mov byte ptr [PhysicalDriveNumber], dl
		mov bx, word ptr [SUPERBLOCK]
		mov ax,0201h  ; Read 1 sector
		;mov cx,2 ; Read superblock
		mov cl, 2 ; 07/03/2013 (ch=0)
		xor dh,dh
		int 13h
		jnc short loc_unix_welcome

loc_drv_read_error:
		mov si, offset msg_unix_drv_read_error
		call UNIX_PRINTMSG

		xor ah, ah
		int 16h

		int 19h
 
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
; Write message
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

loc_unix_welcome:
		mov si, offset UNIX_Welcome
		call UNIX_PRINTMSG

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
; Timer
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

; 07/03/2013
; Automatic (default) kernel loading with timer tick count

		mov ax, ds ; cs
		mov cx, 40h
		mov es, cx
		mov bx, 6Ch
		mov cx, word ptr ES:[BX]
		add cx, 182*6 ; 60 seconds ? 
		mov word ptr [waiting_count], cx
		mov es, ax

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
; call command interpreter
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

loc_call_unix_prompt:
		call unix_prompt

		int 19h

proc_start endp


UNIX_PRINTMSG proc near
		; 20/01/2013 'call unix_printchr'
 
UNIX_PRINTMSG_LOOP:
		lodsb                           ; Load byte at DS:SI to AL
		and     AL,AL            
		jz      short UNIX_PRINTMSG_OK
		mov     AH,0Eh                  
		mov     BX,07h             
		int     10h                     ; BIOS Service func ( ah ) = 0Eh
						; Write char as TTY
						;AL-char BH-page BL-colo
		;call   unix_printchr           ; 20/01/2013
		jmp     short UNIX_PRINTMSG_LOOP           

UNIX_PRINTMSG_OK:
		retn

UNIX_PRINTMSG  endp

;unix_printchr proc near
;               ; 20/01/2013      
;               mov     AH,0Eh                  
;               mov     BX,07h             
;               int     10h                     ; BIOS Service func ( ah ) = 0Eh
;                                               ; Write char as TTY
;                                               ;AL-char BH-page BL-color
;               retn
;unix_printchr endp


unix_prompt proc near
		; 06/03/2013 
		; 05/03/2013 (default kernel name: unix)
		; 25/02/2013 BOOT1 version
		; 8/12/2012
		; Derived from
		; proc_dos_prompt procedure of TRDOS, 
		; MAINPROG.ASM (1/1/2012). 
		;
		; proc_dos_prompt (15/09/2011)
		;

	       ;push ds
	       ;pop  es 
unix_prompt_1:
		mov     si, offset Boot_Msg
		call    unix_printmsg
unix_prompt_2:     
		mov     ah, 03h
		;mov    bx, 07h                  
		int     10h
		mov     byte ptr [CursorColumn],dl
		; 
unix_prompt_14: ; 07/03/2013 
		; automatic kernel loading timer
		;
		cmp     byte ptr [def_kernel], bh ; 0
		ja      short unix_prompt_3
unix_prompt_15:                
		hlt     ; halt cpu until external interrupt
		
		mov     ah, 1h ; Get keystroke status
		int     16h
		; ZF = 0 if key pressed
		jnz     short unix_prompt_16
		
		mov     cx, 40h
		mov     ax, ds
		mov     bx, 6Ch ; mov si, 6Ch
		mov     es, cx
		mov     cx, word ptr ES:[BX] ; ES:[SI]
		mov     es, ax

		cmp     cx, word ptr [waiting_count]
		jb      short unix_prompt_15 
		
		dec     byte ptr [def_kernel] ; FFh

		mov     si, offset UNIX_CRLF                
		call    unix_printmsg
		
		mov     si, offset CommandBuffer
		mov     di, si
		jmp     short unix_prompt_17
unix_prompt_16:
		inc     byte ptr [def_kernel]
unix_prompt_3:
		mov     si, offset CommandBuffer
		call    proc_rw_char
		mov     di, si
		xor     bx, bx
		xor     cx, cx
unix_prompt_4:
		mov     al, byte ptr [SI][BX]
		inc     bl 
		cmp     al, 20h
		ja      short unix_prompt_6
		jb      short unix_prompt_10
		cmp     bl, 74 ; 75 ?
		jb      short unix_prompt_4
unix_prompt_11:
		mov     bx,07h 
		mov     al,0Dh
		mov     ah,0Eh
		int     10h
		mov     al,0Ah
		int     10h
		jmp     unix_prompt_1 ; loop
unix_prompt_5:
		mov     al, byte ptr [SI][BX]
		inc     bl
		cmp     al,20h
		jna     short unix_prompt_7
unix_prompt_6:
		stosb   
		inc     cl
		cmp     bl, 74 ; 75 ?
		jb      short unix_prompt_5
unix_prompt_7:
		xor     al, al ; 0
unix_prompt_8:
		mov     byte ptr [DI], al
		inc     di
		cmp     bl, 74 ; 75 ?
		jnb     short unix_prompt_9
		mov     al, byte ptr [SI][BX]
		inc     bl
		cmp     al, 20h
		jnb     short unix_prompt_8
		mov     byte ptr [DI], 0
unix_prompt_9:
		call    command_interpreter

		xor     al, al ; 07/03/2013

		cmp     byte ptr [unix_reboot], al ; 0
		ja      short unix_prompt_13 ; 06/03/2013
unix_prompt_12:
		mov     cx, 74 ; 75 ?
		mov     di, offset CommandBuffer
		xor     al,al
		rep     stosb
		jmp     short unix_prompt_11 ; 06/03/2013
unix_prompt_10:
		; 05/03/2013
		xor     al, al
		cmp     byte ptr [def_kernel], al ; 0
		ja      short unix_prompt_11 ; 06/03/2013
		;mov     di, offset CommandBuffer
unix_prompt_17: ; 07/03/2013 (timer code jumps here)
		mov     ax, 'nu'
		stosw
		mov     ax, 'xi'
		stosw
		xor     al, al  
		stosb
		;mov    cl, 4
		;jmp    short unix_prompt_9
		call    loc_load_kernel ; jump/go to kernel
		jmp     short unix_prompt_12 ; error return only 

unix_prompt_13: ; 06/03/2013
		retn

unix_prompt endp


proc_rw_char proc near
	       ; 8/12/2012 (modification for UNIXCOPY.ASM)
	       ; OUTPUT -> DS:SI = Entered String (ASCIIZ)
	       ;
read_next_char:
	       xor     ah,ah
	       int     16h
	       and     al,al
	       jz      short loc_arrow    
	       cmp     al,0E0h          
	       je      short loc_arrow
	       cmp     al,08h
	       jne     short char_return
loc_back:
	       mov     bl,7
	       mov     ah,3
	       int     10h
	       cmp     dl,byte ptr [CursorColumn]
	       ja      short prev_column
loc_beep:
	       mov     ah, 0Eh
	       mov     al, 7
	       int     10h
	       jmp     short read_next_char
prev_column:
	       dec     dl
set_cursor_pos:
	       mov     ah,02h
	       int     10h
	       mov     bl, dl
	       sub     bl,byte ptr [CursorColumn] 
	       mov     cx,1
	       mov     ah,09h
	       mov     al,20h
	       mov     byte ptr [SI][BX],al
loc_write_it:
	       mov     bl,7
	       int     10h
	       mov     dx,word ptr [CursorColumn]
	       jmp     short read_next_char
loc_arrow:    
	       cmp     AH,4Bh
	       je      short loc_back
	       cmp     AH,53h
	       je      short loc_back
	       jmp     short read_next_char
char_return:
	       mov     bl,7
	       mov     ah,3
	       int     10h

	       mov     ah, dl           
	       sub     ah,byte ptr [CursorColumn] 
	       cmp     al,20h
	       jb      short loc_escape
	       cmp     ah, 72 ; limit
	       ja      short loc_beep

	       mov     bl, ah
	       xor     ah, ah
	       mov     word ptr [SI][BX],ax
	       mov     ah, 0Eh
	       mov     bl, 7
	       int     10h
	       jmp     short read_next_char
pass_escape:
	       cmp     al,0Dh
	       jne     short read_next_char
	       mov     ah, 0Eh          
	       mov     bl,7
	       int     10h
	       mov     al,0Ah
	       int     10h
	       retn
loc_escape:
	       cmp     al,1Bh
	       jne     short pass_escape
	       stc
	       retn

proc_rw_char endp


command_interpreter proc near
		; 06/03/2013 (loc_load_kernel)
		; 25/02/2013 BOOT1 version
		; 23/02/2013 ?/help
		; 17/02/2013 namei, inode, iget
		; 16/02/2013 fs, volume 
		; 21/01/2013 'ls -l'
		; 20/01/2013 ls (dir modifications)
		; 13/01/2013 chmod, chown, link
		; 07/01/2013 show tabspace (div) modif.
		; 06/01/2013 show
		; 06/01/2013 rm, mkdir, rmdir modifications
		; 05/01/2013 check file attributes
		; 30/12/2012
		; 24/12/2012 todos
		; 16/12/2012
		; 08/12/2012
		;
		lodsw
cl3:
		cmp cl, 3
		jb short cl2
		ja cl5
; DIR
loc_cmd_dir:    ; 05/01/2013 @b->@f, dir_print modifications
		cmp ax, 'id'
		jne loc_load_kernel  ; @f
		lodsb
		cmp al, 'r'
		jne loc_load_kernel  ; @f
		;lodsb
		;or al, al
		;jnz loc_load_kernel  ; @f
		mov byte ptr [ls_option], 0
		inc si
dir_getarg:     ; 30/12/2012
		lodsb
		cmp al, 20h
		je short dir_getarg
		jnb short dir_namei
ls_getarg3:
		xor ax, ax
		jmp short dir_print
dir_namei:      ; 30/12/2012
		dec si
		mov word ptr [u_namep], si
		call name_i
		jc short ci_error
		; ax = i-number
dir_print:
		call print_directory_list
		jnc short @f
ci_error:
		mov si, offset error_msg
		call unix_printmsg
@@:             
		retn
; 23/02/2013
cl1:
		cmp al, '?'
		jne loc_load_kernel  ; @b
		;cmp ah, 0
		;jne loc_load_kernel  ; @f

		mov si, offset Boot_Commands
		call UNIX_PRINTMSG
@@:             
		retn             
; 16/12/2012
cl2:
		cmp cl, 2
		jb short cl1 ; 23/02/2013
		; jb @b
; LS (DIR)      
loc_cmd_ls:     ; 20/01/2013
		cmp ax, 'sl'
		jne short loc_cmd_cd ; 25/02/2013
		;lodsb
		;or al, al
		;jnz short loc_load_kernel  ; @b
		mov byte ptr [ls_option], 1
		inc si
ls_getarg1:     ; 21/01/2013
		lodsb
		cmp al, 20h
		je short ls_getarg1
		jb short ls_getarg3
ls_getarg2:
		cmp al,'-'
		jne short dir_namei
		lodsb
		cmp al, 'l'
		jne short ls_getarg3
ls_getarg4:
		lodsb
		inc byte ptr [ls_option]
		cmp al, 20h
		je short dir_getarg
		jb short ls_getarg3
		dec byte ptr [ls_option]
		jmp short ls_getarg3
; CD (CHDIR)
loc_cmd_cd:
		cmp ax, 'dc'
		jne short loc_cmd_fs ; 25/02/2023
		;lodsb
		;or al, al
		;jnz short loc_load_kernel  ; @f
		inc si
ci_cd_getarg:
		mov word ptr [u_namep], si
		lodsb
		cmp al, 20h
		je short ci_cd_getarg
		jb short @f
		; dec si

		mov ax, word ptr [u_namep]
		mov word ptr [arg], ax

		call sys_chdir
		jc ci_error
		
		mov si, word ptr [arg]
		call update_cdir_string
@@:
		retn


; FS (Volume)  ; 16/02/2013   (File System / Volume Info)
loc_cmd_fs:     cmp ax, 'sf'
		jne loc_load_kernel  ; @b
		;lodsb
		;or al, al
		;jnz short loc_load_kernel  ; @b
fs_info_print:
		call print_volume_info
@@:
		retn
cl5:
		cmp cl, 5
		ja cl6
		jb cl4

; NAMEI         ; 17/02/2013, print i-number of file/directory
loc_cmd_namei:
		cmp ax, 'an'
		jne short loc_cmd_inode
		lodsw
		cmp ax, 'em'
		jne loc_load_kernel  ; @f
		lodsb   
		cmp al, 'i'     
		jne loc_load_kernel  ; @f
		;lodsb
		;or al, al
		;jnz short loc_load_kernel  ; @f
		inc si
namei_sf1:
		mov word ptr [u_namep], si
		lodsb
		cmp al, 20h
		je short namei_sf1
		jb short @f
namei_sf2:
		lodsb
		cmp al, 20h
		ja short namei_sf2
		dec si
		xor al, al
		mov byte ptr [SI], al
namei_fsf:
		call name_i
		jnc short namei_iget
namei_unix_stc: 
		cmp ah, 0FFh
		jb ci_error
		mov si, offset NotFound_msg
		call UNIX_PRINTMSG
@@:
		retn
namei_iget:
		call i_get
namei_print_inum:
		jc ci_error
		mov cx, ax
		mov si, offset msgINumber
		call UNIX_PRINTMSG              
		mov ax, cx
		mov cx, 3
		call print_decimal_number
		mov si, offset UNIX_CRLF
		call UNIX_PRINTMSG      
		retn

; INODE         ; 17/02/2013, print inode structure/details
loc_cmd_inode:
		cmp ax, 'ni'
		jne short loc_load_kernel  ; @b
		lodsw
		cmp ax, 'do'
		jne short loc_load_kernel  ; @b
		lodsb   
		cmp al, 'e'     
		jne short loc_load_kernel  ; @b
		;lodsb
		;or al, al
		;jnz short loc_load_kernel  ; @b
		inc si
inode_getarg1:
		mov bx, si
		lodsb
		cmp al, 20h
		je short inode_getarg1
		ja short inode_getarg2
		mov ax, word ptr [ii]
		jmp short @f
inode_getarg2:
		lodsb
		cmp al, 20h
		ja short inode_getarg2
		dec si
		xor ax, ax
		mov byte ptr [SI], al
		mov si, bx
@@:
		call show_inode
		jc ci_error
@@:             
		retn
cl4:
		;cmp cl, 4
		;jb cl3
; SHOW
loc_cmd_show:
		; 06/01/2013
		cmp ax, 'hs'
		jne short loc_load_kernel ; loc_cmd_unix ; 05/03/2013
		lodsw
		cmp ax, 'wo'
		jne short loc_load_kernel  ; @b
		;lodsb
		;or al, al
		;jnz short loc_load_kernel  ; @b
		inc si
show_uf1:
		mov word ptr [u_namep], si
		lodsb
		cmp al, 20h
		je short show_uf1
		jb short @f
show_uf2:
		lodsb
		cmp al, 20h
		ja short show_uf2
		xor al, al
		mov byte ptr [SI]-1, al
show_uf3:
		call show_file
		jc ci_error
@@:
		retn

; UNIX (default kernel name) ; 06/03/2013
;loc_cmd_unix:   
loc_load_kernel: ; 07/03/2013 
		; 06/03/2013
		mov word ptr [u_namep], offset CommandBuffer
		call load_kernel
		jnc short @f
		
		cmp byte ptr [def_kernel], 0FFh ; auto loading
		jb namei_unix_stc 
		
		; no error msg when it was auto kernel loading
		retn
@@:
		mov si, offset UNIX_CRLF
		call unix_printmsg
	       
		; 14/07/2013
		mov dl, byte ptr [PhysicalDriveNumber]
		xor dh, dh

		mov ax, kernel_loading_segment ; 1000h 
		mov ds, ax
		mov es, ax
		cli
		mov ss, ax
		mov sp, 32766 ; 09/07/2013 
					; FFFEh 
		sti

		mov bx, offset EndOfFile ; Relocated BS buffer address

		mov bp, sp
		mov cx, cs ; 07/03/2013 (CX = Buffer segment) 
		
	     ; MASM.EXE don't accept
	     ; jmp 1000h:0000h
	     ; for OP Code: EA00000010
		db 0EAh
		dw 0
		dw kernel_loading_segment  ; 09/07/2013 
	
cl6: ; 16/02/2013       
		cmp cl, 6
		ja short cl8 

; REBOOT        ; 25/02/201
loc_cmd_reboot:
		cmp ax, 'er'
		jne short loc_load_kernel  ; @b
		lodsw
		cmp ax, 'ob'
		jne short loc_load_kernel  ; @b
		lodsw
		cmp ax, 'to'
		jne short loc_load_kernel  ; @b
		;lodsb
		;or al, al
		;jnz short loc_load_kernel  ; @f

		mov byte ptr [unix_reboot], 1
@@:
		retn
cl8:
		cmp cl, 8
		ja short @b  ; bad command or file name
		jb short loc_load_kernel  ; @b
; BOOTFILE
loc_cmd_bootfile:
		cmp ax, 'ob'
		jne short loc_load_kernel  ; @b
		lodsw
		cmp ax, 'to'
		jne short loc_load_kernel  ; @b
		lodsw
		cmp ax, 'if'
		jne short loc_load_kernel  ; @b
		lodsw   
		cmp ax, 'el'    
		jne short loc_load_kernel  ; @b
		;lodsb
		;or al, al
		;jnz short loc_load_kernel  ; @b

		mov si, word ptr [BSBuffer] ; 06/03/2013
		add si, bs_BF_inode_Number
		mov ax, word ptr [SI]
;               and ax, ax
;               jnz short @f
;ci_no_bootfile:                
;               mov si, offset msg_Startup_File_Not_Exists
;               call UNIX_PRINTMSG
;               retn
@@:
		call find_bfn
		jc  ci_error
ci_move_bfn_1:
		mov si, offset u_dirbuf + 2
		mov di, offset Boot_File_Name
		mov cx, 8
ci_move_bfn_2:
		lodsb
		and al, al
		jnz short @f
		mov byte ptr [DI], al ; 0
@@:
		stosb
		loop ci_move_bfn_2

		call proc_display_startupfile_info

		retn

command_interpreter endp


update_cdir_string proc near
	; 13/01/2013 bugfix
	; 10/12/2012
	; 09/12/2012
	; input -> SI= chdir argument
ucds_0:
	mov bx, offset unix_cdir
	inc bx ; 13/01/2013
	mov di, bx
	lodsb
	cmp al, '/'
	jne short @f
	xor dx, dx
	mov word ptr [CDirOffset], dx
	jmp short ucds_6
@@:
	mov dx, word ptr [CDirOffset]
	; 13/01/2013
	or dx, dx
	jz short @f
	add di, dx
	mov byte ptr [DI], '/'
	inc di
	;
	jmp short  @f
ucds_8:
	inc di
ucds_6:
	lodsb
	cmp al, '/'
	je short ucds_6
@@:
	or al, al
	jz short ucds_5
	cmp al, '.'
	jne short ucds_3
	lodsb
	cmp al, '.'
	je short ucds_2 ; dotdot
ucds_1: ;dot
	cmp al, '/'
	je short ucds_6
	or al, al
	jz short ucds_5
	mov ah, '.'
	xchg ah, al
	stosw
	jmp short ucds_6
ucds_2: ; dotdot
	cmp di, bx
	ja short @f
	xor dx, dx
	mov byte ptr [DI], dl ; 0
	jmp short ucds_7
@@: ; 13/01/2013
	dec di
@@: ; move back
	dec di ; 13/01/2013
	mov al, byte ptr [DI]
	cmp al, '/'
	jne short @b ; 13/01/2013
	jmp short ucds_8
ucds_4:
	stosb
	jmp short ucds_6
ucds_3:
	stosb
	lodsb
	cmp al, '/'
	je short ucds_4
	and al, al
	jnz short ucds_3
ucds_5: ; 13/01/2013
	cmp di, bx
	jna short ucds_9
	dec di
	cmp byte ptr [DI], '/'
	je short ucds_9
	inc di
ucds_9:
	; 13/01/2013
	mov byte ptr [DI], al ; 0
	mov dx, di
	sub dx, bx
ucds_7:
	mov word ptr [CDirOffset], dx
	
	retn

update_cdir_string  endp


print_directory_list proc near
	; 23/02/2013 long list printing (list_count)
	; 03/02/2013
	; 22/01/2013 ls -l command feature 
	; 21/01/2013 dir/ls options
	; 20/01/2013 directory sign ("/")
	; 30/12/2012
	or ax, ax ; i-number of directory       
	jnz short @f
	
	; 09/12/2012
pdl_0:  
	mov ax, word ptr [u_cdir]
@@:
	call i_get
	jc short @f ; 20/01/2013 ; jc short pdl_9

	test word ptr [inode_flgs], 4000h ; directory i-node ?
	jnz short pdl_2
pdl_1:
	mov ah, 0FFh ; error number
	stc
@@: ; 20/01/2013
       ;jmp short pdl_9
	retn
pdl_2:
	; 25/02/2013
	mov si, offset unix_cdrv ; print current directory
	call unix_printmsg
	;
	;mov ax, word ptr [inode_size]
	;mov word ptr [u_dirp], ax ; put size of directory in u.dirp
	
	;xor ax, ax
	xor ah, ah
	mov word ptr [u_off], ax ; u.off is file offset used by user
	;mov word ptr [u_fofp], offset u.off
			       ; u.fofp is a pointer to the offset portion 
			       ; of fsp entry
	mov byte ptr [list_count], al ; 0 ; 23/02/2013 
pdl_3:
	mov word ptr [u_base], offset u_dirbuf
				  ; u.dirbuf holds a file name copied from
				  ; a directory 
	mov word ptr [u_count], 10 
			  ; u.dirbuff holds a file name copied from
				  ; a directory 
	mov ax, word ptr [ii]
		
	call read_i ; read 10 bytes of file with i-number (R1)
		   ; i.e. read a directory entry
	jc short @b ; jc short pdl_9
	
	mov cx, word ptr [u_nread]
	or cx, cx
	jna short pdl_1 ; gives error return 
	
	mov bx, word ptr [u_dirbuf]
	and bx, bx       
	jz pdl_8
pdl_4:
	mov si, offset u_dirbuf + 2 ; r3, points to file name of directory entry
	mov cx, 8 ; max. file name length
	mov di, offset DirFileName + 1 ; boot_File_Name
pdl_5:
	lodsb  ; mov al, byte ptr [SI], inc si
	or al, al
	jz short pdl_6 ; 3f. If char is nul, then the last char in string has
			 ; been compared
	stosb  ; mov byte ptr [DI], al, inc di 
	loop pdl_5
pdl_6: 
	; 21/01/2013
	mov si, offset UNIX_CRLF
	call unix_printmsg
	cmp byte ptr [ls_option], 1
	je short pdl_7
	;mov al, 0
	mov byte ptr [DI], al
	jb short pdl_13
pdl_7:
	; 20/01/2013
	push di
	mov ax, word ptr [ii]
	mov word ptr [pdir], ax
	mov ax, word ptr [u_dirbuf]
	call i_get
	pop di
	jc pdl_9

	; 22/01/2012
	cmp byte ptr [ls_option], 1
	jna short @f
	
pdl_11: ; 21/01/2013 ; Inode number
	mov ax, word ptr [u_dirbuf]
	mov cx, 3 ; 03/02/2013
	call print_decimal_number
	jmp short pdl_10
@@:
	mov ax, word ptr [inode_flgs]
	test ah, 40h ; 'directory' flag
	jz short pdl_10

	mov si, offset u_dirbuf + 2
	lodsb
@@:
	cmp al, '.' ; '.'
	jne short @f
	lodsb
	or al, al
	jz short pdl_10
	jmp short @b
@@:     
	mov  al, '/'
	mov byte ptr [DI], al
	inc di
pdl_10:
	; 21/03/2013
	xor al, al
	mov byte ptr [DI], al
pdl_13: ; File/Directory name
	inc byte ptr [list_count] ; 23/02/2013
	mov si, offset DirFileName
	call unix_printmsg

	; 22/01/2013
	cmp byte ptr [ls_option], 1
	je pdl_12  ; 03/02/2013 short -> near
	jb pdl_8 ; 23/02/2013 

	; 03/02/2013
@@:     ; Owner (uid)
	;xor bh, bh ; mov bh, 0
	mov ah, 03h ; get cursor position and size.
	int 10h
	cmp dl, 13
	jnb short @f
	mov al, 20h
	call putc
	jmp short @b
@@:
	xor ah, ah
	mov al, byte ptr [inode_uid]
	mov cx, 3
	call print_decimal_number       
@@:
	mov al, 20h
	call putc
	
	mov al, 20h
	call putc

@@:     ; Flags/Attributes
	mov dx, word ptr [inode_flgs]
	mov cl, '-'
	shl dh, 1
	shl dh, 1
	jnc short @f
	add al, 'd'-'-'
@@:
	add al, cl
	call putc
	shl dl, 1
	shl dl, 1
	shl dl, 1
	shl dl, 1
	jnc short @f
	add al, 'x'-'-'
@@:
	add al, cl
	call putc
	shl dl, 1
	jnc short @f
	add al, 'r'-'-'
@@:
	add al, cl
	call putc       
	shl dl, 1
	jnc short @f
	add al, 'w'-'-'
@@:
	add al, cl
	call putc                       
	shl dl, 1
	jnc short @f
	add al, 'r'-'-'
@@:
	add al, '-'
	call putc       
	shl dl, 1
	jnc short @f
	add al, 'w'-'-'
@@:
	add al, cl
	call putc

	mov al, 20h
	call putc

@@: ; File Size ; 03/02/2013
	mov ax, word ptr [inode_size]
	;mov cx, 5
	mov cl, 5
	call print_decimal_number       
@@:
	mov al, 20h
	call putc

	mov al, 20h
	call putc

@@: ; 03/02/2013 ; File creation date & time    
	;mov ax, word ptr [inode_ctim]
	;mov dx, word ptr [inode_ctim]+2
	
	; 23/02/2013 ; File last modification date & time       
	mov ax, word ptr [inode_mtim]
	mov dx, word ptr [inode_mtim]+2
	
	call convert_from_epoch
	; cx = day

	mov ax, cx ; word ptr [day]
	mov si, offset dec_num
	mov bx, si
	add bx, 2       
	; mov cx, 2
	mov cl, 2
	call proc_bin_to_decimal
	mov byte ptr [BX], '/'
	mov si, bx
	inc si
	mov ax, word ptr [month]
	; mov cx, 2
	mov cl, 2
	call proc_bin_to_decimal
	add bx, 3
	mov byte ptr [BX], '/'
	mov si, bx
	inc si
	mov ax, word ptr [year]
	;mov cx, 4
	mov cl, 4
	call proc_bin_to_decimal

	mov si, offset dec_num
	call unix_printmsg

	mov al, 20h
	call putc

	mov si, offset dec_num
	mov bx, si
	mov ax, word ptr [hour]
	; mov cx, 2
	mov cl, 2
	call proc_bin_to_decimal
	add bx, 2
	mov byte ptr [BX],':'

	mov si, bx
	inc si
	mov ax, word ptr [minute]
	; mov cx, 2
	mov cl, 2
	call proc_bin_to_decimal
	add bx, 3
	;mov byte ptr [BX], ':'
	;mov si, bx
	;inc si
	;mov ax, word ptr [second]
	;;mov cx, 2
	;mov cl, 2
	;call proc_bin_to_decimal
	;add bx,
	xor al, al
	mov byte ptr [BX], al 

	mov si, offset dec_num
	call unix_printmsg
pdl_12:
	mov ax, word ptr [pdir]
	call i_get
	jc pdl_9
pdl_8:
	; 30/12/2012
	mov ax, word ptr [u_off]
	cmp ax, word ptr [inode_size]
	jnb short @f ; 22/02/2013 ; jb pdl_3
	; 23/02/2013
	cmp byte ptr [list_count], 21
	jb pdl_3
	xor ah, ah
	mov byte ptr [list_count], ah ; 0
	int 16h
	cmp al, 1Bh  ; ESC key
	jne pdl_3
@@:
	mov si, offset UNIX_CRLF
	call unix_printmsg
pdl_9:
	retn

putc:  ; 22/01/2013
	mov ah, 0Eh
	;mov bx, 07h
	int 10h
	xor al, al

	retn

print_directory_list endp


sys_chdir proc near
	; 09/12/2012 unixcopy.asm
	;       Retro UNIX v1 FS file import/export version
	;             of syschdir function  
	; Derived from (original) UNIX v1 source code
	; PRELIMINARY release of Unix Implementation Document, 
	; 20/6/1972
	;
	; RETRO UNIX v1 FS
	; syschdir:
	; makes the directory specified in the argument 
	; the current directory

	; mov word ptr [u_namep], si

syschdir_0:
	call name_i
	jc short syschdir_5

syschdir_1:
	call i_get
	jc short syschdir_5
syschdir_2:
	test word ptr [inode_flgs], 4000h ; directory i-node ?
	jnz short syschdir_4
syschdir_3:
	mov ah, 0FFh
	stc
	retn    
syschdir_4:     
	mov word ptr [u_cdir], ax
	; mov dx, word ptr [cdev]
	; mov word ptr [u_cdev], dx

syschdir_5:
	retn

sys_chdir endp


show_file proc near
	; 05/03/2013
	; 07/01/2013
	; 06/01/2013
	; derived from TRDOS command interpreter file (CMDINTR.ASM)
	; 'show' procedure (13/09/2011)

	call name_i
	jc short suf_4

	call i_get
	jc short suf_4

	test word ptr [inode_flgs], 4000h  ; Directory
	jnz short suf_4
	
	mov si, offset UNIX_CRLF
	call UNIX_PRINTMSG

	mov ax, word ptr [inode_size]

	mov dx, 512
	cmp ax, dx
	jna short suf_1

	mov ax, dx
suf_1:
	xor dx, dx 
	mov word ptr [u_off], dx
	mov cx, 22
suf_2:                
	push cx 
	mov word ptr [u_count], ax
	mov ax, word ptr [FILEBUFFER]
	mov word ptr [u_base], ax
	mov ax, word ptr [ii] ; word ptr [u_dirbuf]
	call read_i
	pop cx
	jc short suf_4

	mov di, word ptr [u_nread]

	or di, di
	jz short suf_4

	mov si, word ptr [FILEBUFFER]

	jmp short suf_6
suf_3:
	and cx, cx
	jnz short suf_6
	xor ah, ah
	int 16h
	cmp al, 1Bh ; ESCAPE Key
	jne short suf_5
suf_4:
	mov si, offset UNIX_CRLF
	call UNIX_PRINTMSG

	retn
suf_5:
	mov cx, 20
suf_6:
	xor bh, bh ; mov bh, 0
	mov bl, 7

	lodsb
	cmp al, 0Dh ; ENTER/RETURN Char
	jne short suf_7
	dec cx
	jmp short suf_8 
suf_7:
	cmp al, 09h ; TAB Space Char
	je short suf_10
suf_8:
	mov ah, 0Eh
	;xor bh, bh ; mov bh, 0
	;mov bl, 7
	int 10h
suf_9:
	dec di
	jnz short suf_3
	mov ax, word ptr [u_nread]
	jmp short suf_2
suf_10:
	push cx
	;xor bh, bh ; mov bh, 0
	mov ah, 03h ; get cursor position and size.
	int 10h
	mov al, dl
	mov cx, 8
;suf_11a:
;       cmp al, cl
;       jb short suf_11b
;       sub al, cl
;       jmp short suf_11a
;suf_11b:
;        sub cl, al
suf_11:
	; 07/01/2013
	xor ah, ah
	div cl
	sub cl, ah      
	;
	mov al, 20h
	mov ah, 0Eh 
	;mov bl, 7 ; char color attribute       
suf_12:
	int 10h
	loop suf_12
	pop cx
	jmp short suf_9 

show_file endp


name_i proc near
	; 05/01/2013
	; 09/12/2012 unixcopy.asm
	;       Retro UNIX v1 FS file import/export version
	; 31/10/2012
	; 14/10/2012
	; 07/10/2012
	; Derived from (original) UNIX v1 source code
	; PRELIMINARY release of Unix Implementation Document, 
	; 20/6/1972
	;
	; RETRO UNIX v1 FS
	;
	; return i-number of file (in AX)
	;
	; input:
	; u_namep = pointer to file path name
	; u_cdir = i-number of users directory
	; ;;u_cdev = device number
	; output:
	; cf= 0 -> no error, i-number in AX (R1)
	; cf= 1 -> error code in AX
	;       

	mov si, word ptr [u_namep]

	cmp byte ptr [SI], '/' ; is first char in file name a /
	jne short @f
	mov ax, ROOT_DIR_INODE_NUMBER ; 41
		; Put i-number of root directory in R1
	; xor dx, dx
	inc si  ; go to next char
	mov word ptr [u_namep], si
	jmp short namei_0
@@:
	;mov dx, word ptr [u_cdev]
	mov ax, word ptr [u_cdir] 
		; put i-number of current directory in R1
namei_0:
	;mov word ptr [cdev], dx 
		; device file for users directory into cdev
; 1
	cmp byte ptr [SI], 0 ; is the character in file name a nul
	jna short namei_7 ;nig

namei_1: ; 1            
	; get i-node with i-number r1
	call i_get
	jc short namei_7

	test word ptr [inode_flgs], 4000h ; directory i-node ?
	;jz short namei_6 ; got an error
	jnz short @f
;nib:
namei_6:
	mov ah, 0FFh ; Error code
	stc
;nig:
namei_7:
	retn
@@:
	mov ax, word ptr [inode_size]
	mov word ptr [u_dirp], ax ; put size of directory in u.dirp
	
	xor ax, ax 
	mov word ptr [u_off], ax ; u.off is file offset used by user
	;mov word ptr [u_fofp], offset u.off
			       ; u.fofp is a pointer to the offset portion 
			       ; of fsp entry
namei_2: ; 2
	mov word ptr [u_base], offset u_dirbuf
				  ; u.dirbuf holds a file name copied from
				  ; a directory 
	mov word ptr [u_count], 10      
	
	mov ax, word ptr [ii]
		
	call read_i ; read 10 bytes of file with i-number (R1)
		   ; i.e. read a directory entry
	jc short namei_7
	
	mov cx, word ptr [u_nread]

	or cx, cx
	jna short namei_6 ; nib ; gives error return 
	
	mov bx, word ptr [u_dirbuf]
	and bx, bx       
	jnz short namei_3 ; 3f. branch when active directory entry
			  ; (i-node word in entry non zero)     
	mov ax, word ptr [u_off]
	sub ax, 10
	mov word ptr [u_dirp], ax
	jmp short namei_2 ; 2b

namei_3: ; 3
	mov si, word ptr [u_namep] ; r2, u.namep points into a file name string
	mov di, offset u_dirbuf + 2 ; r3, points to file name of directory entry
	mov dx, offset u_dirbuf + 10
@@:     ; 3
	lodsb  ; mov al, byte ptr [SI], inc si   (al = r4)
	or al, al
	jz short namei_4 ; 3f. If char is nul, then the last char in string has
			 ; been compared
	cmp al, "/"      ; is char a "/"
	je short namei_4 ; 3f
	cmp di,dx ; offset u_dirbuf + 10 ; r3, 
				     ; have i checked all 8 bytes of file name
	je short @b ; 3b
	scasb                 ; cmpb (r3)+, r4   (DI=R3, AL=R4)
			      ; compare char in u.namep string to file name char
			      ; read from
	je short @b ; directory; brach if chars match
	
	jmp short namei_2 ; 2b
			  ; File names do not match, go to next directory entry         
namei_4: ; 3
	cmp di, dx ; offset u_dirbuf + 10 ; r3, 
				     ; if equal all 8 bytes were matched
	je short namei_5 ; 3f

	mov ah, byte ptr [DI]
	;inc di  ; 05/01/2013
	and ah, ah  ; tstb (r3)+, bne 2b
	jnz short namei_2 ; 2b

namei_5: ; 3
	mov word ptr [u_namep], si ; r2
				; u.namep points to char following a "/" or nul
	;mov bx, word ptr [u_dirbuf] ; r1
	
	and al, al      ; r4. If r4=0 the end of file name reached,
			; if r4="/" then go to next directory
	mov ax, bx

	jnz namei_1 ; 1b

	retn

name_i  endp


read_i proc near
	; 06/03/2013 (kernel loading segment)
	; 05/03/2013
	; 14/10/2012
	; Boot sector version of "readi" procedure
	; Derived from (original) UNIX v1 source code
	; PRELIMINARY release of Unix Implementation Document, 
	; 20/6/1972
	;;AX (R1) = i-number 
	; RETRO UNIX v1 FS
	; Boot sector version
	;
	; read from an i-node
	;

	xor dx, dx ; 0
	mov word ptr [u_nread], dx ; accumulated number of bytes transmitted
	cmp word ptr [u_count], dx ; is number of byte to read greater than 0
	jna short read_inode_retn

read_inode_1:
	; AX = I-Number
	push ax
	call i_get ; get i-node into i-node section of core
	mov dx, word ptr [inode_size] ; file size in bytes in r2 (DX)
	sub dx, word ptr [u_off] ; subtract file offset
	jna short read_inode_3
	cmp dx, word ptr [u_count] 
			; are enough bytes left in file to carry out read
	jnb short read_inode_2
	mov word ptr [u_count], dx

read_inode_2:
	call m_get  ; returns physical block number of block in file 
		   ; where offset points
	; AX = Physical block number
	call dsk_rd ; read in block, BX points to 1st word of data in
		   ; buffer
	jc short read_inode_3

readinode_sioreg:
	mov si, word ptr [u_off] ; R2
	mov cx, si ; cx = R3, si = R2
	or cx, 0FE00h ; set bits 9...15 of file offset in R3
	and si, 1FFh ; calculate file offset mod 512
	add si, bx ; word ptr [DISKBUFFER] ; si now points to 1st byte in buffer
		   ; where data is to be placed
	mov di, word ptr [u_base] ; R1
	neg cx ; 512 - file offset(mod512) in R3 (cx)
	cmp cx, word ptr [u_count]
	jna short @f ; 2f

	mov cx, word ptr [u_count]
@@:
	add word ptr [u_nread], cx ; r3 + number of bytes
			; xmitted during write is put into
			; u_nread
	sub word ptr [u_count], cx
	add word ptr [u_base], cx ; points to 1st of remaining
			; data bytes
	add word ptr [u_off], cx ; new file offset = number 
			; of bytes done + old file offset

; end of readinode_sioreg

	; DI = file (user data) offset
	; SI = sector (I/O) buffer offset
	; CX = byte count 

	; 06/03/2013
	mov ax, word ptr [EXTRA_SEGMENT] ; kernel loading segment or CS/DS
	mov es, ax

	rep movsb

	mov ax, ds ; 06/03/2013
	mov es, ax              

	pop ax

	cmp word ptr [u_count], 0
	ja short read_inode_1

	retn

read_inode_3:   
	pop ax ; i-number

read_inode_retn:
	retn 

read_i  endp


i_get   proc near
	; 02/03/2013
	; 24/02/2013 BOOT1 version
	; 18/11/2012 unix boot file configuration version
	; of "iget" procedure.
	; 16/9/2012
	; 14/7/2012
	; Derived from (original) UNIX v1 source code
	; PRELIMINARY release of Unix Implementation Document, 
	; 20/6/1972
	;; AX=R1 
	; RETRO UNIX v1 FS
	;; return => if cf=1 error number in [Error]  

	cmp ax, word ptr [ii] ; AX (R1) = i-number of current file
	je short iget_4
iget_1:
	; 24/02/2013
	;mov dl, byte ptr [imod]
	;and dl, dl ; has i-node of current file been modified ?        
	;jz short iget_2
	;xor dl, dl ; mov al, 0
	;mov byte ptr [imod], dl 
	;push ax
	;mov ax, word ptr [ii]  
	;inc dl ; mov dl, 1
	;; dl = 1 = write
	;call i_calc
	;pop dx
	;jc short iget_4 
	;mov ax, dx
iget_2:
	and ax, ax
	jz short iget_3
	mov word ptr [ii], ax
	;xor dl, dl ; 02/03/2013                
	; dl = 0 = read
	call i_calc
iget_3:
	mov ax, word ptr [ii]
iget_4:
	retn

i_get   endp


i_calc  proc near
	; 05/03/2013
	; 24/02/2013 BOOT1 version
	; 18/11/2012 unix boot file configuration version
	; of "icalc" procedure.
	; 17/8/2012
	; 14/7/2012
	; Derived from (original) UNIX v1 source code
	; PRELIMINARY release of Unix Implementation Document, 
	; 20/6/1972
	;; AX=R1
	; 0 = read, 1 = write
	; RETRO UNIX v1 FS
	;
	; i-node is located in block (i+47)/16 and
	; begins 32*(i+47) mod 16 bytes from its start
	;; return => if cf=1 error number in [Error]

	;;; input -> dl = 0 -> read, 1 = Write

	;mov byte ptr [rw], dl

	add ax, 47 ; add 47 to inode number
	push ax ; R1 -> -(SP)
	shr ax, 1 ; divide by 16
	shr ax, 1
	shr ax, 1
	shr ax, 1
		  ; ax contains block number of block in which
		  ; inode exists
	call dsk_rd
	pop dx
	jc short icalc_2

icalc_1:
	and dx, 0Fh     ; (i+47) mod 16
	shl dx, 1
	shl dx, 1
	shl dx, 1
	shl dx, 1
	shl dx, 1 
		  ; DX = 32 * ((i+47) mod 16)   
		  ; DX (R5) points to first word in i-node i.

	mov di, offset inode
		; inode is address of first word of current inode
	mov cx, 16 ; CX = R3    

	mov si, word ptr [DISKBUFFER]

	add si, dx

	; copy new i-node into inode area of (core) memory
	rep movsw

icalc_2:
	retn

i_calc  endp


dsk_rd  proc near
	; 06/03/2013
	; 05/03/2013
	; 28/11/2012 BugFix 
	; 20/10/2012 (buff_s)
	; 14/10/2012
	; fd boot sector version of "dskrd" procedure
	; Derived from (original) UNIX v1 source code
	; PRELIMINARY release of Unix Implementation Document, 
	; 20/6/1972
	; RETRO UNIX v1 FS
	; floppy disk boot sector version
	;; return => if cf=1 error number in [Error]

	 ; ax = sector/block number

	 mov bx, word ptr [DISKBUFFER]

	 cmp ax, word ptr [buff_s] ; buffer sector
	 je short dsk_rd_3

	 mov si, ax

	 xor ch, ch
	 mov cl, 4 ; Retry count
dsk_rd_1:
	 push  cx
	 mov   dx, 18                  ; Sectors per track
	 div   dl                      
	 mov   cl, ah                  ; Sector (zero based)
	 inc   cl                      ; To make it 1 based
	 shr   al, 1                   ; Convert Track to Cylinder
	 adc   dh, 0                   ; Heads (0 or 1)

	 mov   dl, byte ptr [PhysicalDriveNumber] 
	 mov   ch, al

	 mov   ah, 2                   ; 2=read         
	 mov   al, 01h
	 int   13h                     ; BIOS Service func ( ah ) = 2
				       ; Read disk sectors
				       ; BIOS Service func ( ah ) = 3
				       ; Write disk sectors
				       ;AL-sec num CH-cyl CL-sec
				       ; DH-head DL-drive ES:BX-buffer
				       ;CF-flag AH-stat AL-sec read
	 pop   cx
	 jnc   short dsk_rd_2
	 loop  dsk_rd_1
	 retn ; 06/03/2013
dsk_rd_2:
	 mov word ptr [buff_s], si 
dsk_rd_3:         
	 retn

dsk_rd  endp


m_get   proc near
	; 05/03/2013
	; 03/03/2013
	; 01/03/2013
	; 24/02/2013 BOOT1 version
	; 18/11/2012
	; 14/11/2012 unix boot file configuration version
	; of "mget" procedure
	; 31/10/2012
	; 20/10/2012
	; 19/8/2012
	; 13/8/2012
	; 27/7/2012
	; 21/7/2012
	; Derived from (original) UNIX v1 source code
	; PRELIMINARY release of Unix Implementation Document, 
	; 20/6/1972
	;; return -> AX=R1
	; RETRO UNIX v1 FS
	; initialization/format version
	; cf -> 1 = error (no free block)

	 ;; contents of bx, cx, dx will be destroyed 
mget_0:
	mov bl, byte ptr [u_off]+1
	xor bh, bh
	; BX = R2
	test word ptr [inode_flgs], 4096 ; 1000h
				     ; is this a large or small file
	jnz short mget_4 ; 4f ; large file

	test bl, 0F0h ; !0Fh  ; error if BX (R2) >= 16                    
	jnz short mget_2 ; 28/02/2013

	and bl, 0Eh  ; clear all bits but bits 1,2,3
	mov ax, word ptr inode_dskp[BX] ; AX = R1, physical block number
mget_3: 
	; 24/02/2013
	cmp ax, 1

mget_1: ; 2
	retn 

mget_4:  ; 4 ; large file
	; 05/03/2013
	and bl, 0FEh 
	push bx
	; 01/03/2013 Max. possible BX (offset) value is 127 (65535/512)
	;            for this file system (offset 128 to 255 not in use)

	; There is always 1 indirect block for this file system
	mov ax, word ptr [inode_dskp] ; inode_dskp[0]

	or ax, ax
	jnz short mget_5
	; 28/02/2013
mget_2: 
	stc
mget_7:
	pop bx
	retn
	
mget_5: ;2
	; ax = R1, block number
	call dsk_rd ; read indirect block
	jc short mget_7
mget_6:
	pop ax ; R2, get offset
	add bx, ax ; first word of indirect block
	mov ax, word ptr [BX] ; put physical block no of block
			      ; in file sought in R1 (AX)
	jmp short mget_3 ; 24/02/2013

m_get endp


convert_from_epoch proc near
	; 30/11/2012
	; Derived from DALLAS Semiconductor
	; Application Note 31 (DS1602/DS1603)
	; 6 May 1998
	;
	; INPUT:
	; DX:AX = Unix (Epoch) Time
	mov cx, 60
	call proc_div32
	;mov word ptr [imin], ax   ; whole minutes
	;mov word ptr [imin]+2, dx ; since 1/1/1970
	mov word ptr [second], bx  ; leftover seconds
	; mov cx, 60
	call proc_div32
	;mov word ptr [ihrs], ax   ; whole hours
	;mov word ptr [ihrs]+2, dx ; since 1/1/1970
	mov word ptr [minute], bx  ; leftover minutes
	; mov cx, 24
	mov cl, 24
	call proc_div32
	;mov word ptr [iday], ax  ; whole hours
				  ; since 1/1/1970
	; mov word ptr [iday]+2, dx ; DX = 0
	mov word ptr [hour], bx   ; leftover hours
	add ax, 365+366           ; whole day since
				  ; 1/1/1968    
	; adc dx, 0               ;  DX = 0
	; mov word ptr [iday], ax
	push ax
	mov cx, (4*365)+1         ; 4 years = 1461 days
	call proc_div32
	pop cx
	;mov word ptr [lday], ax  ; count of quadyrs (4 years)
	push bx
	;mov word ptr [qday], bx  ;  days since quadyr began
	cmp bx, 31 + 29           ; if past feb 29 then
	cmc                       ; add this quadyr's leap day
	adc ax, 0                 ; to # of qadyrs (leap days)
	;mov word ptr [lday], ax  ; since 1968                    
	;mov cx, word ptr [iday]
	xchg cx, ax               ; CX = lday, AX = iday                  
	sub ax, cx                ; iday - lday
	mov cx, 365
	;xor dx, dx               ; DX  = 0
	; AX = iday-lday, DX = 0
	call proc_div32
	;mov word ptr [iyrs], ax   ; whole years since 1968
	; jday = iday - (iyrs*365) - lday
	;mov word ptr [jday], bx  ; days since 1/1 of current year
	add ax, 1968              ; compute year
	mov word ptr [year], ax
	mov dx, ax              
	;mov ax, word ptr [qday]
	pop ax
	cmp ax, 365               ; if qday <= 365 and qday >= 60       
	ja short @f               ; jday = jday +1
	cmp ax, 60                ; if past 2/29 and leap year then
	cmc                       ; add a leap day to the # of whole
	adc bx, 0                 ; days since 1/1 of current year
@@:                     
	;mov word ptr [jday], bx
	mov cx, 12                ; estimate month
	xchg cx, bx               ; CX = jday, BX = month       
	mov ax, 366               ; mday, max. days since 1/1 is 365
	and dx, 11b               ; year mod 4  (and dx, 3) 
@@:     ; Month calculation       ; 0 to 11  (11 to 0)  
	cmp cx, ax                ; mday = # of days passed from 1/1
	jnb short @f
	dec bx                    ; month = month - 1
	shl bx, 1 
	mov ax, word ptr DMonth[BX] ; # elapsed days at 1st of month
	shr bx, 1                 ; bx = month - 1 (0 to 11)
	cmp bx, 1                 ; if month > 2 and year mod 4  = 0    
	jna short @b              ; then mday = mday + 1
	or dl, dl                 ; if past 2/29 and leap year then
	jnz short @b              ; add leap day (to mday)
	inc ax                    ; mday = mday + 1
	jmp short @b
@@:
	inc bx                    ; -> bx = month, 1 to 12
	mov word ptr [month], bx
	sub cx, ax                ; day = jday - mday + 1       
	inc cx                    
	mov word ptr [day], cx
	
	; ax, bx, cx, dx is changed at return
	; output ->
	; [year], [month], [day], [hour], [minute], [second]
	; 

	retn

convert_from_epoch endp


proc_mul32 proc near

    ; push cx

      mov cx, bx
      mov bx, dx

      mul cx

      xchg ax, bx

      push dx

      mul cx 

      pop cx 

      add ax, cx 
      adc dx, 0

      xchg bx, ax
      xchg dx, bx

    ; pop cx

      retn

proc_mul32 endp


proc_div32 proc near
	; 1999
	; (Rx_Dos_Div32) 32 bit divide procedure 
	; by Erdogan Tan
	; Input -> DX_AX = 32 bit dividend
	;          CX = 16 bit divisor
	; output -> DX_AX = 32 bit quotient
	;          BX = 16 bit remainder
	mov  bx, dx
	xchg ax, bx
	xor  dx, dx
	div  cx         ; at first, divide DX
	xchg ax, bx     ; remainder is in DX
			; now, BX has quotient
			; save remainder
	div  cx         ; so, DX_AX divided and
			; AX has quotient
			; DX has remainder
	xchg dx, bx     ; finally, BX has remainder

	retn

proc_div32 endp


find_bfn proc near
	; 26/11/2012
	; 25/11/2012
	;
	; find boot file name by i-number (ax)
	;
	; cf -> 1 means error, ax = 0 -> not found

	mov word ptr [uf_i_number], ax
	push si

	mov ax, ROOT_DIR_INODE_NUMBER ; 41
	call i_get
	jc short loc_find_bfn_retn

	;test word ptr [inode_flgs], 4000h ; directory i-node ?
	;jnz short @f

	;mov ah, 0FFh ; error number
	;stc
	;jmp short loc_find_bfn_retn
;;@@:
	xor ax, ax 
	mov word ptr [u_off], ax ; u_off is file offset used by user

loc_find_bfn_1:
	mov word ptr [u_base], offset u_dirbuf
				  ; u.dirbuff holds a file name copied from
				  ; a directory 
	mov word ptr [u_count], 10      
	
	mov ax, ROOT_DIR_INODE_NUMBER 

	call read_i ; read 10 bytes of file with i-number
		   ; i.e. read a directory entry
	jc short loc_find_bfn_retn

	mov ax, word ptr [u_nread]

	or ax, ax
	jz short loc_find_bfn_2 ; gives error return 

	mov ax, word ptr [u_dirbuf]

	cmp ax, word ptr [uf_i_number] ; Check i-number of directory entry
	jne short loc_find_bfn_1       ; if same with specified uf_i_number
				       ; it is the boot file 
loc_find_bfn_3:
	call i_get
loc_find_bfn_retn:
	pop si
	retn

loc_find_bfn_2:
	stc
	jmp short loc_find_bfn_retn
	
find_bfn endp


proc_display_startupfile_info proc near
	       ; 06/03/2013             
	       ; 30/11/2012     
	       ; 29/11/2012 ; @@
	       ; 25/11/2012
	      
		mov si, offset Msg_StartupFile_Name
		call UNIX_PRINTMSG

		mov si, offset Boot_File_Name
		call UNIX_PRINTMSG

		mov si, offset Str_Inode_Number
		call UNIX_PRINTMSG

		mov si, word ptr [BSBuffer] ; 06/03/2013
		add si, bs_bf_inode_number 
		mov ax, word ptr [SI]

		mov si, offset Decimal_i_no_str
		mov cx, 5
		call proc_bin_to_decimal

		mov si, offset Decimal_i_no_str 

		mov cx, 4
@@:
		cmp byte ptr [SI], '0'
		ja short @f
		inc si
		loop @b 
@@:
		call UNIX_PRINTMSG

		mov si, offset Str_startup_file_size
		call UNIX_PRINTMSG

		mov ax, word ptr [Inode_size]
		mov si, offset Decimal_size_str
		;mov cx, 5
		mov cl, 5
		call proc_bin_to_decimal

		mov si, offset Decimal_size_str

		mov cl, 4
@@:
		cmp byte ptr [SI], '0'
		ja short @f
		inc si
		loop @b 
@@:
		call UNIX_PRINTMSG

		mov si, offset Str_Bytes
		call UNIX_PRINTMSG

		; 30/11/2012
	
		mov ax, word ptr [Inode_ctim]
		mov dx, word ptr [Inode_ctim]+2

		call convert_from_epoch
		
		mov ax, word ptr [year]
		mov si, offset str_cyear
		;mov cx, 4
		mov cl, 4
		call proc_bin_to_decimal
		
		mov ax, word ptr [month]
		mov si, offset str_cmonth
		mov cl, 2
		call proc_bin_to_decimal

		mov ax, word ptr [day]
		mov si, offset str_cday
		mov cl, 2
		call proc_bin_to_decimal

		mov ax, word ptr [hour]
		mov si, offset str_chour
		mov cl, 2
		call proc_bin_to_decimal

		mov ax, word ptr [minute]
		mov si, offset str_cminute
		mov cl, 2
		call proc_bin_to_decimal

		mov ax, word ptr [second]
		mov si, offset str_csecond
		mov cl, 2
		call proc_bin_to_decimal

		mov ax, word ptr [Inode_mtim]
		mov dx, word ptr [Inode_mtim]+2

		call convert_from_epoch
		
		mov ax, word ptr [year]
		mov si, offset str_myear
		;mov cx, 4
		mov cl, 4
		call proc_bin_to_decimal
		
		mov ax, word ptr [month]
		mov si, offset str_mmonth
		mov cl, 2
		call proc_bin_to_decimal

		mov ax, word ptr [day]
		mov si, offset str_mday
		mov cl, 2
		call proc_bin_to_decimal

		mov ax, word ptr [hour]
		mov si, offset str_mhour
		mov cl, 2
		call proc_bin_to_decimal

		mov ax, word ptr [minute]
		mov si, offset str_mminute
		mov cl, 2
		call proc_bin_to_decimal

		mov ax, word ptr [second]
		mov si, offset str_msecond
		mov cl, 2
		call proc_bin_to_decimal

		mov si, offset Str_SF_date_Time
		call UNIX_PRINTMSG
	       
		retn  

proc_display_startupfile_info endp


proc_bin_to_decimal proc near
	       ; 30/11/2012 (CX input)  
	       ; 25/11/2012 unixboot.asm version        
	       ; 6-5-2009
	       ;  Erdogan Tan
	       ; INPUT: DS:SI = Target location
	       ;        AX = Binary Number
	       ;        CX = Number of digits   
	       ; OUTPUT: Decimal chars at DS:SI
	       ; CX, AX, DX will be changed.

		;push bp
		;push si
loc_reset_str_NumberInput:
		mov byte ptr [SI], "0"
		inc si
		loop loc_reset_str_NumberInput
		mov bp, sp
		xor dx, dx
		mov cx, 10
loc_rediv_NumberInput:
		div cx
		add dl,'0'
		push dx
		xor dx, dx
		dec si
		or ax, ax
		jnz short loc_rediv_NumberInput
loop_popcx_NumberInput: 
		pop dx
		mov byte ptr [SI], dl
		inc si
		cmp bp, sp
		jne short loop_popcx_NumberInput
		;pop si
		;pop bp  
 
		retn

proc_bin_to_decimal endp


print_decimal_number proc near
	; 05/03/2016
	; 03/02/2013
	; 21/01/2013 
	; print decimal number
	;
	; INPUT -> AX = Integer
	; 32/02/2013 CX = Number of decimal digits
	; OUTPUT -> decimal number as string
pdn0:
	mov si, offset dec_num
	;
	mov bx, si
	add si, cx ; 03/02/2013
	mov di, si
	;mov cx, 10
	mov cl, 10
	mov dl, '0'
@@: 
	mov byte ptr [BX], dl
	inc bx
	loop @b
	;
	;xor dl, dl
	;mov byte ptr [BX], dl
	mov bx, 10
	xor dx, dx
pdn_itoa:
	div bx
	; 03/02/2013
	add byte ptr [SI], dl ; 03/02/2013
	and dl, dl
	jnz short @f
	and ax, ax ; 05/03/2016 
	jz short pdn_14
@@:     
	dec si
	xor dl, dl
	jmp short pdn_itoa
pdn_14:
	mov si, offset dec_num
	mov bx, si
@@:     ; leading zeros will not be printed
	mov al, byte ptr [BX] ; 03/02/2013
	cmp al, '0'
	ja short @f
	cmp bx, di
	jnb short @f
	mov al, 20h
	mov byte ptr [BX], al 
	inc bx
	jmp short @b
@@:
	mov ah, 0Eh
	mov bx, 07h
@@:
	lodsb
pdn_putc:       
	int 10h

	cmp si, di
	jna short @b

	;mov al, 20h
	;int 10h
	
	retn 
	
print_decimal_number endp


print_volume_info proc near
	; 06/03/2013
	; 05/03/2013
	; 16/02/2013

	mov bx, word ptr [BSBuffer] ; 06/03/2013
	add bx, bsVolumeSerial+2
	mov cx, 2
	mov di, offset msgVolume_Serial
@@:
	mov ax, word ptr [BX]
	call proc_hex_double
	stosw
	mov ax, dx
	stosw
	dec cx
	jz short @f
	inc di
	sub bx, 2               
	jmp short @b
@@:
	mov si, offset msgVolume_Info
	call UNIX_PRINTMSG
@@:
	mov bx, word ptr [SUPERBLOCK] ; SuperBlock 
		; start of free storage map for disk
@@:
	mov ax, word ptr [BX] ; first word contains # of bytes 
			; in free storage map
	shl ax, 1       ; multiply AX by 8 gives # of blocks
	shl ax, 1
	shl ax, 1       
	push ax         
	mov si, offset msgVol_Size_Hdr
	call UNIX_PRINTMSG
	pop ax
	push ax
	mov cl, 4 ; mov cx, 4
	call print_decimal_number
	mov si, offset msgVolume_Size
	call UNIX_PRINTMSG
	pop cx          ; cx = bit count of free storage map
	xor dx, dx ; mov dx, 0
	xor bl, bl ; xor bx, bx
	mov si, word ptr [SUPERBLOCK]
	add si, 2
	mov di, 16
pvi_size_loop1:
	lodsw
	or ax, ax
	jz short pvi_size_loop3
	push cx
	mov cx, di
pvi_size_loop2:
	shr ax, 1
	jnc short @f
	inc bx
@@:
	loop pvi_size_loop2
	pop cx          
pvi_size_loop3:
	add dx, di
	cmp dx, cx    
	jb short pvi_size_loop1

	push bx
	mov si, offset msgVol_freeblocks_Hdr
	call UNIX_PRINTMSG
	pop ax ; # of free blocks
	mov cx, 4       
	call print_decimal_number
	mov si, offset msgVolume_freeblocks
	call UNIX_PRINTMSG

@@:
	mov bx, word ptr [SUPERBLOCK]
	mov ax, word ptr [BX]
	add ax, 2
	add bx, ax ; 06/03/2013
		; start of inode map for disk
@@:
	mov ax, word ptr [BX] ; first word contains # of bytes 
			; in inode map
	shl ax, 1       ; multiply AX by 8 gives # of inodes
	shl ax, 1
	shl ax, 1
	push bx 
	push ax         
	mov si, offset msgVol_icount_Hdr
	call UNIX_PRINTMSG
	pop ax
	push ax
	mov cl, 4 ; mov cx, 4
	call print_decimal_number
	mov si, offset msgVolume_icount
	call UNIX_PRINTMSG
	pop cx          ; cx = bit count of inode map
	pop si          ; inode map offset
	xor dx, dx ; mov dx, 0
	xor bl, bl ; xor bx, bx
	mov di, 16
pvi_icount_loop1:
	lodsw
	;cmp ax, 0FFFFh
	;je short pvi_icount_loop3
	inc ax
	jz short  pvi_icount_loop3
	dec ax
	push cx
	mov cx, di
pvi_icount_loop2:
	shr ax, 1
	jc short @f
	inc bx
@@:
	loop pvi_icount_loop2
	pop cx          
pvi_icount_loop3:
	add dx, di
	cmp dx, cx    
	jb short pvi_icount_loop1

	push bx
	mov si, offset msgVol_free_icount_Hdr
	call UNIX_PRINTMSG
	pop ax ; # of free inodes
	mov cx, 4       
	call print_decimal_number
	mov si, offset msgVolume_free_icount
	call UNIX_PRINTMSG

	retn    
	
print_volume_info endp


proc_hex_double  proc near
	; 16/02/2013 (AX:DX)
	; 28/01/2002 (DX:AX)
	; From binary (word) to hexadecimal (character) converter
	;
	; input -> AX = word (binary number) to be converted
	; output -> AX = First 2 characters of hexadecimal number
	; output -> DX = Last 2 characters of hexadecimal number

	push cx
	xor dx, dx
	mov cx, 10h
	div cx      ; Q in AX, R in DX (DL)
	push dx     ; DH= 0, R in DL <- CX= 10h 
	xor dl, dl
	div cx      ; DH= 0, R in DL, AX <= FFh
	div cl      ; AL <= 0Fh
		    ; R in AH, Q in AL
	pop cx      ; R in CL
	mov dh, cl
	
	or dx,'00'

	cmp dl,'9'
	jna short pass_cc_dl
	add dl,7
pass_cc_dl:
	cmp dh,'9'
	jna short pass_cc_dh
	add dh,7
pass_cc_dh:
	or ax, '00'

	cmp al,'9'
	jna short pass_cc_al
	add al,7
pass_cc_al:
	cmp ah,'9'
	jna short pass_cc_ah
	add ah,7
pass_cc_ah:
	pop cx

	retn

proc_hex_double  endp


show_inode  proc near
	; 05/03/2013
	; 17/02/2013
	; print inode details
	; Format: inode <decimal number>, iget <decimal number>
	; INPUT -> AX <> 0 -> Current Inode [ii]
	;          AX = 0 -> use inode number input
	;
	and ax, ax
	jnz short show_inode_7
	mov word ptr [arg], ax ; 0
	xor dx, dx
show_inode_1:
	lodsb
	cmp al, '0'
	jb short show_inode_4
	cmp al, '9'
	ja short show_inode_stc_retn ; cmc
	sub al, '0'
show_inode_2:
	or dx, dx
	jnz short show_inode_5
show_inode_3:
	mov dx, ax
	jmp short show_inode_1
show_inode_4:
	or dx, dx
	jz short show_inode_stc_retn
	cmp al, 20h
	jna short show_inode_6
show_inode_stc_retn:
	cmc
show_inode_retn:
	retn
show_inode_5:
	cmp dx, 256
	jnb short show_inode_stc_retn
	mov ah, dl
	mov dl, al
	mov al, 10
	mul ah
	add dx, ax 
	jmp short show_inode_1
show_inode_6:
	mov bx, word ptr [SUPERBLOCK]
	mov ax, word ptr [BX]
	add ax, 2
	mov bx, ax
	mov ax, word ptr [BX] ; inode map bytes
	shl ax, 1
	shl ax, 1
	shl ax, 1 ; inode count
	add ax, 40 ; + device file inodes
	cmp ax, dx
	jb short show_inode_retn ; not a valid i-number
	mov ax, dx
	mov word ptr [arg], ax
	; ax = i-number
	call i_get
	jc short show_inode_retn
show_inode_7:
	;mov ax, word ptr [ii]
	call proc_hex_double
	mov word ptr [txt_inode_number], ax
	mov word ptr [txt_inode_number]+2, dx
	mov ax, word ptr [inode_flgs]
	push ax
	call proc_hex_double
	mov word ptr [txt_inode_flags_h], ax
	mov word ptr [txt_inode_flags_h]+2, dx
	pop dx
	mov di, offset txt_inode_flags_b
	mov cx, 16
@@:
	xor al, al ; 0
	shl dx, 1
	adc al, '0'                     
	stosb
	loop @b
	mov ax, word ptr [inode_nlks]  ; & uid
	call proc_hex_double
	mov word ptr [txt_inode_nlks], dx
	mov word ptr [txt_inode_uid], ax
	mov ax, word ptr [inode_size]
	call proc_hex_double
	mov word ptr [txt_inode_size], ax
	mov word ptr [txt_inode_size]+2, dx
	mov cl, 8
	mov si, offset inode_dskp
	mov di, offset txt_inode_dskp
@@:
	lodsw
	call proc_hex_double    
	stosw
	mov ax, dx
	stosw
	dec cl
	jz short @f
	inc di
	inc di
	jmp short @b
@@:
	;mov si, offset inode_ctim
	mov ax, word ptr [SI]
	mov dx, word ptr [SI]+2
	push dx
	push ax
	push dx
	call proc_hex_double
	mov word ptr [txt_inode_ctim_h]+4, ax   
	mov word ptr [txt_inode_ctim_h]+6, dx
	pop ax
	call proc_hex_double
	mov word ptr [txt_inode_ctim_h], ax     
	mov word ptr [txt_inode_ctim_h]+2, dx
	pop ax
	pop dx
	call convert_from_epoch
	mov ax, word ptr [year]
	mov si, offset txt_inode_cyear
	;mov cx, 4
	mov cl, 4
	call proc_bin_to_decimal
	mov ax, word ptr [month]
	mov si, offset txt_inode_cmonth
	mov cl, 2
	call proc_bin_to_decimal
	mov ax, word ptr [day]
	mov si, offset txt_inode_cday
	mov cl, 2
	call proc_bin_to_decimal
	mov ax, word ptr [hour]
	mov si, offset txt_inode_chour
	mov cl, 2
	call proc_bin_to_decimal
	mov ax, word ptr [minute]
	mov si, offset txt_inode_cminute
	mov cl, 2
	call proc_bin_to_decimal
	mov ax, word ptr [second]
	mov si, offset txt_inode_csecond
	mov cl, 2
	call proc_bin_to_decimal
	mov si, offset inode_mtim
	mov ax, word ptr [SI]
	mov dx, word ptr [SI]+2
	push dx
	push ax
	push dx
	call proc_hex_double
	mov word ptr [txt_inode_mtim_h]+4, ax   
	mov word ptr [txt_inode_mtim_h]+6, dx
	pop ax
	call proc_hex_double
	mov word ptr [txt_inode_mtim_h], ax     
	mov word ptr [txt_inode_mtim_h]+2, dx
	pop ax
	pop dx
	call convert_from_epoch
	mov ax, word ptr [year]
	mov si, offset txt_inode_myear
	;mov cx, 4
	mov cl, 4
	call proc_bin_to_decimal
	mov ax, word ptr [month]
	mov si, offset txt_inode_mmonth
	mov cl, 2
	call proc_bin_to_decimal
	mov ax, word ptr [day]
	mov si, offset txt_inode_mday
	mov cl, 2
	call proc_bin_to_decimal
	mov ax, word ptr [hour]
	mov si, offset txt_inode_mhour
	mov cl, 2
	call proc_bin_to_decimal
	mov ax, word ptr [minute]
	mov si, offset txt_inode_mminute
	mov cl, 2
	call proc_bin_to_decimal
	mov ax, word ptr [second]
	mov si, offset txt_inode_msecond
	mov cl, 2
	call proc_bin_to_decimal
	mov ax, word ptr [inode_reserved]
	call proc_hex_double 
	mov word ptr [txt_inode_reserved], ax   
	mov word ptr [txt_inode_reserved]+2, dx
@@:
	mov si, offset msg_inode_details        
	call UNIX_PRINTMSG
	retn

show_inode endp


load_kernel proc near
	; 06/03/2013
	;
	; loads unix kernel file       
	;
	; INPUT -> u_namep = unix kernel/file name address
	; unix kernel will be loaded at 'kernel_loading_segment'
	;

load_k_1:
	call name_i
	jc short @f
load_k_2:
	call i_get
	jc short @f

	mov bx, inode_flgs

	test word ptr [BX], 10h ; executable file attribute bit
	jz short load_k_stc 

	mov bx, inode_size

	xor ax, ax 

	cmp word ptr [BX], ax ; 0
	jna short load_k_stc   

	mov word ptr [u_off], ax  ; 0
	mov word ptr [u_base], ax ; 0
	
	;mov bx, inode_size
	mov ax, word ptr [BX]
	mov word ptr [u_count], ax

	mov ax, kernel_loading_segment
	mov word ptr [EXTRA_SEGMENT], ax

	mov ax, word ptr [ii]
	call read_i     
	jc short load_k_retn

	mov cx, word ptr [u_nread]
	mov bx, inode_size
	cmp cx, word ptr [BX]

load_k_retn:
	mov ax, ds
	mov word ptr [EXTRA_SEGMENT], ax
@@:
	retn

load_k_stc:
	stc
	retn

load_kernel endp


align 2 ; 05/03/2013
PhysicalDriveNumber: db 0
db 0

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  messages
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

UNIX_Welcome:
		db 'Retro UNIX 8086 v1', 0
Boot_Msg:
		db 0Dh, 0Ah
		db 'Boot: '
		db 0
align 2 ; 05/03/2013
unix_cdrv:
		db 0Dh, 0Ah
UNIX_FD_Name:
		db 'fd'
UNIX_FD_Number:
		db '0:'

unix_cdir:      db '/'
		db 37 dup(0)

CDirOffset:     dw 0

CursorColumn:   dw 0

pdir:           dw 0 

arg:            dw 0

msg_unix_drv_read_error:
		db 0Dh, 0Ah
		db "Drive not ready or read error!"
		db 0Dh, 0Ah, 0

Msg_StartupFile_Name:
		db 0Dh, 0Ah
		db "Startup File Name : ", 0
error_msg:
		db 0Dh, 0Ah
		db 'Error !'
UNIX_CRLF:
		db 0Dh, 0Ah, 0

RetryCount:     dw 0

DirFileName:    db 20h ; 06/01/2013

BOOT_FILE_NAME: db 9 dup(0)

uf_i_number: dw 0 ; 25/11/2012

bootfile_inode: 
inode:
inode_flgs:     dw 801Eh ; Flags (1000000000011110b)
inode_nlks:     db 1    ; number of links 
inode_uid:      db 0    ; user ID (0 = root)
inode_size:     dw 0    ; file size
inode_dskp:     dw 8 dup (0) ; indirect or contents blocks
inode_ctim:     dd 0    ; creation date & time
inode_mtim:     dd 0    ; modification date & time
inode_reserved: dw 0    ; unused

align 2 ; 05/03/2013
db 0FFh

U:
u_uid: db 0
u_cdir: dw ROOT_DIR_INODE_NUMBER
u_namep: dw 0
u_dirp: dw 0
u_base: dw 0
u_off: dw 0
u_count: dw 0
u_nread: dw 0
u_dirbuf: db 10 dup(0)

ii: dw 0
buff_s: dw 0

year: dw 1970
month: dw 1
day: dw 1
hour: dw 0
minute: dw 0
second: dw 0

DMonth:
dw 0
dw 31
dw 59
dw 90
dw 120
dw 151
dw 181
dw 212
dw 243
dw 273
dw 304
dw 334

; 25/11/2012
str_inode_number:
		db 0Dh, 0Ah
		db 'Startup File I-Number: ', 0
Decimal_i_no_str:               
		db 6 dup (0)

Str_startup_file_size:
		db 0Dh, 0Ah
		db 'Startup File Size : ', 0
Str_Bytes:
		db ' bytes', 0

Decimal_size_str: db 6 dup (0)

Str_sf_date_time:
		db 0Dh, 0Ah
		db 'Creating Date & Time    : '
Str_cday:       db '00'
		db '/'
Str_cmonth:     db '00'
		db '/'
Str_cyear:      db '0000'
		db 20h, 20h
Str_chour:      db '00'
		db ':'
Str_cminute:    db '00'
		db ':'
Str_csecond:    db '00'
		db 0Dh, 0Ah
		db 'Last Modif. Date & Time : '
Str_mday:       db '00'
		db '/'
Str_mmonth:     db '00'
		db '/'
Str_myear:      db '0000'
		db 20h, 20h
Str_mhour:      db '00'
		db ':'
Str_mminute:    db '00'
		db ':'
Str_msecond:    db '00'
		db 0Dh, 0Ah, 0

;23/02/2013
list_count: db 0FFh
; 20/01/2013
ls_option: db 0
; 21/01/2013
dec_num: db 10 dup(20h) ; 02/03/2012, 3 bytes -> 10 bytes
db 0

;30/12/2012
DotDot:
db '.'
Dot:
db '.'
db 0

;16/02/2013
msgVolume_Info:
		db 0Dh, 0Ah
		db "Retro UNIX 8086 v1 (RUFS) File System", 0Dh, 0Ah
		db "by Erdogan Tan (2013-2016)"
		db 0Dh, 0Ah, 0Dh, 0Ah
		db "Volume Serial No: "
msgVolume_Serial:
		db "0000-0000h"
		db 0Dh, 0Ah, 0
msgVol_Size_Hdr:db "Volume Size : ", 0
msgVolume_Size: ; db "0000" 
		db " blocks", 0Dh, 0Ah, 0
msgVol_freeblocks_Hdr:db "Free Count  : ", 0
msgVolume_freeblocks : ;db "0000" 
		db " blocks", 0Dh, 0Ah, 0                
msgVol_icount_Hdr:
		db "# of Inodes : ", 0
msgVolume_icount:       ; db "0000" 
		db "+40", 0Dh, 0Ah, 0
msgVol_free_icount_Hdr:db 'Free Inodes : ', 0
msgVolume_free_icount : ;db "0000" 
		db 0Dh, 0Ah, 0
NotFound_msg:
		db 0Dh, 0Ah
		db "Not found !"
		db 0Dh, 0Ah, 0
msgINumber:
		db 0Dh, 0Ah
		db "Inode Number :", 0

msg_inode_details:
		db 0Dh, 0Ah
		db "UNIX V1 I-NODE STRUCTURE DETAILS OF I-NODE "
txt_inode_number:
		db "0000h"
		db 0Dh, 0Ah, 0Dh, 0Ah
		db "Flags : "
txt_inode_flags_h:
		db "0000h"
		db 20h, 20h
		db "["
txt_inode_flags_b:
		db "0000000000000000b"
		db "]"
		db 0Dh, 0Ah
		db "# of Links : "
txt_inode_nlks:
		db "00h"
		db 0Dh, 0Ah
		db "User ID : "
txt_inode_uid:
		db "00h"
		db 0Dh, 0Ah
		db "Size : "
txt_inode_size:
		db "0000h"
		db 0Dh, 0Ah
		db "Disk Blocks : "
txt_inode_dskp:         
		db "0000h 0000h 0000h 0000h "
		db "0000h 0000h 0000h 0000h"
		db 0Dh, 0Ah
		db "Creation Time : "
txt_inode_ctim_h:
		db "00000000h"
		db 20h, 20h
		db "["
txt_inode_cday:
		db "00"
		db "/"
txt_inode_cmonth:
		db "00"
		db "/"
txt_inode_cyear:
		db "0000"
		db ","
txt_inode_chour:
		db "00"
		db ":"
txt_inode_cminute:
		db "00"
		db ":"
txt_inode_csecond:              
		db "00"
		db "]"
		db 0Dh, 0Ah
		db "Modification Time : "
txt_inode_mtim_h:
		db "00000000h"
		db 20h, 20h
		db "["
txt_inode_mday:         
		db "00"
		db "/"
txt_inode_mmonth:
		db "00"
		db "/"
txt_inode_myear:
		db "0000"
		db ","
txt_inode_mhour:
		db "00"
		db ":"
txt_inode_mminute:
		db "00"
		db ":"
txt_inode_msecond:              
		db "00"
		db "]"
		db 0Dh, 0Ah
		db "Unused : "
txt_inode_reserved:             
		db "0000h"
		db 0Dh, 0Ah, 0

Boot_Commands: ; 25/02/2013
db 0Dh, 0Ah
db "BOOT COMMANDS", 0Dh, 0Ah
db "dir <directory name>   : print directory entries without details", 0Dh, 0Ah 
db "ls <directory name>    : print directory entries, ", 27h, "/",  27h," means entry is directory", 0Dh, 0Ah
db "ls -l <directory name> : print directory entries with details", 0Dh, 0Ah
db "cd <directory name>    : change directory", 0Dh, 0Ah
db "show <file name>       : show file, print/display file contents", 0Dh, 0Ah
db "inode <inode number>   : print inode details for (decimal) inode number", 0Dh, 0Ah
db "namei <file name>      : print inode number of file (as decimal)", 0Dh, 0Ah 
db "fs                     : print (current) unix fs (super block) info", 0Dh, 0Ah
db "bootfile               : print startup/boot file details", 0Dh, 0Ah
db "reboot                 : reboot (int 19h)", 0Dh, 0Ah
db "?                      : print boot commands summary (as above)", 0Dh, 0Ah, 0

align 2  ; 05/03/2013
CommandBuffer:  db 74 dup(0)
unix_reboot:    db 0
def_kernel:     db 0
BSBUFFER:       dw 0
SUPERBLOCK:     dw 0
DISKBUFFER:     dw 0
FILEBUFFER:     dw 0
EXTRA_SEGMENT:  dw 0 ; 06/03/2013
; 07/03/2013
waiting_count:  dw 182*3 ; 30 seconds

align 16 ; 05/03/2013

EndOfFile:

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  buffers
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;BSBUFFER:      db 512 dup(0)
;SUPERBLOCK:    db 512 dup(0)
;DISKBUFFER:    db 512 dup(0)
;FILEBUFFER:    db 512 dup(0)
;;;
;;BootStack:

BOOT1  ends

	  end  START_CODE
