I have this kernel with the shell, and I'm trying to put the time and date commands in it but can't seem to make it work. It shows no error while compiling but it doesn't do anything when I test it. Can anyone tell me what I'm doing wrong here?
Here's the code so far:
;*****************start of the kernel code***************
[org 0x000]
[bits 16]
[SEGMENT .text]
;START #####################################################
mov ax, 0x0100 ;location where kernel is loaded
mov ds, ax
mov es, ax
cli
mov ss, ax ;stack segment
mov sp, 0xFFFF ;stack pointer at 64k limit
sti
push dx
push es
xor ax, ax
mov es, ax
cli
mov word [es:0x21*4], _int0x21 ; setup interrupt service
mov [es:0x21*4+2], cs
sti
pop es
pop dx
mov si, strWelcomeMsg ; load message
mov al, 0x01 ; request sub-service 0x01
int 0x21
call _shell ; call the shell
int 0x19 ; reboot
;END #######################################################
_int0x21:
_int0x21_ser0x01: ;service 0x01
cmp al, 0x01 ;see if service 0x01 wanted
jne _int0x21_end ;goto next check (now it is end)
_int0x21_ser0x01_start:
lodsb ; load next character
or al, al ; test for NUL character
jz _int0x21_ser0x01_end
mov ah, 0x0E ; BIOS teletype
mov bh, 0x00 ; display page 0
mov bl, 0x07 ; text attribute
int 0x10 ; invoke BIOS
jmp _int0x21_ser0x01_start
_int0x21_ser0x01_end:
jmp _int0x21_end
_int0x21_end:
iret
_shell:
_shell_begin:
;move to next line
call _display_endl
;display prompt
call _display_prompt
;get user command
call _get_command
;split command into components
call _split_cmd
;check command & perform action
; empty command
_cmd_none:
mov si, strCmd0
cmp BYTE [si], 0x00
jne _cmd_ver ;next command
jmp _cmd_done
; display version
_cmd_ver:
mov si, strCmd0
mov di, cmdVer
mov cx, 4
repe cmpsb
jne _cmd_cls ;next command
call _display_endl
mov si, strOsName ;display version
mov al, 0x01
int 0x21
call _display_space
mov si, txtVersion ;display version
mov al, 0x01
int 0x21
call _display_space
mov si, strMajorVer
mov al, 0x01
int 0x21
mov si, strMinorVer
mov al, 0x01
int 0x21
jmp _cmd_done
_cmd_cls:
mov si, strCmd0
mov di, cmdCls
mov cx, 4
repe cmpsb
jne _cmd_date ;next command
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
call _display_endl
mov bh, 0
mov dl, 0
mov dh, 00
mov ah, 02
int 10h
jmp _cmd_done
_cmd_date:
mov si, strCmd0
mov di, cmdDate
mov cx, 4
repe cmpsb
jne _cmd_time ;next command
jmp overdata
overdata:
mov ah,4
int 1Ah
mov di,datestring
mov al,dh
call byte2hex
mov al,'-'
stosb
mov al,dl
call byte2hex
mov al,'-'
stosb
mov ax,cx
call word2hex
mov al,'$'
stosb
mov dx,datestring ;just like "Hello World!"
mov ah,9
int 21h
mov ah,4Ch
int 21h
word2hex:
mov bx,ax
shr ax,12
call nyb2hex
mov ax,bx
shr ax,8
call nyb2hex
mov ax,bx
byte2hex:
mov bx,ax
shr ax,4
call nyb2hex
mov ax,bx
nyb2hex:
and al,0Fh
cmp al,10
;sbb al,105
;das
jc okdigit
add al,7
okdigit:
add al,30h
;int 029h
stosb
ret
jmp _cmd_done
_cmd_time:
mov si, strCmd0
mov di, cmdTime
mov cx, 4
repe cmpsb
jne _cmd_hlp
jmp _WasteTime
global _WasteTime
_WasteTime:
mov bx, sp
mov bx, [ss:bx+02h]
push si
push di
mov ah, 00h
int 1Ah
mov di, cx
mov si, dx
.Waster:
mov ah, 00h
int 1Ah
sub dx, si
sbb cx, di
cmp cx, 0
jne .EndOfProc
cmp dx, bx
jb .Waster
.EndOfProc:
pop di
pop si
ret
jmp _cmd_done
_cmd_hlp:
mov si, strCmd0
mov di, cmdHlp
mov cx, 4
repe cmpsb
jne _cmd_abt ;next command
call _display_endl
mov si, strHelp ;display help
mov al, 0x01
int 0x21
call _display_space
mov si, txtHelp ;display help
mov al, 0x01
int 0x21
mov si, strCmdOne ;display command
mov al, 0x01
int 0x21
mov si, strCmdTwo
mov al, 0x01
int 0x21
mov si, strCmdThree
mov al, 0x01
int 0x21
mov si, strCmdFour
mov al, 0x01
int 0x21
mov si, strCmdFive
mov al, 0x01
int 0x21
mov si, strCmdSix
mov al, 0x01
int 0x21
jmp _cmd_done
_cmd_abt:
mov si, strCmd0
mov di, cmdAbt
mov cx, 4
repe cmpsb
jne _cmd_exit ;next command
call _display_endl
mov si, txtAbout ;display about
mov al, 0x01
int 0x21
call _display_space
mov si, strAbout ;display about
mov al, 0x01
int 0x21
call _display_space
mov si, strMajorAbt
mov al, 0x01
int 0x21
mov si, strMinorAbt
mov al, 0x01
int 0x21
jmp _cmd_done
; exit shell
_cmd_exit:
mov si, strCmd0
mov di, cmdExit
mov cx, 5
repe cmpsb
jne _cmd_unknown ;next command
je _shell_end ;exit from shell
_cmd_unknown:
call _display_endl
mov si, msgUnknownCmd ;unknown command
mov al, 0x01
int 0x21
_cmd_done:
;call _display_endl
jmp _shell_begin
_shell_end:
ret
_get_command:
;initiate count
mov BYTE [cmdChrCnt], 0x00
mov di, strUserCmd
_get_cmd_start:
mov ah, 0x10 ;get character
int 0x16
cmp al, 0x00 ;check if extended key
je _extended_key
cmp al, 0xE0 ;check if new extended key
je _extended_key
cmp al, 0x08 ;check if backspace pressed
je _backspace_key
cmp al, 0x0D ;check if Enter pressed
je _enter_key
mov bh, [cmdMaxLen] ;check if maxlen reached
mov bl, [cmdChrCnt]
cmp bh, bl
je _get_cmd_start
;add char to buffer, display it and start again
mov [di], al ;add char to buffer
inc di ;increment buffer pointer
inc BYTE [cmdChrCnt] ;inc count
mov ah, 0x0E ;display character
mov bl, 0x07
int 0x10
jmp _get_cmd_start
_extended_key: ;extended key - do nothing now
jmp _get_cmd_start
_backspace_key:
mov bh, 0x00 ;check if count = 0
mov bl, [cmdChrCnt]
cmp bh, bl
je _get_cmd_start ;yes, do nothing
dec BYTE [cmdChrCnt] ;dec count
dec di
;check if beginning of line
mov ah, 0x03 ;read cursor position
mov bh, 0x00
int 0x10
cmp dl, 0x00
jne _move_back
dec dh
mov dl, 79
mov ah, 0x02
int 0x10
mov ah, 0x09 ; display without moving cursor
mov al, ' '
mov bh, 0x00
mov bl, 0x07
mov cx, 1 ; times to display
int 0x10
jmp _get_cmd_start
_move_back:
mov ah, 0x0E ; BIOS teletype acts on backspace!
mov bh, 0x00
mov bl, 0x07
int 0x10
mov ah, 0x09 ; display without moving cursor
mov al, ' '
mov bh, 0x00
mov bl, 0x07
mov cx, 1 ; times to display
int 0x10
jmp _get_cmd_start
_enter_key:
mov BYTE [di], 0x00
ret
_split_cmd:
;adjust si/di
mov si, strUserCmd
;mov di, strCmd0
;move blanks
_split_mb0_start:
cmp BYTE [si], 0x20
je _split_mb0_nb
jmp _split_mb0_end
_split_mb0_nb:
inc si
jmp _split_mb0_start
_split_mb0_end:
mov di, strCmd0
_split_1_start: ;get first string
cmp BYTE [si], 0x20
je _split_1_end
cmp BYTE [si], 0x00
je _split_1_end
mov al, [si]
mov [di], al
inc si
inc di
jmp _split_1_start
_split_1_end:
mov BYTE [di], 0x00
;move blanks
_split_mb1_start:
cmp BYTE [si], 0x20
je _split_mb1_nb
jmp _split_mb1_end
_split_mb1_nb:
inc si
jmp _split_mb1_start
_split_mb1_end:
mov di, strCmd1
_split_2_start: ;get second string
cmp BYTE [si], 0x20
je _split_2_end
cmp BYTE [si], 0x00
je _split_2_end
mov al, [si]
mov [di], al
inc si
inc di
jmp _split_2_start
_split_2_end:
mov BYTE [di], 0x00
;move blanks
_split_mb2_start:
cmp BYTE [si], 0x20
je _split_mb2_nb
jmp _split_mb2_end
_split_mb2_nb:
inc si
jmp _split_mb2_start
_split_mb2_end:
mov di, strCmd2
_split_3_start: ;get third string
cmp BYTE [si], 0x20
je _split_3_end
cmp BYTE [si], 0x00
je _split_3_end
mov al, [si]
mov [di], al
inc si
inc di
jmp _split_3_start
_split_3_end:
mov BYTE [di], 0x00
;move blanks
_split_mb3_start:
cmp BYTE [si], 0x20
je _split_mb3_nb
jmp _split_mb3_end
_split_mb3_nb:
inc si
jmp _split_mb3_start
_split_mb3_end:
mov di, strCmd3
_split_4_start: ;get fourth string
cmp BYTE [si], 0x20
je _split_4_end
cmp BYTE [si], 0x00
je _split_4_end
mov al, [si]
mov [di], al
inc si
inc di
jmp _split_4_start
_split_4_end:
mov BYTE [di], 0x00
;move blanks
_split_mb4_start:
cmp BYTE [si], 0x20
je _split_mb4_nb
jmp _split_mb4_end
_split_mb4_nb:
inc si
jmp _split_mb4_start
_split_mb4_end:
mov di, strCmd4
_split_5_start: ;get last string
cmp BYTE [si], 0x20
je _split_5_end
cmp BYTE [si], 0x00
je _split_5_end
mov al, [si]
mov [di], al
inc si
inc di
jmp _split_5_start
_split_5_end:
mov BYTE [di], 0x00
ret
_display_space:
mov ah, 0x0E ; BIOS teletype
mov al, 0x20
mov bh, 0x00 ; display page 0
mov bl, 0x07 ; text attribute
int 0x10 ; invoke BIOS
ret
_display_endl:
mov ah, 0x0E ; BIOS teletype acts on newline!
mov al, 0x0D
mov bh, 0x00
mov bl, 0x07
int 0x10
mov ah, 0x0E ; BIOS teletype acts on linefeed!
mov al, 0x0A
mov bh, 0x00
mov bl, 0x07
int 0x10
ret
_display_prompt:
mov si, strPrompt
mov al, 0x01
int 0x21
ret
[SEGMENT .data]
strWelcomeMsg db "Welcome to GeoLiz NaviOS", 0x00
strPrompt db "==>", 0x00
cmdMaxLen db 255 ;maximum length of commands
strOsName db "GeoLiz", 0x00 ;OS details
strMajorVer db "0", 0x00
strMinorVer db ".7", 0x0D, 0x0A, 0x00
strHelp db "List of ", 0x00 ;Help
strCmdOne db "ver-Get version ", 0x0D, 0x0A, 0x00
strCmdTwo db "exit-Reboot ", 0x0D, 0x0A, 0x00
strCmdThree db "date-Get date today ", 0x0D, 0x0A, 0x00
strCmdFour db "time-Get time now ", 0x0D, 0x0A, 0x00
strCmdFive db "help-list commands ", 0x0D, 0x0A, 0x00
strCmdSix db "abt-about creator", 0x0D, 0x0A, 0x00
strAbout db "GeoLiz NaviOS", 0x0D, 0x0A, 0x00 ;about OS
strMajorAbt db "Creators: Geo and Liz", 0x0D, 0x0A, 0x00
strMinorAbt db " Created: Sept.20,2007", 0x0D, 0x0A, 0x00
cmdVer db "ver", 0x00 ; internal commands
cmdExit db "exit", 0x00
cmdDate db "date", 0x00
cmdTime db "time", 0x00
cmdHlp db "help", 0x00
cmdAbt db "abt", 0x00
cmdCls db "cls", 0x00
datestring times 0Eh db 0
txtVersion db "Version", 0x00 ;messages and other strings
txtHelp db "Commands:", 0x0D, 0x0A, 0x00
txtAbout db "About", 0x0D, 0x0A, 0x00
msgUnknownCmd db "Unknown command!", 0x00
[SEGMENT .bss]
strUserCmd resb 256 ;buffer for user commands
cmdChrCnt resb 1 ;count of characters
strCmd0 resb 256 ;buffers for the command components
strCmd1 resb 256
strCmd2 resb 256
strCmd3 resb 256
strCmd4 resb 256
;********************end of the kernel code********************