help with cmp strings

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dosin

Joined: 24 Aug 2007
Posts: 337

dosin 29 Aug 2007, 03:37

I am having trouble comparing strings.. str1 is the inputed string
if I enter '-' it returns noprob

it should only return noprob if I enter -help / -dir / -copy
am I going about this wrong?
Is there a better way of comparing strings?

Like dos- if [key word] go to noprob if not print error and continue..

noprob: is my check point to see if its working :prints valid command!
and continues..

Also I no its not the inputed data str1 - I have verified it by out putting it to the screen

help db '-help'
db 0
dir db '-dir'
db 0
copy db '-copy'
db 0

Code:

mov si,str1
mov di,help
repe cmpsb
test cx,cx

je noprob
jmp con1


con1:

mov si,str1
mov di,dir
repe cmpsb
test cx,cx

je noprob
jmp con2

con2:
mov si,str1
mov di,copy
repe cmpsb
test cx,cx

je noprob
jmp error

error:
mov si,consoleError
call printstr
jmp cont

Thanks in advance for any help!

29 Aug 2007, 03:37

Dex4u

Joined: 08 Feb 2005
Posts: 1601
Location: web

Dex4u 29 Aug 2007, 03:51

Take a look at my MiniDos demo/tut, it has full commented code to do what you want: http://board.flatassembler.net/topic.php?t=5275&start=0
quick example

Code:

;====================================================;;  CLS.            compare command buffer with 'cls' ;;====================================================;        mov   si,CommandBuffer              ; Move the address of CommandBuffer in SI        mov   cx,4                          ; Move number of letters into CX        mov   di,cCLS                       ; Point to label        repe  cmpsb                         ; Test if =.        jne   not_cls                       ; If not =, jump to label not_cls        call  Cls                           ; call our function        call  Cursor                        ; call our function        call  Welcome                       ; call our function        jmp   ExitFound                     ; Jump to label ExitFoundnot_cls:;====================================================;;  TIME.          compare command buffer with 'time' ;;====================================================;        mov   si,CommandBuffer              ; Move the address of CommandBuffer in SI        mov   cx,5                          ; Move number of letters into CX        mov   di,cTIME                      ; Point to label        repe  cmpsb                         ; Test if =.        jne   not_time                      ; If not =, jump to label not_time        call  Time                          ; call time function        jmp   ExitFound                     ; Jump to label ExitFoundnot_time:;more stuff herecCLS            db 'CLS',0cTIME           db 'TIME',0

Note: you need to convert them to uppercase before testing, just in case they write them in upper case.

29 Aug 2007, 03:51

dosin

Joined: 24 Aug 2007
Posts: 337

dosin 29 Aug 2007, 05:17

TY - The problem was I was using bx to count the number of chars entered and was moving it into cx...and then comparing them...
I altered my code to mov cx,5 for -help and so on and it works great!

29 Aug 2007, 05:17

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