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Home » Archives » 30. July 2006

Invert String

July 30, 2006

; convert small letters to capital AND vice-versa

mov ah,0ah
lea dx,parameter
int 21h

mov ah,02
mov dl,0ah
int 21h
mov dl,0dh
int 21h

; initialize
lea si, input
xor cx, cx
mov cl, [actlen]

; We wish to check if character is a letter
; if yes, capitalize small letters and vice-versa
; if no, copy character

invert:
     mov al, [si]
 
     cmp al, 122
     ja skip

     cmp al, 96
     ja capital

     cmp al, 90
     ja skip

     cmp al, 63
     jb skip

     add al, 32
 
     jmp store

capital:
     sub al, 32

store:
     mov [si], al

skip:
     inc si

loop invert

mov ah, 09
lea dx, input
int 21h

int 20h

parameter label byte
maxlen db 0FF
actlen db ?
input db 0FF dup(’$')

 

Posted by phengpheng at 4:51 pm | permalink | comments[1]

Reverse a string

; reverse string

mov ah,0ah
lea dx,parameter
int 21h

mov ah,02
mov dl,0ah
int 21h
mov dl,0dh
int 21h

; initialize

xor cx, cx             ; zero out cx
lea si, origstring    ; si = inputted string
mov cl, [actlen]     ; cl = length of inputted string
dec cl                   ; since string starts from 0 to cl-1
lea di, revstring     ; di = empty
add di, cx   

reverse:
        mov al, [si]  ; get character
        mov [di], al  ; copy to di at ‘cl-1′th position
        dec di   
        inc si
 
 cmp al, ‘$’           ; means end of string
 jne reverse

mov ah, 09
lea dx, revstring
int 21h

int 20h

parameter label byte
maxlen db 0FF
actlen db ?
origstring db 0FF dup(’$')

revstring db 0FF dup (’$')

Posted by phengpheng at 4:49 pm | permalink | Add comment

     

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About Me

A Computer Science graduate who is a fanatic in assembly, java, and j2me programming. Developed BlueVoice system (Direct Voice Communication in Mobile Phones), this system allows mobile users to experience FREE VOICE CALLS

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phengpheng:

Haven’t managed my blog for a long time already because I’m so busy now… Sorry to cause you guyz trouble…

Jun Mark:

hoW tO creaTE a PrOGram thAT woULD oUTpuT ascii table???

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pLZ anSwer mY qUEstions

cutieGurl:

how to convert binary to hexadecimal, decimal and octal?????????please. answer me??????????

mary ann:

kuya, ung binary to decimal converter nyo. mali man? ung sa mga compare mo. ung may 0,9,A,F etc… bad character lumalabaspls rep asap po. tnx

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how to convert decimal to binary to octal and hexadecimal

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aus, i seldom see lady programmers. hehe. keep it up. and oh yeah, i guess i saw you during the MICT Quiz Show held in cdo. :)
keep up the codes!

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