String Reversal

By mostafadotnet on Sep 1st, 2006 3:13 pm

This is somewhat a simple project I wrote by getting help from google groups I always recommend.
assemble this code using this command:
nasm -o 1.com 1.asm

ORG 100h

    MOV si,sp ; Save stack pointer!
     
input_loop:
    XOR ax,ax
    INT 16h ; Use int16 to get a keystroke

    CMP al,' ' ; is it a space char?
     JE input_loop ; if space, get another char

    PUSH ax ; Save current char on stack top!
    CMP al,13 ; Terminating CR?
     JNE input_loop

    POP ax ; Get rid of last pushed char (terminating CR)
     JMP test_stack
	
disp_loop:
    POP dx ; DL will get the pushed char
    MOV ah,2
    INT 21h

test_stack:
    CMP si,sp ; Is the stack back where we started?
     JNE disp_loop
      
done: ; So,exit
    MOV ax,0x4C00
    INT 0x21

2 Years Ago

debug
e300"choose 1 letter of d' ff. y,Y/R,r/g,G/B,b- Letter to Color: ","$"
e400"the equivalent color is: ","$"
e500"yellow","$"
e600"red","$"
e700"gold","$"
e800"blue","$"
e900"do you to try Again??!! Y/N","$"
e200"invalid inpUt","$"
a100
mov ah, 09
mov dx, 310
int 21
mov ah, 01
int 21
CMP al, 59
JE 012F
CMP al, 79
JE 012F
CMP al, 52
JE 0166
CMP al, 72
JE 0166
CMP al, 47
JE 0187
CMP al, 67
JE 0187
CMP al, 42
JE 01A8
CMP al, 62
JE 01A8
JNE 01C5
int 21
mov ah, 02
mov dl, 0a
int 21
mov dl, 0d
int 21
mov ah, 09
mov dx, 400
int 21
mov ah, 09
mov dx, 500
int 21
mov ah, 02
mov dl, 0a
int 21
mov dl, 0d
int 21
mov ah, 09
mov dx, 900
int 21
mov ah, 01
int 21
CMP al, 59
JE 0123
CMP al, 4E
JE 0156
JNE 0175
mov ah, 02
mov dl, 0a
int 21
mov dl, 0d
int 21
mov ah, 09
mov dx, 400
int 21
mov ah, 09
mov dx, 600
int 21
mov ah, 09
mov dx, 900
int 21
JMp 0173
mov ah, 02
mov dl, 0a
int 21
mov dl, 0d
int 21
mov ah, 09
mov dx, 400
int 21
mov ah, 09
mov dx, 700
int 21
mov ah, 09
mov dx, 900
int 21
Jmp 0173
mov ah, 02
mov dl, 0a
int 21
mov dl, 0d
int 21
mov ah, 09
mov dx, 400
int 21
mov ah, 09
mov dx, 800
int 21
mov ah, 09
mov dx, 900
int 21
JMP 0173

jhojho

Newbie Poster

1 post since Oct 2009

Reputation Points: 10

Solved Threads: 0

2 Years Ago

Technically that's not a string reversal. If you were to push your characters into a buffer, then reverse them, that's a string reversal!

But your code appears to be okay! Do you have a specific problem?

wildgoose

Practically a Posting Shark

896 posts since Jun 2009

Reputation Points: 546

Solved Threads: 99

This article has been dead for over three months

You