Related
I wanna print what the user inputted first. However, it displays the converted uppercase already before the result.
Here's my code:
org 100h
BEGIN:
LEA DX, DASH1
MOV AH, 9
INT 21H
LEA DX,LOWERCASE
MOV AH,09H
INT 21H
LEA SI,STR1
MOV AH,01H
READ:
INT 21H
MOV BL,AL
CMP AL,0DH
JE DISPLAY
XOR AL,20H
MOV [SI],AL
INC SI
JMP READ
DISPLAY:
MOV AL,"$"
MOV [SI],AL
LEA DX,UPPERCASE
MOV AH,09H
INT 21H
LEA DX, STR1
MOV AH, 09H
INT 21H
MOV DL, BH ; space
MOV AH, 02H
INT 21H
LEA DX, UPPERCASE_
MOV AH, 9
INT 21H
LEA DX,STR1
MOV AH,09H
INT 21H
LEA DX, DASH2
MOV AH, 9
INT 21H
MOV AH,4CH
INT 21H
ret
LOWERCASE DB 0DH,0AH,0AH, " Input a 5-letter string: $"
UPPERCASE DB 0DH,0AH, " The uppercase equivalent of $"
UPPERCASE_ DB "is $"
DASH1 DB 0AH,0DH, " ================================================================= $"
DASH2 DB 0AH,0AH,0DH, " ================================================================= $"
STR1 DB 255 DUP(?)
Output:
Input a 5-letter string: asdfg
The uppercase equivalent of ASDFG is ASDFG
^ i want this part to print as `asdfg`
making it The uppercase equivalent of asdfg is ASDFG
P.S. also, how do I make the string limited to 5 only? Its because the string a user can input can exceed more than 5. Any tips?
==============================================================================
You are displaying strings UPPERCASE, STR1, UPPERCASE_,STR1, respectively, no wonder that STR1 remains the same. You need to reserve one more string STRorig where you should store the obtained character before its case is changed.
You can use DI to address STRorig and then perform STOSB for saving original AL to ES:DI and incrementing DI.
When you want to limit the size of input string, compare SI with STR1 + 5 and if it's above, act as if AL was equal to 0DH.
I need help in combining two programs I have and I can't seem to get it working for me. Don't get the desired output.
So here's my problem statement:
Combine Two separate strings in a third string and display it, Where the first String is as it is and the second string is reversed.
Example:
Input:
String 1: 'Hello'
String 2: '.dlroW '
Output:
'Hello World.'
end of Example.
Now there are two ways we can go about this.
First: Use string functions.(Preferred)
Now I am fairly new to learning Assembly Language so I would like to do it using string functions so I can learn something New.
Second: Without using string functions.
Another Approach is if someone can help combining two programs, One for the concatenation of the string and the other for reversal, Note that I have written the two individual programs and they run well without any hiccups, I just can't seem to do it together. How I am going about with this is before concatenating the string I am trying to reverse it, then proceeding with the addition of the second string. But I can't seem to get it working. I've tried to the best of my knowledge.
//Concatenation Code
.model tiny
.data
msg1 db 10,13,"Enter the string 1: $"
cat db 30 DUP('$')
msg2 db 10,13,"Enter the string 2: $"
msg3 db 10,13,"Concatenated string is: $"
.code
mov ax,#data
mov ds,ax
lea dx,msg1
mov ah,09h
int 21h
lea si,cat
up: mov ah,01h
int 21h
mov [si],al
inc si
cmp al,0dh
jnz up
lea dx,msg2
mov ah,09h
int 21h
dec si
up1: mov ah,01h
int 21h
mov [si],al
inc si
cmp al,0dh
jnz up1
lea dx,msg3
mov ah,09h
int 21h
lea dx,cat
mov ah,09h
int 21h
mov ah,4ch
int 21h
end`
Here's Part 2
//Reversal Code
.model tiny
.data
msg1 db 10,13,"enter the string: $"
string db 40 DUP('$')
rev db 40 DUP('$')
msg2 db 10,13,"reverse string is: $"
.code
mov ax,#data
mov ds,ax
lea dx,msg1
mov ah,09h
int 21h
mov ah,0ah
lea dx,string
int 21h
lea si,string
lea di,rev
mov cl,[si+1]
mov ch,00h
add di,cx
inc si
inc si
up: mov al,[si]
mov [di],al
inc si
dec di
loop up
inc di
mov ah,09h
lea dx,msg2
int 21h
mov ah,09h
lea dx,[di]
int 21h
mov ah,4ch
int 21h
end
And Here is the code I came Up with by combining those two.
//That's the code I tried Combining
.model tiny
.data
.model tiny
.data
msg1 db 10,13,"Enter string1: $"
cat db 30 DUP('$')
msg2 db 10,13,"Enter string2: $"
msg3 db 10,13,"Concatenated string is: $"
.code
mov ax, #data
mov ds,ax
lea dx,msg1
mov ah,09h
int 21h
lea si,cat
up: mov ah,01h
int 21h
mov [si],al
inc si
cmp al,0dh
jnz up
lea dx, msg2
mov ah,09h
int 21h
dec si
up2:mov al,[si]
mov [di],al
inc si
dec di
loop up2
inc di
up1:mov ah,01h
int 21h
mov [si],al
inc si
cmp al,0dh
jnz up1
lea dx,msg3
mov ah,09h
int 21h
lea dx,cat
mov ah,09h
int 21h
mov ah,4ch
int 21h
end
My Output
As you can see clearly I have failed at doing either task correctly. So can someone tell me where I am going wrong? Or teach me how to do this using the string Functions?
The up2 loop that tries to do string reversal comes too soon!. You've placed it where the 2nd string (the one that needs reversal) isn't even inputted yet.
If you would have written comments in your program, then you would probably have noticed this yourself.
This up2 loop uses the LOOP instruction that depends on the CX register but your program does not assign any suitable value to CX.
And also your working reversal program is using 2 buffers. Why then do you expect the combo to work from a single buffer?
Define the cat buffer so it can hold both strings.
Define the str buffer so it can hold the second string.
lea dx, msg1
mov ah, 09h ; DOS.PrintString
int 21h
lea di, cat
up: ; Input f i r s t string
mov ah, 01h ; DOS.GetCharacter
int 21h ; -> AL
mov [di], al
inc di
cmp al, 13
jne up
dec di ; Throw out the 13
; This marks the start of the reversed string, VERY IMPORTANT
; So don't change DI while inputting the 2nd string
lea dx, msg2
mov ah, 09h ; DOS.PrintString
int 21h
lea si, str
mov dx, si
up1: ; Input s e c o n d string
mov ah, 01h ; DOS.GetCharacter
int 21h ; -> AL
mov [si], al
inc si
cmp al, 13
jne up1
dec si ; Throw out the 13
cmp si, dx
je done ; Second string was empty. CAN HAPPEN!
up2: ; Reversed copying of s e c o n d string
dec si
mov al, [si]
mov [di], al
inc di
cmp si, dx
ja up2
done:
mov ax, 0A0Dh ; Add a proper carriage return and linefeed to the result
mov [di], ax
mov al, '$' ; Terminate the result with a dollar sign
mov [di+2], al
lea dx, msg3
mov ah, 09h ; DOS.PrintString
int 21h
lea dx, cat
mov ah, 09h ; DOS.PrintString
int 21h
First: Use string functions.(Preferred)
Both in the up loop and in the up2 loop, do you find next pair of instructions:
mov [di], al
inc di
Provided
the direction flag DF is clear so that DI can increment
the ES segment register points to #data
you can replace these 2 instructions by a single STOSB instruction.
This is what needs to go on top of your program:
.code
mov ax, #data
mov ds, ax
mov es, ax
cld
If we allowed ourselves to write a silly sequence of multiple std (set direction flag) and cld (clear direction flag) instructions, we could also replace mov al, [si] with lodsb. Care must be taken to keep a valid SI pointer (*).
dec si ; (*)
up2: ; Reversed copying of s e c o n d string
std
lodsb ; Due to STD, SI will decrement
cld
stosb ; Due to CLD, DI will increment
cmp si, dx
jae up2 ; (*)
done:
mov ax, 0A0Dh ; Add a proper carriage return and linefeed to the result
stosw
mov al, '$' ; Terminate the result with a dollar sign
stosb
In code that sets the direction flag (using std) it is best to end with a cld instruction so the direction flag is in the state we most expect!
I have to build a Base Converter in 8086 assembly .
The user has to choose his based and then put a number,
after then , the program will show him his number in 3 more bases[he bring a decimal number, and after this he will see his number in hex, oct, and bin.
This first question is, how can I convert the number he gave me, from string, to a number?
the sec question is, how can i convert? by RCR, and then adc some variable?
Here is my code:
data segment
N=8
ERROR_STRING_BASE DB ,10,13, " THIS IS NOT A BASE!",10,13, " TRY AGINE" ,10,13," $"
OPENSTRING DB " Welcome, to the Base Convertor",10,13," Please enter your base to convert from:",10,13," <'H'= Hex, 'D'=Dec, 'O'=oct, 'B'=bin>: $"
Hex_string DB "(H)" ,10,13, "$"
Octalic_string DB "(O) ",10,13, "$"
Binar_string DB "(B)",10,13, "$"
Dece_string DB "(D)",10,13, "$"
ENTER_STRING DB ,10,13, " Now, Enter Your Number (Up to 4 digits) ",10,13, "$"
Illegal_Number DB ,10,13, " !!! This number is illegal, lets Start again" ,10,13,"$"
BASED_BUFFER DB N,?,N+1 DUP(0)
Number_buffer db N, ? ,N+1 DUP(0)
TheBase DB N DUP(0)
The_numer DB N DUP(0)
The_binNumber DB 16 DUP(0)
data ends
sseg segment stack
dw 128 dup(0)
sseg ends
code segment
assume ss:sseg,cs:code,ds:data
start: mov ax,data
mov ds,ax
MOV DX,OFFSET OPENSTRING ;PUTS THE OPENING SRTING
MOV AH,9
INT 21H
call EnterBase
CALL CheckBase
HEXBASE: CALL PRINTtheNUMBER
MOV DX,OFFSET Hex_string
MOV AH,9
INT 21h
JMP I_have_the_numberH
oCTALICbASE: CALL PRINTtheNUMBER
MOV DX,OFFSET Octalic_string
MOV AH,9
INT 21h
JMP I_have_the_numberO
BINBASE:CALL PRINTtheNUMBER
MOV DX,OFFSET Binar_string
MOV AH,9
INT 21h
JMP I_have_the_numberB
DECBASE: CALL PRINTtheNUMBER
MOV DX,OFFSET Dece_string
MOV AH,9
INT 21h
JMP I_have_the_numberD
I_have_the_numberH: CALL BINcalculation
CALL OCTcalculation
CALL DECcalculation
I_have_the_numberO: CALL BINcalculation
CALL DECcalculation
CALL HEXcalculation
I_have_the_numberB: CALL OCTcalculation
CALL DECcalculation
CALL HEXcalculation
I_have_the_numberD: CALL BINcalculation
CALL OCTcalculation
CALL HEXcalculation
exit: mov ax, 4c00h
int 21h
EnterBase PROC
MOV DX,OFFSET BASED_BUFFER ; GETS THE BASE
MOV AH,10
INT 21H
LEA DX,BASED_BUFFER[2]
MOV BL,BASED_BUFFER[1]
MOV BH,0
MOV BASED_BUFFER[BX+2],0
LEA SI, BASED_BUFFER[2]
XOR CX, CX
MOV CL, BASED_BUFFER[1]
LEA DI, TheBase
LOL_OF_BASE: MOV DL, [SI]
MOV [DI], DL
INC SI
INC DI
INC AL
RET
EnterBase ENDP
CheckBase proc
CMP TheBase,'H'
JE HEXBASE
CMP TheBase,'h'
JE HEXBASE
CMP TheBase,'O'
JE oCTALICbASE
CMP TheBase,'o'
JE oCTALICbASE
CMP TheBase,'B'
JE BINBASE
CMP TheBase,'b'
JE BINBASE
CMP TheBase,'D'
JE DECBASE
CMP TheBase,'d'
JE DECBASE
CMP TheBase, ' '
je ERRORoFBASE
ERRORoFBASE: MOV DX,OFFSET ERROR_STRING_BASE ;PUTS WORNG BASE Illegal_Number
MOV AH,9
INT 21H
JMP START
CheckBase ENDP
PRINTtheNUMBER PROC
MOV DX,OFFSET ENTER_STRING
MOV AH,9
INT 21h
MOV DX,OFFSET Number_buffer ; GETS THE number
MOV AH,10
INT 21H
LEA DX,Number_buffer[2]
MOV BL,Number_buffer[1]
MOV BH,0
MOV Number_buffer[BX+2],0
LEA SI, Number_buffer[2]
XOR CX, CX
MOV CL, Number_buffer[1]
LEA DI, The_numer
xor AL,AL
LOL_OF_NUMBER_CHECK: MOV DL, [SI]
MOV [DI], DL
INC SI
INC DI
INC AL
CMP AL,5
JE ERRORofNUMBER
LOOP LOL_OF_NUMBER_CHECK
RET
ERRORofNUMBER: MOV DX,OFFSET Illegal_Number ;PUTS WORNG BASE Illegal_Number
MOV AH,9
INT 21H
JMP START
PRINTtheNUMBER ENDP
PROC BINcalculation
XOR CX,CX
XOR AX,AX
MOV CX,4
MOV AX,16
LEA SI, The_binNumber[0]
TheBinarLoop: RCL The_numer,1
ADC [SI],0
INC SI
LOOP TheBinarLoop
ENDP
PROC OCTcalculation
ENDP
PROC DECcalculation
ENDP
PROC HEXcalculation
ENDP
code ends
end start
It should be look like this:
thanks!
שלו לוי
the algorighm to decode ascii strings from ANY base to integer is the same:
result = 0
for each digit in ascii-string
result *= base
result += value(digit)
for { bin, oct, dec } value(digit) is ascii(digit)-ascii('0')
hex is a bit more complicated, you have to check if the value is 'a'-'f', and convert this to 10-15
converting integer to ascii(base x) is similar, you have to divide the value by base until it's 0, and add ascii representation of the remainder at the left
e.g. 87/8= 10, remainder 7 --> "7"
10/8= 1, remainder 2 --> "27"
1/8= 0, remainder 1 --> "127"
Copy-paste next little program in EMU8086 and run it : it will capture a number as string from keyboard, then convert it to numeric in BX. To store the number in "The_numer", you have to do mov The_numer, bl :
.stack 100h
;------------------------------------------
.data
;------------------------------------------
msj1 db 'Enter a number: $'
msj2 db 13,10,'Number has been converted',13,10,13,10,'$'
string db 5 ;MAX NUMBER OF CHARACTERS ALLOWED (4).
db ? ;NUMBER OF CHARACTERS ENTERED BY USER.
db 5 dup (?) ;CHARACTERS ENTERED BY USER.
;------------------------------------------
.code
;INITIALIZE DATA SEGMENT.
mov ax, #data
mov ds, ax
;------------------------------------------
;DISPLAY MESSAGE.
mov ah, 9
mov dx, offset msj1
int 21h
;------------------------------------------
;CAPTURE CHARACTERS (THE NUMBER).
mov ah, 0Ah
mov dx, offset string
int 21h
;------------------------------------------
call string2number
;------------------------------------------
;DISPLAY MESSAGE.
mov ah, 9
mov dx, offset msj2
int 21h
;------------------------------------------
;STOP UNTIL USER PRESS ANY KEY.
mov ah,7
int 21h
;------------------------------------------
;FINISH THE PROGRAM PROPERLY.
mov ax, 4c00h
int 21h
;------------------------------------------
;CONVERT STRING TO NUMBER IN BX.
proc string2number
;MAKE SI TO POINT TO THE LEAST SIGNIFICANT DIGIT.
mov si, offset string + 1 ;<================================ YOU CHANGE THIS VARIABLE.
mov cl, [ si ] ;NUMBER OF CHARACTERS ENTERED.
mov ch, 0 ;CLEAR CH, NOW CX==CL.
add si, cx ;NOW SI POINTS TO LEAST SIGNIFICANT DIGIT.
;CONVERT STRING.
mov bx, 0
mov bp, 1 ;MULTIPLE OF 10 TO MULTIPLY EVERY DIGIT.
repeat:
;CONVERT CHARACTER.
mov al, [ si ] ;CHARACTER TO PROCESS.
sub al, 48 ;CONVERT ASCII CHARACTER TO DIGIT.
mov ah, 0 ;CLEAR AH, NOW AX==AL.
mul bp ;AX*BP = DX:AX.
add bx,ax ;ADD RESULT TO BX.
;INCREASE MULTIPLE OF 10 (1, 10, 100...).
mov ax, bp
mov bp, 10
mul bp ;AX*10 = DX:AX.
mov bp, ax ;NEW MULTIPLE OF 10.
;CHECK IF WE HAVE FINISHED.
dec si ;NEXT DIGIT TO PROCESS.
loop repeat ;COUNTER CX-1, IF NOT ZERO, REPEAT.
ret
endp
The proc you need is string2number. Pay attention inside the proc : it uses a variable named "string", you have to change it by the name of your own variable. After the call the result is in BX: if the number is less than 256, you can use the number in BL.
By the way, the string is ALWAYS converted to a DECIMAL number.
I just have ended my code which allow to cover your password. It goes like this(FASM):
org 100h
mov cx, 16
petla:
mov ah,08h
int 21h
cmp al,0dh
je OK
mov ah,02h
mov dl,42
int 21h
cmp cx,0
je Fail
loop petla
Fail:
mov dl, 0ah
int 21h
mov dx, pass2
mov ah,9
int 21h
jmp koniec
OK:
mov dl, 0ah
int 21h
mov dx, pass
mov ah,9
int 21h
jmp koniec
koniec:
mov ah,4ch
int 21h
pass db 'Password OK', 0Ah, 0Dh, '$'
pass2 db 'Password Fail', 0Ah, 0Dh, '$'
And now I need to print the genuine password. I know the string buffer is a must and how declaration of the buffer should look like but I don't really know how to use it and make it work.
Calling for help :)
Cheers.
Since your program allows the input of 15 characters of password, you could setup the buffer with:
Buffer db 16 dup ("$")
You initialize the DI register before your petla loop and put the ASCII code you got from the DOS function in the buffer via a stosb instruction:
mov di, Buffer
mov cx, 16
petla:
mov ah,08h
int 21h
cmp al,0dh
je OK
stosb
mov ah,02h
mov dl,42
int 21h
;;;cmp cx,0
;;;je Fail
loop petla
Please note that compairing for CX=0 is useless just before the loop instruction in your code.
I am trying to write a program using x86 assembly that can search for a word in a text. When the word is present in the text, the program will inform the user. I'm still having a problem in comparing the strings. Any advice?
.model small
.stack 200h
.data
message1 db "Enter your text here: $"
text db 150,151 dup(0)
message2 db 10,13,"Enter the word that you want to find: $"
find db 20,21 dup(0)
yesmessage db 10,13,"The word is in the text$"
nomessage db 10,13,"Sorry the word is not in the text$"
.code
Start:
;Display message and key in strings
mov ax,seg message1
mov ds,ax
mov si,offset text
mov di,offset find
mov dx,offset message1
mov ah,09h
int 21h
mov dx,si
mov ah,0Ah
int 21h
mov ax,seg message2
mov ds,ax
mov dx,offset message2
mov ah,09h
int 21h
mov dx,di
mov ah,0Ah
int 21h
;compare strings
mov bx,00
mov bl,text+1
mov bh,find+1
cmp bl,bh
jne L1
add si,2
add di,2
L2:mov bl,byte ptr[si]
cmp byte ptr[di],bl
jne L1
inc si
inc di
cmp byte ptr[di],"$"
jne L2
mov ah,09h
mov dx,offset yesmessage
int 21h
L1:mov ah,09h
mov dx,offset nomessage
int 21H
mov ax,4c00h
int 21h
end start
the expected result should be:
Example 1:
Enter your text here: He is old
Enter the word that you want to find: old
The word is in the text
Example 2:
Enter your text here: He is old
Enter the word that you want to find: young
Sorry the word is not in the text
I can see a couple of obvious problems in your code. See my comments below:
mov bx,00 ; this instruction is redundant
mov bl,text+1
mov bh,find+1
cmp bl,bh
jne L1 ; it's quite likely that the strings won't have the same length,
; i.e. that find will be shorter than text. this condition is
; therefore incorrect. it would make more sense to use jl, i.e.
; jumping to the negative print if text is shorter than find.
mov ah,09h
mov dx,offset yesmessage
int 21h
L1:mov ah,09h
mov dx,offset nomessage ; you'll be printing both messages in cases where
int 21H ; the substring is found, because you don't have
; any jump that skips past it.