CODEWITHSUNDEEP
assemblycalculator
JohnnnnnY
JohnnnnnY

Reputation: 35

assembly conversion str to int

I'm doing a little practice in assembly, using 8086 TASM, and i've encountered a problem I'm trying to solve for some time now. The main program, a basic calculator to add, and substract big numbers. I reached the point to store the user input, and tried to substract 48 from it, to be a real decimal number. The problem is it's writing out smileys and poker symbols instead of actual numbers. Here's the code of the reading and printing:

READNUM PROC
PUSH SI
MOV CX, 0
READ:
MOV AH, 1h 
INT 21h
CMP CX, 9
JE ENDREAD
CMP AL, 0dh
JE ENDREAD
SUB AL, 48d
MOV [SI], AL
INC CX
INC SI
JMP READ
ENDREAD:
MOV byte ptr [SI], 0
MOV AX, 0e0ah 
INT 10h
POP SI
CALL PRINTER
RET
READNUM ENDP


PRINTER PROC              
CYCLE:
LODSB               
CMP     AL, 0       
JE      OVER         
MOV     AH, 14     
INT     10H          
JMP     CYCLE         
VER:
RET                 
PRINTER ENDP

Upvotes: 0

Views: 197

Answers (2)

Michael
Michael

Reputation: 58467

You convert the digits from characters to values when you subtract 48 (e.g. '0' -> 0). When you want to print the digits to the screen you need to convert them back to characters by adding 48 again.

Upvotes: 2

JohnnnnnY
JohnnnnnY

Reputation: 35

In the mean time I've found what was missing. I forgot to add 30h to al. just like this before sub:

...
ADD AL, 30h
SUB AL, 48d
...

Upvotes: 0

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