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Theo



Joined: 19 Mar 2005
Posts: 7
Theo
how to parse the decimal number inputed from keyboard (ASCII code) into binary code and parse the binary code to decimal number?

i just want to get 2 numbers from keyboard and show the sum of them.
Post 31 Mar 2005, 23:13
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r22



Joined: 27 Dec 2004
Posts: 805
r22
That's kind of a pain in the butt to do in ASM.
BIN -> ASCII representation can be done using the wsprintf function
But ASCII -> BIN I don't think there's a descent function for that.

Code:
;This will only work for 32bit unsigned integers 0-4294967295
ASC2BIN_Integer:
.strNum equ ebp+8
push ebp
mov ebp,esp
  xor eax, eax
  mov esi, [.strNum] ;ptr to null terminated ASCII number ie'123',0
 .Next:
  movzx ecx, byte [esi]
  xor ecx, 30h 
;subtract 48 from ascii '0' = 48 - 48 = 0, '9' = 57 -4 8 = 9
  add esi,1 
  mov edx, 10
  mul edx ;multiply EAX by 16 (first pass it does nothing)
  add eax, ecx
  cmp byte [esi], 0 ;if null there's no more chars in string so done
  je .done
  jmp .Next
 .done:
mov esp,ebp
pop ebp
retn 4
    


numb db '100',0
push numb
call ASC2BIN_Integer
;EAX = 64h
Post 01 Apr 2005, 03:13
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r22



Joined: 27 Dec 2004
Posts: 805
r22
my comment was flawed

" mul edx ;multiply EAX by 16 (first pass it does nothing) "
I meant <<10>> not <<16>>
Post 02 Apr 2005, 02:53
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