loops and loops and 32bit reg

[skinnyg]

Ok.. i am in class.. 2 weeks left.. and i am stuck like chuck...so i call the pros...What i am triing to do is get user to input a word or phrase which is then encrypted.. i dont know what i am missing..last programing class ever.. :D.. def will leave to the pros... code below..

Include Irvine32.inc


.data

key BYTE -2,4,1,0,-3,5,2,-4,-4,6
keySize = $ - key      
plaintext BYTE 21 DUP(0) ;input buffer
textCount DWORD ? ; holds counter
userinput BYTE "Please type in a word to encrypt  : ",0
outputword BYTE "Your word encrpyted  : ",0

.code

main PROC

mov edx,OFFSET plaintext ; point to the buffer
mov ecx,SIZEOF textcount ; specify max characters
mov ebx, userinput
call Write String
call ReadString ; input the string
mov textcount,eax ; number of characters


;call clrscr
;call writestring

mov esi, OFFSET plainText

L1:


   mov edi, OFFSET key
   mov ecx, keySize
   Call Encode
   jnz L1


   mov edx, OFFSET plainText
   call WriteString
   call Crlf

exit

MAIN ENDP

Encode PROC



L1:

   push ecx
   cmp BYTE PTR[esi],0
   je L4

   mov cl,[edi]
   cmp cl,0   ;rotate right
   jge L2      ;if yes goto L2
   neg cl
   rol BYTE PTR[esi], cl   ;rotate lft
   jmp L3

L2:

   ror BYTE PTR[esi], cl ;rotate rgt

L3:

   inc esi      ;nxt letter
   inc edi      ;nxt key



   pop ecx
   loop L1
   or eax, 1 ;force ZF=0
   jmp L5

L4:

   pop ecx ; return zf=1

L5:


ret

ENCODE ENDP

END Main

[MichaelW]

mov ebx, userinput ; error A2070: invalid instruction operands

The problem is that userinput is defined as a BYTE, but EBX is a DWORD register.
The statement should probably be:
mov ebx, OFFSET userinput
call Write String ; Error A2206: missing operator in expression
"Write String" should be one word.

And there are other errors.

[xandaz]

All compiles good buddy. Just tweak those extern symbols i put.

Code Select Expand


;Include \masm32\include\Irvine32.inc
.586
.model flat,stdcall
option casemap:none

.data

extern       Write_String:NEAR
extern       ReadString:NEAR
extern       Crlf:NEAR
key BYTE -2,4,1,0,-3,5,2,-4,-4,6
keySize = $ - key       
plaintext BYTE 21 DUP(0) ;input buffer
textcount DWORD ? ; holds counter
userinput BYTE "Please type in a word to encrypt  : ",0
outputword BYTE "Your word encrpyted  : ",0

.code

main PROC

mov edx,OFFSET plaintext ; point to the buffer
mov ecx,SIZEOF textcount ; specify max characters
mov ebx,offset userinput
call Write_String
call ReadString ; input the string
mov dword ptr textcount,eax ; number of characters


;call clrscr
;call writestring

mov esi, OFFSET plaintext

L1:


   mov edi, OFFSET key
   mov ecx, keySize
   Call Encode
   jnz L1


   mov edx, OFFSET plaintext
   call Write_String
   call Crlf

;exit

main ENDP

Encode PROC



L1:

   push ecx
   cmp BYTE PTR[esi],0
   je L4

   mov cl,[edi]
   cmp cl,0   ;rotate right
   jge L2      ;if yes goto L2
   neg cl
   rol BYTE PTR[esi], cl   ;rotate lft
   jmp L3

L2:

   ror BYTE PTR[esi], cl ;rotate rgt

L3:

   inc esi      ;nxt letter
   inc edi      ;nxt key



   pop ecx
   loop L1
   or eax, 1 ;force ZF=0
   jmp L5

L4:

   pop ecx ; return zf=1

L5:


ret

Encode ENDP

END main
regs X

[skinnyg]

Thanks alot.. this really helped..still racked my brain..  :t