Having problems with .while Cnt < 32

[hfheatherfox07]

Hello,
I need to change  .while Cnt < 32
To  .while Cnt < Buffervaluesize
How do I do that?
Thank you !

Here is what I am working on :
Read REG_BINARY Key Value:

Code Select Expand

; Read a REG_BINARY Key Value in Hex
.386
.model flat, stdcall
option casemap: none

include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
include \masm32\include\advapi32.inc  ; Needed to support the registry API's
include \masm32\include\masm32.inc

includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\advapi32.lib ; Needed to support the registry API's
includelib \masm32\lib\masm32.lib

ReadRegistry PROTO

.data
sPIdKey     db "SOFTWARE\RandomTestKey\Test key", 0 ; // handle of key adress
keyread db "REG_BINARY Key Read...",0 ;  MessageBox Caption
sPIdValue   db "TestValue", 0 ; // address of name of value to query
szSpace     db " ",0
format      db "%X",0; Cpital X Is Captital Letters, Small x is small Letters

; Read Key Error
szError     db "Could Not read Key!",0
szErrorCapt db "Sorry",0

.data?
hkKey      HKEY ? ; // handle of key to query
;dwKeySize DWORD ? ; // address of data buffer size
szBuff   dd  1024 dup(?) ; // address of Hexadecimal Value buffer
szBuff1  dd  1024 dup(?) ; // address of Decimal Value buffer
szBuff2  dd  1024 dup(?)
dwValueType   dd  ? ; // address of buffer for value type
dwKeySize dd ?
Cnt dd ?
;---------------------------------------------------------------------------
.code
start:

INVOKE ReadRegistry

ReadRegistry proc

;LOCAL    Cnt:DWORD
;open or create a new key
; Gets the PId
    INVOKE RegOpenKeyEx, HKEY_CURRENT_USER,  addr sPIdKey, 0, KEY_WRITE or KEY_READ,  addr hkKey
    mov dwKeySize, sizeof szBuff; Or mov dwKeySize, sizeof szFinalBuffer
    INVOKE RegQueryValueEx, hkKey,  addr sPIdValue, NULL,  addr dwValueType,  addr szBuff ,  addr dwKeySize
    ; If Key exsists
  .IF eax == ERROR_SUCCESS ; Same as  .IF eax !=1

   mov     byte ptr szBuff2, 0
            and     Cnt, 0
         .while Cnt < 32
               xor     edx, edx
               mov     eax, Cnt
               mov     dl, byte ptr szBuff[eax]
            INVOKE     wsprintf, addr szBuff1, addr format, edx
            INVOKE     lstrcat, addr szBuff2, addr szBuff1
            .if al!=0 ; We look if the last
               INVOKE     lstrcat, addr szBuff2, addr szSpace
            .endif
               inc     Cnt
 
         .endw

             INVOKE MessageBox, 0,  addr szBuff2 , addr keyread, MB_OK ; Display the value   
   
     
    INVOKE RegCloseKey, hkKey ; Close the registry key
   
   jmp exit
   ret
  .ELSE
  INVOKE MessageBox, NULL, addr szError, addr szErrorCapt, MB_ICONEXCLAMATION ;call our Messagbox
jmp exit
.ENDIF
exit:
  INVOKE ExitProcess,0
  xor eax,eax
ret

ReadRegistry endp

end start

If you want to test the above , You can write that registry Key With this:

Code Select Expand

; Create NEW registry key + REG_BINARY Value
.386
.model flat, stdcall
option casemap: none

include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
include \masm32\include\advapi32.inc  ; Needed to support the registry API's

includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\advapi32.lib ; Needed to support the registry API's

SaveRegistry PROTO

.data
szRegInfo       db "SOFTWARE\RandomTestKey\Test key", 0
szRegValue      db "TestValue",0
szRegValueData  db 48h,65h,6Ch,6Ch,6Fh,20h,57h,6Fh,72h,6Ch,64h
; You can write the value as a string and It will be converted any ways! szRegValueData  db "Hello World",0
; But it adds 2 extra zeros at the end and a "." !!!
;Hello World = 48 65 6C 6C 6F 20 57 6F 72 6C 64
; ***NOTE:***
;  dd 48h,65h,6Ch,6Ch,6Fh,20h,57h,6Fh,72h,6Ch,64h  Will Write 6 extra zeros-So: 48 00 00 00 65 00 00 00 ETC...
;  dw 48h,65h,6Ch,6Ch,6Fh,20h,57h,6Fh,72h,6Ch,64h  Will Write 2 extra zeros-So: 48 00 65 00 ETC...

szSuccess    db "REG Key Was Created",0 ;  MessageBox Message
szSuccessCpt db "Reg key...",0     ;  MessageBox Title
; Writr Key Error
szError     db "Could Not Write Key!",0
szErrorCapt db "Sorry",0
.data?
hkKey    HKEY  ?
szlpData  dd ?
;---------------------------------------------------------------------------
.code
start:
INVOKE SaveRegistry

SaveRegistry proc


;open or create a new key
   INVOKE RegCreateKey, HKEY_CURRENT_USER, ADDR szRegInfo,  ADDR hkKey
; Add an entry into the registry to remember that the file has already been created

   mov    szlpData,sizeof szRegValueData
; you can have REG_SZ ,REG_DWORD, REG_BINARY ,REG_NONE , REG_EXPAND_SZ,REG_LINK,REG_RESOURCE_LIST,REG_DWORD_LITTLE_ENDIAN,REG_DWORD_BIG_ENDIAN,REG_MULTI_SZ
   INVOKE RegSetValueEx, hkKey,ADDR szRegValue,NULL, REG_BINARY , ADDR szRegValueData,szlpData
   INVOKE RegCloseKey, hkKey ; Close the key
    ; If Key Created
  .IF eax == ERROR_SUCCESS ; Same as  .IF eax !=1
    INVOKE MessageBox, NULL, ADDR szSuccess, addr szSuccessCpt, MB_ICONINFORMATION ; Display a success Message
  jmp exit
   ret
  .ELSE
  INVOKE MessageBox, NULL, addr szError, addr szErrorCapt, MB_ICONEXCLAMATION ;call our Messagbox
jmp exit
.ENDIF
exit:
  INVOKE ExitProcess,NULL
  xor eax,eax
ret

SaveRegistry endp

end start

[dedndave]

you can't compare one memory operand to another memory operand that way
put one of the values in a register
in this case, it's nice to have Cnt in a register because it's used inside the loop
EBX needs to be preserved across calls
and - it is preserved across API calls - no need to push/pop inside the loop

Code Select Expand

        push    ebx
        xor     ebx,ebx
        .while ebx < Buffervaluesize
            movzx   edx, byte ptr szBuff[ebx]
            INVOKE  wsprintf, addr szBuff1, addr format, edx
            INVOKE  lstrcat, addr szBuff2, addr szBuff1
            .if al!=0                                         ; We look if the last
                INVOKE  lstrcat, addr szBuff2, addr szSpace
            .endif
            inc     ebx
        .endw
        pop     ebx

[qWord]

an ugly trick for two memory operands:

Code Select Expand

mov eax,mem1
.while mem2 < eax
    ;...
    mov eax,mem1
.endw

[hfheatherfox07]

Thank you all   
@qWord that's going to come in handy!
I like that trick  :t

[hfheatherfox07]

an ugly trick for two memory operands:

Code Select Expand

mov eax,mem1
.while mem2 < eax
    ;...
    mov eax,mem1
.endw

@ qWord
How did you intend this to work in this situation?

Code Select Expand

; Read a REG_BINARY Key Value in Hex
.386
.model flat, stdcall
option casemap: none

include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
include \masm32\include\advapi32.inc  ; Needed to support the registry API's
include \masm32\include\masm32.inc

includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\advapi32.lib ; Needed to support the registry API's
includelib \masm32\lib\masm32.lib

ReadRegistry PROTO

.data
sPIdKey     db "SOFTWARE\RandomTestKey\Test key", 0 ; // handle of key adress
keyread db "REG_BINARY Key Read...",0 ;  MessageBox Caption
sPIdValue   db "TestValue", 0 ; // address of name of value to query
szSpace     db " ",0
format      db "%X",0; Cpital X Is Captital Letters, Small x is small Letters

; Read Key Error
szError     db "Could Not read Key!",0
szErrorCapt db "Sorry",0

.data?
hkKey      HKEY ? ; // handle of key to query
;dwKeySize DWORD ? ; // address of data buffer size
szBuff   dd  256 dup(?) ; // address of Hexadecimal Value buffer
szBuff1  dd  256 dup(?) ; // address of Decimal Value buffer
szBuff2  dd  256 dup(?)
szTempBuffer dd  1024 dup(?)
dwValueType   dd  ? ; // address of buffer for value type
dwKeySize dd ?
Cnt dd ?
;---------------------------------------------------------------------------
.code
start:

INVOKE ReadRegistry

ReadRegistry proc


;open or create a new key
; Gets the PId
    INVOKE RegOpenKeyEx, HKEY_CURRENT_USER,  addr sPIdKey, 0, KEY_WRITE or KEY_READ,  addr hkKey
    mov dwKeySize, sizeof szBuff
    INVOKE RegQueryValueEx, hkKey,  addr sPIdValue, NULL,  addr dwValueType,  addr szBuff ,  addr dwKeySize
    ; If Key exsists
  .IF eax == ERROR_SUCCESS ; Same as  .IF eax !=1
 
       mov eax,szBuff ; Moves our value into eax

        .while szTempBuffer < eax
               xor     edx, edx
               mov     eax, Cnt
               mov     dl, byte ptr szBuff[eax]
       
            INVOKE     wsprintf, addr szBuff1, addr format, edx
            INVOKE     lstrcat, addr szBuff2, addr szBuff1
             .if al!=0 
               INVOKE    lstrcat, addr szBuff2, addr szSpace
            .endif
               inc     Cnt
 
         .endw


             INVOKE MessageBox, 0,  addr szBuff2 , addr keyread, MB_OK ; Display the value   
   
     
    INVOKE RegCloseKey, hkKey ; Close the registry key
   
   jmp exit
   ret
  .ELSE
  INVOKE MessageBox, NULL, addr szError, addr szErrorCapt, MB_ICONEXCLAMATION ;call our Messagbox
jmp exit
.ENDIF
exit:
  INVOKE ExitProcess,0
  xor eax,eax
ret

ReadRegistry endp

end start

[hfheatherfox07]

Here is another working version :t
In Case some one needs to read REG_BINARY Registry Key

Code Select Expand

; Read a REG_BINARY Key Value in Hex
.386
.model flat, stdcall
option casemap: none

include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
include \masm32\include\advapi32.inc  ; Needed to support the registry API's
include \masm32\include\masm32.inc

includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\advapi32.lib ; Needed to support the registry API's
includelib \masm32\lib\masm32.lib

ReadRegistry PROTO

.data
sPIdKey     db "SOFTWARE\RandomTestKey\Test key", 0 ; // handle of key adress
keyread db "REG_BINARY Key Read...",0 ;  MessageBox Caption
sPIdValue   db "TestValue", 0 ; // address of name of value to query
szSpace     db " ",0
format      db "%X",0; Cpital X Is Captital Letters, Small x is small Letters

; Read Key Error
szError     db "Could Not read Key!",0
szErrorCapt db "Sorry",0

.data?
hkKey      HKEY ? ; // handle of key to query
;dwKeySize DWORD ? ; // address of data buffer size
szBuff   dd  1024 dup(?) ; // address of Hexadecimal Value buffer
szBuff1  dd  1024 dup(?) ; // address of Decimal Value buffer
szBuff2  dd  1024 dup(?)
dwValueType   dd  ? ; // address of buffer for value type
dwKeySize dd ?

;---------------------------------------------------------------------------
.code
start:

INVOKE ReadRegistry

ReadRegistry proc


;open or create a new key
; Gets the PId
    INVOKE RegOpenKeyEx, HKEY_CURRENT_USER,  addr sPIdKey, 0, KEY_WRITE or KEY_READ,  addr hkKey
    mov dwKeySize, sizeof szBuff; Or mov dwKeySize, sizeof szFinalBuffer
    INVOKE RegQueryValueEx, hkKey,  addr sPIdValue, NULL,  addr dwValueType,  addr szBuff ,  addr dwKeySize
    ; If Key exsists
  .IF eax == ERROR_SUCCESS ; Same as  .IF eax !=1

       push    ebx     ; push ebx, this register needs to be saved
        xor     ebx,ebx ; clear ebx register
        .while ebx < dwKeySize ; compare count (ebx) to sizeof szBuff We moved (mov dwKeySize, sizeof szBuff) So we can read the Key
            movzx   edx, byte ptr szBuff[ebx]
            INVOKE  wsprintf, addr szBuff1, addr format, edx  ; Format Result in edx
            INVOKE  lstrcat, addr szBuff2, addr szBuff1       ; Copy szBuff1 to szBuff2
            .if al!=0                                         ; We look if the last Value, If we did
                INVOKE  lstrcat, addr szBuff2, addr szSpace   ; add space To it in szBuff2
            .endif
            inc     ebx ; Increase counter
        .endw
        pop     ebx ; pop ebx off the stack again

             INVOKE MessageBox, 0,  addr szBuff2 , addr keyread, MB_OK ; Display the value   
   
     
    INVOKE RegCloseKey, hkKey ; Close the registry key
   
   jmp exit
   ret
  .ELSE
  INVOKE MessageBox, NULL, addr szError, addr szErrorCapt, MB_ICONEXCLAMATION ;call our Messagbox
jmp exit
.ENDIF
exit:
  INVOKE ExitProcess,0
  xor eax,eax
ret

ReadRegistry endp

end start

[dedndave]

Code Select Expand

  .IF eax == ERROR_SUCCESS ; Same as  .IF eax !=1

   mov     byte ptr szBuff2, 0

did you forget this line - or not need it ?

[hfheatherfox07]

Not needed ? I get the same result with or with out

[dedndave]

yah - it doesn't look like it's needed if ERROR_SUCCESS

but - it might be nice to set it to null if there is an error

Code Select Expand

  .IF eax == ERROR_SUCCESS ; Same as  .IF eax !=1

;do stuff

  .ELSE
  mov byte ptr szBuff2,0
  INVOKE MessageBox, NULL, addr szError, addr szErrorCapt, MB_ICONEXCLAMATION ;call our Messagbox
.ENDIF

i just noticed - the "jmp exit" lines
neither of those are needed because execution continues at "exit" after the if/else/endif
also - the word "exit" is the name of a macro
you will get error messages if you try to include macros.asm

[jj2007]

.While 1
  mov eax, mem1
  .Break .if mem2>eax  ; or whatever
  ...
.Endw

.Repeat
  ...
    mov eax, mem1
.Until mem2>eax  ; or whatever

Note that .Repeat ... .Until is a bit faster and shorter than .While - if you are sure that the loop must be taken at least once, use .Repeat.

[dedndave]

i think registry value data can have null length

[hfheatherfox07]

I am getting the same result either way ... same as the other one ...too many extra zeros  :(
May be the ugly trick does not work in this case  :(

[hfheatherfox07]

@ qWord
I Got It  :t
I forgot to take into account that I moved  the size of result of key read , with  "mov dwKeySize, sizeof szBuff"
So we have to compare Cnt to eax after we move that into eax  "mov eax,dwKeySize"

Here is another working example :

Code Select Expand

; Read a REG_BINARY Key Value in Hex
.386
.model flat, stdcall
option casemap: none

include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
include \masm32\include\advapi32.inc  ; Needed to support the registry API's
include \masm32\include\masm32.inc

includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\advapi32.lib ; Needed to support the registry API's
includelib \masm32\lib\masm32.lib

ReadRegistry PROTO

.data
sPIdKey     db "SOFTWARE\RandomTestKey\Test key", 0 ; // handle of key adress
keyread db "REG_BINARY Key Read...",0 ;  MessageBox Caption
sPIdValue   db "TestValue", 0 ; // address of name of value to query
szSpace     db " ",0
format      db "%X",0; Cpital X Is Captital Letters, Small x is small Letters

; Read Key Error
szError     db "Could Not read Key!",0
szErrorCapt db "Sorry",0

.data?
hkKey      HKEY ? ; // handle of key to query
;dwKeySize DWORD ? ; // address of data buffer size
szBuff   dd  256 dup(?) ; // address of Hexadecimal Value buffer
szBuff1  dd  256 dup(?) ; // address of Decimal Value buffer
szBuff2  dd  256 dup(?)
szTempBuffer dd  1024 dup(?)
dwValueType   dd  ? ; // address of buffer for value type
dwKeySize dd ?
Cnt dd ?
;---------------------------------------------------------------------------
.code
start:

INVOKE ReadRegistry

ReadRegistry proc


;open or create a new key
; Gets the PId
    INVOKE RegOpenKeyEx, HKEY_CURRENT_USER,  addr sPIdKey, 0, KEY_WRITE or KEY_READ,  addr hkKey
    mov dwKeySize, sizeof szBuff
    INVOKE RegQueryValueEx, hkKey,  addr sPIdValue, NULL,  addr dwValueType,  addr szBuff ,  addr dwKeySize
    ; If Key exsists
  .IF eax == ERROR_SUCCESS ; Same as  .IF eax !=1
 
       mov eax,dwKeySize ; We moves our dwKeySize value into eax To compare count  Since  We moved (mov dwKeySize, sizeof szBuff) So we can read the Key

        .while Cnt < eax
               xor     edx, edx
               mov     eax, Cnt
               mov     dl, byte ptr szBuff[eax]
       
            INVOKE     wsprintf, addr szBuff1, addr format, edx
            INVOKE     lstrcat, addr szBuff2, addr szBuff1
             .if al!=0 
               INVOKE    lstrcat, addr szBuff2, addr szSpace
            .endif
               inc     Cnt
   mov eax,dwKeySize
         .endw


             INVOKE MessageBox, 0,  addr szBuff2 , addr keyread, MB_OK ; Display the value   
   
     
    INVOKE RegCloseKey, hkKey ; Close the registry key
   
   jmp exit
   ret
  .ELSE
  INVOKE MessageBox, NULL, addr szError, addr szErrorCapt, MB_ICONEXCLAMATION ;call our Messagbox
jmp exit
.ENDIF
exit:
  INVOKE ExitProcess,0
  xor eax,eax
ret

ReadRegistry endp

end start

[hfheatherfox07]

.While 1
  mov eax, mem1
  .Break .if mem2>eax  ; or whatever
  ...
.Endw

.Repeat
  ...
    mov eax, mem1
.Until mem2>eax  ; or whatever

Note that .Repeat ... .Until is a bit faster and shorter than .While - if you are sure that the loop must be taken at least once, use .Repeat.

:t

Here is an example using .Repeat and .Until 

Code Select Expand

; Read a REG_BINARY Key Value in Hex
.386
.model flat, stdcall
option casemap: none

include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
include \masm32\include\advapi32.inc  ; Needed to support the registry API's
include \masm32\include\masm32.inc

includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\advapi32.lib ; Needed to support the registry API's
includelib \masm32\lib\masm32.lib

ReadRegistry PROTO

.data
sPIdKey     db "SOFTWARE\RandomTestKey\Test key", 0 ; // handle of key adress
keyread db "REG_BINARY Key Read...",0 ;  MessageBox Caption
sPIdValue   db "TestValue", 0 ; // address of name of value to query
szSpace     db " ",0
format      db "%X",0; Cpital X Is Captital Letters, Small x is small Letters

; Read Key Error
szError     db "Could Not read Key!",0
szErrorCapt db "Sorry",0

.data?
hkKey      HKEY ? ; // handle of key to query
;dwKeySize DWORD ? ; // address of data buffer size
szBuff   dd  256 dup(?) ; // address of Hexadecimal Value buffer
szBuff1  dd  256 dup(?) ; // address of Decimal Value buffer
szBuff2  dd  256 dup(?)
szTempBuffer dd  1024 dup(?)
dwValueType   dd  ? ; // address of buffer for value type
dwKeySize dd ?
Cnt dd ?
;---------------------------------------------------------------------------
.code
start:

INVOKE ReadRegistry

ReadRegistry proc


;open or create a new key
; Gets the PId
    INVOKE RegOpenKeyEx, HKEY_CURRENT_USER,  addr sPIdKey, 0, KEY_WRITE or KEY_READ,  addr hkKey
    mov dwKeySize, sizeof szBuff
    INVOKE RegQueryValueEx, hkKey,  addr sPIdValue, NULL,  addr dwValueType,  addr szBuff ,  addr dwKeySize
    ; If Key exsists
  .IF eax == ERROR_SUCCESS ; Same as  .IF eax !=1
 
   
.Repeat
               xor     edx, edx ; clear rd register
               mov     eax, Cnt ; move Count to eax
               mov     dl, byte ptr szBuff[eax]
       
            INVOKE     wsprintf, addr szBuff1, addr format, edx ; Format result in szBuff1
            INVOKE     lstrcat, addr szBuff2, addr szBuff1      ; Copy szBuff1 to szBuff2
             .if al!=0  ; If We look if the last character
               INVOKE    lstrcat, addr szBuff2, addr szSpace    ; Add a space
            .endif
               inc     Cnt  ; Increase counter
   mov eax,dwKeySize  ;  mov eax,dwKeySize ; We moves our dwKeySize value into eax To compare count  Since  We moved (mov dwKeySize, sizeof szBuff) So we can read the Key
.Until Cnt==eax


             INVOKE MessageBox, 0,  addr szBuff2 , addr keyread, MB_OK ; Display the value   
   
     
    INVOKE RegCloseKey, hkKey ; Close the registry key
   
   jmp exit
   ret
  .ELSE
  INVOKE MessageBox, NULL, addr szError, addr szErrorCapt, MB_ICONEXCLAMATION ;call our Messagbox
jmp exit
.ENDIF
exit:
  INVOKE ExitProcess,0
  xor eax,eax
ret

ReadRegistry endp

end start

[jj2007]

               xor     edx, edx ; clear rd register
               mov     eax, Cnt ; move Count to eax
               mov     dl, byte ptr szBuff[eax]

better:
               mov     eax, Cnt ; move Count to eax
               movzx     edx, byte ptr szBuff[eax]
in case you want signed values:
               xor     edx, edx ; clear rd register
               mov     eax, Cnt ; move Count to eax
               movsx     edx, byte ptr szBuff[eax]