Reading a BYTE array into a DWORD array with a loop

Question

This is a question identical to previous post. The objective is to take a BYTE array of 2, 4, 6, 8 ,10 and insert them into a DWORD array via a LOOP to display them. This is my latest attempt.

INCLUDE Irvine32.inc

.data

Array1 BYTE 2,4,6,8,10
Array2 DWORD 5 dup(0)

.code
main PROC


 mov esi, OFFSET Array1  ;esi = byteArray
 mov edi, OFFSET Array2  ;edi = dwordArray
 mov ecx, 5              ;counter of loop


 DAWG:
     mov eax, [esi]   ;attempting to use movzx causes errors
     mov [edi], eax
     inc esi
     add edi, 4
     loop DAWG

Any suggestions? Trying to figure it out with my bit (pun intended) of assembly knowledge. Thanks for reading.

It indeed does. Thanks! For my knowledge, why does `byte ptr` make the statement work? — caboose103, Sep 26 '15 at 18:57
The assembler has to know, how much of [esi] is to be loaded into `EAX`, since there are different machine instructions for that purpose. `byte ptr` means: take one byte. — rkhb, Sep 26 '15 at 19:02

score 3 · Accepted Answer · answered Sep 27 '15 at 19:13

3

1st solution as suggested by @rkhb is

DAWG:
 movzx eax, byte ptr [esi]
 mov   [edi], eax
 inc   esi
 add   edi, 4
 loop  DAWG

I would like to add this slightly more elegant solution:

 cld
 xor   eax, eax
DAWG:
 lodsb
 stosd
 loop  DAWG

answered Sep 27 '15 at 19:13

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Reading a BYTE array into a DWORD array with a loop

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