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Mr.Barbo
Asked: 2020-07-07 18:09:51 +0800 CST 2020-07-07 18:09:51 +0800 CST

mov instruction in assembly language

  • 772

I'm on linux with nasm trying to move registry value axto registry eaxlike this:

mov ebx,1
mov ax,2
mov ecx,ax

but I get the error: prueba.asm:12: error: invalid combination of opcode and operandsand I want to know what exactly is wrong.

ensamblador

1 Answers

  1. Best Answer

    The error is due to the fact that it is not possible to move an AX record that contains divisions, that is (AH and AL) , to an extended record of 32 such as ECX that does not contain a subdivision as AX does , since naturally we always worked with records from 8 moved to registers of 16, for example:

    mov bl,10001111b
movzx ax,bl

    As a solution you could perform the following operations:

        mov ebx,1
    mov eax,2
    MOV ecx,eax
//-------------------
    mov ebx,1
    mov ax,2
    MOV cx,ax
//------------------
    mov ebx,1
    mov ax,2
    MOV ecx,eax
    • 4