Question

Look a asm code sample below INCLUDE Irvine32.inc .data array DWORD 5,4,3,2,1 .code main PROC mov esi, OFFSET array call DumpRegs mov eax, (esi] call DumpRegs exit main ENDP END main What value will be in the al register?

Answer 1

The AL register will contain the value '5', which is the least significant byte of the EAX register after the instruction mov eax, [esi] assuming correct syntax is used in the assembly code example provided.

Step-by-step explanation:

The student is asking about the value that will be in the AL register after the execution of a particular segment of assembly code which involves the Irvine32.inc library. The code loads the address of the first element of an array into the ESI register and then attempts to move the value at the address pointed to by ESI into the EAX register. However, there is a typo in the instruction mov eax, (esi]. If we assume that the correct syntax was intended (which should be mov eax, [esi]), the value at the memory location pointed by ESI would be transferred to EAX.

Since ESI points to the beginning of the array, which is 5,4,3,2,1, and EAX is a 32-bit register, the entire value '5' (which is the first element of the array) will be moved into EAX. The AL register is the lower 8-bits of the EAX register, meaning it will contain the least significant byte of the value in EAX. Since 5 is within a byte's range, AL would also contain the value '5'.