Question

Please write in x86 Assembly language on Visual Studio. IRVINE32

Write a program to copy one array of size 24 to another array of size 24 using string instructions. Write 3 versions of this code. One code must copy byte at a time. One code must copy word at a time and one code must copy double word at a time. Cut and paste the array in memory to show your code is working.

Answer 1

For the following solution, I have assumed that the data is stored as in SRC which is the source , array DEST which is the destination array.

1) For the first version, where we need to copy one byte at a time, we use lodsb command whidch loads the memory byte addressed in the destination register, relative to the ES segment register, into the AL register.

CODE:

Lea si, SRC
lea di, DESI

Mov cx,24

X1:lodsb

Stosb

Loop x1

2) For the first version, where we need to copy one byte at a time, we use lodsw command which loads the memory word addressed in the destination register, relative to the ES segment register, into the AX register.

CODE:

Lea si,SRC

Lea di,DEST

Mov cx ,12

X1:lodsw

Stosw

Loopx1

3) For the first version, where we need to copy one byte at a time, we use lodsl which loads the memory double-word addressed in the destination register, relative to the ES segment register, into the EAX register.

CODE:

Lea si,SRC

Lea di, DEST

Mox cx,6

X1:lodsl

Stosl

Loopx1