Hi,
Can you please explain what the following program does?
Code:Execution begins at address 0 .pos 0 init: irmovl Stack, %esp # Set up Stack pointer irmovl Stack, %ebp # Set up base pointer jmp Main # Execute main program # Array of 4 elements .align 4 array: .long 0xd .long 0xc0 .long 0xb00 .long 0xa000 Main: irmovl $4,%eax pushl %eax # Push 4 irmovl array,%edx pushl %edx # Push array call rSum # Sum(array, 4) halt /* $begin rsum-ys */ # int Sum(int *Start, int Count) rSum: pushl %ebp rrmovl %esp,%ebp pushl %ebx # Save value of %ebx mrmovl 8(%ebp),%ebx # Get Start mrmovl 12(%ebp),%eax # Get Count andl %eax,%eax # Test value of Count jle L38 # If <= 0, goto zreturn irmovl $-1,%edx addl %edx,%eax # Count-- pushl %eax # Push Count irmovl $4,%edx rrmovl %ebx,%eax addl %edx,%eax pushl %eax # Push Start+1 call rSum # Sum(Start+1, Count-1) mrmovl (%ebx),%edx addl %edx,%eax # Add *Start jmp L39 # goto done L38: xorl %eax,%eax # zreturn: L39: mrmovl -4(%ebp),%ebx # done: Restore %ebx rrmovl %ebp,%esp # Deallocate stack frame popl %ebp # Restore %ebp ret /* $end rsum-ys */ .pos 0x400 Stack: # The stack goes here
