can someone help explain each step of the assembly language code using variables

Question

can someone help explain each step of the assembly language code using variables h, t and len.

loop:
pushl %ebp
movl %esp,%ebp
movl 0x8(%ebp),%edx
movl %edx.%eax
addl 0xc(%ebp),%eax
leal 0xffffffff(%eax),%ecx
cmpl %ecx,%edx
jae .L4
.L6:
movb (%edx),%al
xorb (%ecx),%al
movb %al,(%edx)
xorb (%ecx),%al
movb %al,(%ecx)
xorb %al,(%edx)
incl %edx
decl %ecx
cmpl %ecx,%edx
jb .L6
.L4:
movl %ebp,%esp
popl %ebp
ret




Thank you life saver!!!!

Explanation / Answer

loop: pushl %ebp movl %esp,%ebp movl 0x8(%ebp),%edx # h movl %edx,%eax # h addl 0xc(%ebp),%eax # h + len leal 0xffffffff(%eax),%ecx # t = h + len - 1 cmpl %ecx,%edx # if h >= t jae .L4 # finshed .L6: movb (%edx),%al # *h xorb (%ecx),%al # *t ^ *h movb %al,(%edx) # *h = *t ^ *h xorb (%ecx),%al # *t ^ *h movb %al,(%ecx) # *t = *t ^ *h xorb %al,(%edx) # *h = *t ^ *h incl %edx # h++ decl %ecx # t-- cmpl %ecx,%edx # if h

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