Trying to learn from the ground up and would appreciate some assistance
making sense of the following:
// void main(){} [1]
.text._Dmain segment
assume CS:.text._Dmain
_Dmain:
push RBP
mov RBP,RSP
xor EAX,EAX
pop RBP
ret
.text._Dmain ends
.cto
// void main(string[] args) {} [2]
.text._Dmain segment
assume CS:.text._Dmain
_Dmain:
push RBP
mov RBP,RSP
sub RSP,010h
xor EAX,EAX
leave
ret
.text._Dm
Both segments of code deal with a minimal D program: the first taking no
arguments and the second taking a string array. Information prior to the
".text_Dmain segment" in both files mirror each other with the exception
of module name differences.
The first difference that jumps out at me is that the ".text._Dmain
segment" in [1] properly terminates with ".text._Dmain ends" like all
other segments in the file up to this point. [2] is improperly: ".text._Dm".
The second is the use of leave in [2]. If I understand correctly, leave
is the exact same as:
mov RBP,RSP
pop RBP
So why do we need to mov RBP, RSP in [2] but not in [1]? I'm thinking
this is because RBP contains the address of args but not sure.
Last is the .cto at the end of [1], what on earth is it and what is it
used for? Why does it not exist in [2]?
Thanks,
Andrew
