Assembly Language for Beginners

(Jeff_L) #1

3.18. C++


push OFFSET $SG39512
lea ecx, DWORD PTR _s1$[esp+80]
mov DWORD PTR _s1$[esp+100], 15
mov DWORD PTR _s1$[esp+96], 0
mov BYTE PTR _s1$[esp+80], 0
call ?assign@?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QAEAAV12@PBDI@Z ;⤦
Ç std::basic_string<char,std::char_traits<char>,std::allocator<char> >::assign

push 7
push OFFSET $SG39514
lea ecx, DWORD PTR _s2$[esp+80]
mov DWORD PTR _s2$[esp+100], 15
mov DWORD PTR _s2$[esp+96], 0
mov BYTE PTR _s2$[esp+80], 0
call ?assign@?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QAEAAV12@PBDI@Z ;⤦
Ç std::basic_string<char,std::char_traits<char>,std::allocator<char> >::assign

lea eax, DWORD PTR _s2$[esp+72]
push eax
lea eax, DWORD PTR _s1$[esp+76]
push eax
lea eax, DWORD PTR _s3$[esp+80]
push eax
call ??$?HDU?$char_traits@D@std@@V?$allocator@D@1@@std@@YA?AV?$basic_string@DU?⤦
Ç$char_traits@D@std@@V?$allocator@D@2@@0@ABV10@0@Z ; std::operator+<char,std::char_traits<⤦
Çchar>,std::allocator<char> >

; inlined c_str() method:
cmp DWORD PTR _s3$[esp+104], 16
lea eax, DWORD PTR _s3$[esp+84]
cmovae eax, DWORD PTR _s3$[esp+84]

push eax
push OFFSET $SG39581
call _printf
add esp, 20

cmp DWORD PTR _s3$[esp+92], 16
jb SHORT $LN119@main
push DWORD PTR _s3$[esp+72]
call ??3@YAXPAX@Z ; operator delete
add esp, 4
$LN119@main:
cmp DWORD PTR _s2$[esp+92], 16
mov DWORD PTR _s3$[esp+92], 15
mov DWORD PTR _s3$[esp+88], 0
mov BYTE PTR _s3$[esp+72], 0
jb SHORT $LN151@main
push DWORD PTR _s2$[esp+72]
call ??3@YAXPAX@Z ; operator delete
add esp, 4
$LN151@main:
cmp DWORD PTR _s1$[esp+92], 16
mov DWORD PTR _s2$[esp+92], 15
mov DWORD PTR _s2$[esp+88], 0
mov BYTE PTR _s2$[esp+72], 0
jb SHORT $LN195@main
push DWORD PTR _s1$[esp+72]
call ??3@YAXPAX@Z ; operator delete
add esp, 4
$LN195@main:
xor eax, eax
add esp, 72
ret 0
_main ENDP


The compiler does not construct strings statically: it would not be possible anyway if the buffer needs to
be located in theheap.


Instead, theASCIIZstrings are stored in the data segment, and later, at runtime, with the help of the

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