Question

Convert this C++ program exactly as you see it into x86 assembly language:

// Use the Irvine library for the print function

#include <iostream>

// The string that needs to be printed

char word[] = "Golf\0";

// Pointer to a specific character in the string

char * character = word;

//NOTE: This main() function is not portable outside of Visual Studio

void main()

{

// Set up a LOOP - See the while loop's conditional expression below

int ecx = 4;

do

{

// Print the character

// In x86 assembly language you must use the following two lines of code:

// mov al, WHATEVER_CHARACTER_YOU_WANT_TO_PRINT

// call WriteChar

std::cout << *character;

// Increment the pointer

++character;

} while (--ecx != 0);

// In x86 assembly language you must use the following line of code:

// call CrLf

std::cout << std::endl;

// In x86 assembly language you must use the following line of code:

// call WaitMsg system("PAUSE");

}

Answer 1

Here is the conversion of the C program into X86 assembly language

std::ostream::operator<<(std::ostream& (*)(std::ostream&))@plt:
 jmp    QWORD PTR [rip+0x2fd2]        # 404028 <std::ostream::operator<<(std::ostream& (*)(std::ostream&))@GLIBCXX_3.4>
 push   0x2
 jmp    401020 <.plt>
 jmp    QWORD PTR [rip+0x2fca]        # 404030 <std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char)@GLIBCXX_3.4>
 push   0x3
 jmp    401020 <.plt>
std::ios_base::Init::Init()@plt:
 jmp    QWORD PTR [rip+0x2fc2]        # 404038 <std::ios_base::Init::Init()@GLIBCXX_3.4>
 push   0x4
 jmp    401020 <.plt>
std::ios_base::Init::~Init()@plt:
 jmp    QWORD PTR [rip+0x2fba]        # 404040 <std::ios_base::Init::~Init()@GLIBCXX_3.4>
 push   0x5
 jmp    401020 <.plt>
main:
 push   rbp
 mov    rbp,rsp
 sub    rsp,0x10
 mov    DWORD PTR [rbp-0x4],0x4
 mov    rax,QWORD PTR [rip+0x2ed8]        # 404060 <character>
 movzx  eax,BYTE PTR [rax]
 movsx  eax,al
 mov    esi,eax
 mov    edi,0x404080
 call   401060 <std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char)@plt>
 mov    rax,QWORD PTR [rip+0x2ebf]        # 404060 <character>
 add    rax,0x1
 mov    QWORD PTR [rip+0x2eb4],rax        # 404060 <character>
 sub    DWORD PTR [rbp-0x4],0x1
 cmp    DWORD PTR [rbp-0x4],0x0
 setne  al
 test   al,al
 je     4011bd <main+0x4b>
 jmp    401181 <main+0xf>
 mov    esi,0x401030
 mov    edi,0x404080
 call   401050 <std::ostream::operator<<(std::ostream& (*)(std::ostream&))@plt>
 mov    eax,0x0
 leave  
 ret    
_GLOBAL__sub_I_word:
 push   rbp
 mov    rbp,rsp
 mov    esi,0xffff
 mov    edi,0x1
 call   4011d3 <__static_initialization_and_destruction_0(int, int)>
 pop    rbp
 ret    
 nop    WORD PTR cs:[rax+rax*1+0x0]

The output of the code is Golf

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