Question

Convert this C++ program to x86 assembly language using the Irvine library:

#include <iostream>

unsigned int x;
unsigned int c;
unsigned int result;

// f(x) = 8x + c
// Make sure to push and pop all necessary registers to the stack to
// ensure only the EAX register is modified upon return from the function
unsigned int Equation(unsigned int x, unsigned int c)
{
// You CANNOT use the mul or imul operations to perform the multiplication
return (8 * x) + c;
}

void main()
{
std::cout << "Enter a value for x: ";
std::cin >> x;
std::cout << "Enter a value for c: ";
std::cin >> c;
result = Equation(x, c);
std::cout << "f(x) = " << result << std::endl;
system("PAUSE");
}

Answer 1

x:

        .zero   4

c:

        .zero   4

result:

        .zero   4

Equation(unsigned int, unsigned int):

        push    rbp

        mov     rbp, rsp

        mov     DWORD PTR [rbp-4], edi

        mov     DWORD PTR [rbp-8], esi

        mov     eax, DWORD PTR [rbp-4]

        lea     edx, [0+rax*8]

        mov     eax, DWORD PTR [rbp-8]

        add     eax, edx

        pop     rbp

        ret

.LC0:

        .string "Enter a value for x: "

.LC1:

        .string "Enter a value for c: "

.LC2:

        .string "f(x) = "

.LC3:

        .string "PAUSE"

main:

        push    rbp

        mov     rbp, rsp

        mov     esi, OFFSET FLAT:.LC0

        mov     edi, OFFSET FLAT:_ZSt4cout

        call    std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)

        mov     esi, OFFSET FLAT:x

        mov     edi, OFFSET FLAT:_ZSt3cin

        call    std::basic_istream<char, std::char_traits<char> >::operator>>(unsigned int&)

        mov     esi, OFFSET FLAT:.LC1

        mov     edi, OFFSET FLAT:_ZSt4cout

        call    std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)

        mov     esi, OFFSET FLAT:c

        mov     edi, OFFSET FLAT:_ZSt3cin

        call    std::basic_istream<char, std::char_traits<char> >::operator>>(unsigned int&)

        mov     edx, DWORD PTR c[rip]

        mov     eax, DWORD PTR x[rip]

        mov     esi, edx

        mov     edi, eax

        call    Equation(unsigned int, unsigned int)

        mov     DWORD PTR result[rip], eax

        mov     esi, OFFSET FLAT:.LC2

        mov     edi, OFFSET FLAT:_ZSt4cout

        call    std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)

        mov     rdx, rax

        mov     eax, DWORD PTR result[rip]

        mov     esi, eax

        mov     rdi, rdx

        call    std::basic_ostream<char, std::char_traits<char> >::operator<<(unsigned int)

        mov     esi, OFFSET FLAT:_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_

        mov     rdi, rax

        call    std::basic_ostream<char, std::char_traits<char> >::operator<<(std::basic_ostream<char, std::char_traits<char> >& (*)(std::basic_ostream<char, std::char_traits<char> >&))

        mov     edi, OFFSET FLAT:.LC3

        call    system

        mov     eax, 0

        pop     rbp

        ret

__static_initialization_and_destruction_0(int, int):

        push    rbp

        mov     rbp, rsp

        sub     rsp, 16

        mov     DWORD PTR [rbp-4], edi

        mov     DWORD PTR [rbp-8], esi

        cmp     DWORD PTR [rbp-4], 1

        jne     .L7

        cmp     DWORD PTR [rbp-8], 65535

        jne     .L7

        mov     edi, OFFSET FLAT:_ZStL8__ioinit

        call    std::ios_base::Init::Init() [complete object constructor]

        mov     edx, OFFSET FLAT:__dso_handle

        mov     esi, OFFSET FLAT:_ZStL8__ioinit

        mov     edi, OFFSET FLAT:_ZNSt8ios_base4InitD1Ev

        call    __cxa_atexit

.L7:

        nop

        leave

        ret

_GLOBAL__sub_I_x:

        push    rbp

        mov     rbp, rsp

        mov     esi, 65535

        mov     edi, 1

        call    __static_initialization_and_destruction_0(int, int)

        pop     rbp

        ret