Question

1. Evaluate (3b/2+c)*(6b-a) by writing the code in assembly.

where a=2, b=3 and c=5.

2. Write the equivalent C++ code in assembly language.

if (bx<= ax) && ( cx > dx )

{

ax = 5;

dx = 6;

}

NOTE: Only use 16 bit or 8 bit registers like ax,bx,cx,dx or al,bl,cl,dl. You can either do this using loop statement or conditional or unconditional jmps in assembly language. Keep the code as simple as possible. For question you need to use cmp in assembly language to compare the values. You need to ask from the user the values of ax,bx,cx and dx as input.

Answer 1

       push    rbp
        mov     rbp, rsp
        sub     rsp, 16
        mov     DWORD PTR [rbp-4], 2
        mov     DWORD PTR [rbp-8], 3
        mov     DWORD PTR [rbp-12], 5
        mov     edx, DWORD PTR [rbp-8]
        mov     eax, edx
        add     eax, eax
        add     eax, edx
        mov     edx, eax
        shr     edx, 31
        add     eax, edx
        sar     eax
        mov     edx, eax
        mov     eax, DWORD PTR [rbp-12]
        lea     ecx, [rdx+rax]
        mov     edx, DWORD PTR [rbp-8]
        mov     eax, edx
        add     eax, eax
        add     eax, edx
        add     eax, eax
        sub     eax, DWORD PTR [rbp-4]
        imul    eax, ecx
        mov     DWORD PTR [rbp-16], eax
        mov     eax, DWORD PTR [rbp-16]
        mov     esi, eax
        mov     edi, OFFSET FLAT:_ZSt4cout
        call    std::basic_ostream<char, std::char_traits<char> >::operator<<(int)
        mov     eax, 0
        leave
        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     .L5
        cmp     DWORD PTR [rbp-8], 65535
        jne     .L5
        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
.L5:
        nop
        leave
        ret
_GLOBAL__sub_I_main:
        push    rbp
        mov     rbp, rsp
        mov     esi, 65535
        mov     edi, 1
        call    __static_initialization_and_destruction_0(int, int)
        pop     rbp
        ret