generating assembly from c/c++ native code

  1. speed
  2. size
  3. low-level access (registers)

HLL to Assembly Code
HLL compilers translate mathematical expressions into assembly language. You can do it also. For example in C++: int Rval; int Xval = 26; int Yval = 30; int Zval = 40; ... Rval = (Yval - Zval) - Xval; // (30-40) - 26 = -36
...and in assembly: mov eax, Xval neg eax ; EAX = -26 mov ebx, Yval sub ebx, Zval ; EBX = -10 add eax, ebx mov Rval, eax ; -36 ... Rval DWORD ? Xval DWORD 26 Yval DWORD 30 Zval DWORD 40
... and mixing it up: int Rval; int Xval = 26; int Yval = 30; int Zval = 40; __asm { mov eax, Xval neg eax ; EAX = -26 mov ebx, Yval sub ebx, Zval ; EBX = -10 add eax, ebx mov Rval, eax ; -36 } ** note that you can NOT define assembly data in mixed code - why??? note that you can NOT use the OFFSET operator in mixed code -- why??

Disassembly Code
DISASSEMBLY: C++ to Assembly - example... =========================== random code from a sudoku program... case 1: //////////////////////////////////////////////////// // generate & print simple grid WITH repetitions // /////////////////////////////////////////////////// timeStart = time(0); 0044E4FA push 0 0044E4FC call time (44EE00h) 0044E501 add esp,4 0044E504 mov dword ptr [ebp-68h],eax // allocate dynamic memory on the heap grid1=new int[SZp*SZp]; 0044E507 mov eax,dword ptr [ebp-80h] 0044E50A imul eax,dword ptr [ebp-80h] 0044E50E xor ecx,ecx 0044E510 mov edx,4 0044E515 mul eax,edx 0044E517 seto cl 0044E51A neg ecx 0044E51C or ecx,eax 0044E51E push ecx 0044E51F call operator new[] (440ADCh) 0044E524 add esp,4 0044E527 mov dword ptr [ebp-248h],eax 0044E52D mov eax,dword ptr [ebp-248h] 0044E533 mov dword ptr [ebp-14h],eax // init grids to all zeroes initGridP(grid1, SZp); 0044E536 mov eax,dword ptr [ebp-80h] 0044E539 push eax 0044E53A mov ecx,dword ptr [ebp-14h] 0044E53D push ecx 0044E53E call initGridP (440820h) 0044E543 add esp,8 // generate grid using random numbers(1 to gridsize) simpleGridP(grid1, SZp); 0044E546 mov eax,dword ptr [ebp-80h] 0044E549 push eax 0044E54A mov ecx,dword ptr [ebp-14h] 0044E54D push ecx 0044E54E call simpleGridP (4406DBh) 0044E553 add esp,8 printGridP(grid1, SZp); 0044E556 mov eax,dword ptr [ebp-80h] 0044E559 push eax 0044E55A mov ecx,dword ptr [ebp-14h] 0044E55D push ecx 0044E55E call printGridP (441ED7h) 0044E563 add esp,8 cout << "Simple random grid with NO CHECK for repetitions..." << endl; 0044E566 push offset std::endl (44077Bh) 0044E56B push offset string "Simple random grid with NO CHECK"... (4C5EC0h) 0044E570 push offset std::cout (4DEFE0h) 0044E575 call std::operator<< > (441248h) 0044E57A add esp,8 0044E57D mov ecx,eax 0044E57F call std::basic_ostream >::operator<< (441284h) // release allocated memory delete []grid1; 0044E584 mov eax,dword ptr [ebp-14h] 0044E587 mov dword ptr [ebp-23Ch],eax 0044E58D mov ecx,dword ptr [ebp-23Ch] 0044E593 push ecx 0044E594 call operator delete[] (4401EAh) 0044E599 add esp,4 // time stamp cout << "Seconds used is " << time(0)-timeStart << endl; 0044E59C push offset std::endl (44077Bh) 0044E5A1 push 0 0044E5A3 call time (44EE00h) 0044E5A8 add esp,4 0044E5AB mov ecx,eax 0044E5AD mov esi,edx 0044E5AF mov eax,dword ptr [ebp-68h] 0044E5B2 cdq 0044E5B3 sub ecx,eax 0044E5B5 sbb esi,edx 0044E5B7 push esi 0044E5B8 push ecx 0044E5B9 push offset string "Seconds used is " (4C5EACh) 0044E5BE push offset std::cout (4DEFE0h) 0044E5C3 call std::operator<< > (441248h) 0044E5C8 add esp,8 0044E5CB mov ecx,eax 0044E5CD call std::basic_ostream >::operator<< (441D29h) 0044E5D2 mov ecx,eax 0044E5D4 call std::basic_ostream >::operator<< (441284h) break; 0044E5D9 jmp $LN4+62h (44EAECh)