Simple Assembly Output

C code (full program)

int main(void)
{
  int a = 1;
  int b = 2;
  int c = 3;
  int d = 4;
  int e = a * b * (c + d);
  return 0;
}

Compiler-generated assembly code (32-bit)

GNU (simple.s) gcc -S simple.c

Microsoft 7.1 (simple.asm) cl -c -FA simple.c

.file "simple.c" .def ___main; .scl 2; .type 32; .endef .text .globl _main .def _main; .scl 2; .type 32; .endef _main: pushl %ebp movl %esp, %ebp subl $24, %esp andl $-16, %esp movl $0, %eax addl $15, %eax addl $15, %eax shrl $4, %eax sall $4, %eax movl %eax, -24(%ebp) movl -24(%ebp), %eax call __alloca call ___main movl $1, -4(%ebp) movl $2, -8(%ebp) movl $3, -12(%ebp) movl $4, -16(%ebp) movl -4(%ebp), %eax movl %eax, %edx imull -8(%ebp), %edx movl -16(%ebp), %eax addl -12(%ebp), %eax imull %edx, %eax movl %eax, -20(%ebp) movl $0, %eax leave ret

TITLE simple.c .386P include listing.inc if @Version gt 510 .model FLAT else _TEXT SEGMENT PARA USE32 PUBLIC 'CODE' _TEXT ENDS _DATA SEGMENT DWORD USE32 PUBLIC 'DATA' _DATA ENDS CONST SEGMENT DWORD USE32 PUBLIC 'CONST' CONST ENDS _BSS SEGMENT DWORD USE32 PUBLIC 'BSS' _BSS ENDS _TLS SEGMENT DWORD USE32 PUBLIC 'TLS' _TLS ENDS FLAT GROUP _DATA, CONST, _BSS ASSUME CS: FLAT, DS: FLAT, SS: FLAT endif PUBLIC _main _TEXT SEGMENT _a$ = -4 _b$ = -8 _c$ = -12 _d$ = -16 _e$ = -20 _main PROC NEAR push ebp mov ebp, esp sub esp, 20 ; 00000014H mov DWORD PTR _a$[ebp], 1 mov DWORD PTR _b$[ebp], 2 mov DWORD PTR _c$[ebp], 3 mov DWORD PTR _d$[ebp], 4 mov eax, DWORD PTR _a$[ebp] imul eax, DWORD PTR _b$[ebp] mov ecx, DWORD PTR _c$[ebp] add ecx, DWORD PTR _d$[ebp] imul eax, ecx mov DWORD PTR _e$[ebp], eax xor eax, eax mov esp, ebp pop ebp ret 0 _main ENDP _TEXT ENDS END

Compiler-generated assembly code (64-bit)

GNU (simple.s) gcc -S simple.c
.file "simple.c" .text .globl main .type main, @function main: .LFB0: pushq %rbp movq %rsp, %rbp movl $1, -20(%rbp) movl $2, -16(%rbp) movl $3, -12(%rbp) movl $4, -8(%rbp) movl -20(%rbp), %eax imull -16(%rbp), %eax movl -12(%rbp), %ecx movl -8(%rbp), %edx addl %ecx, %edx imull %edx, %eax movl %eax, -4(%rbp) movl $0, %eax popq %rbp ret