CHAPTER 24. 64-BIT VALUES IN 32-BIT ENVIRONMENT CHAPTER 24. 64-BIT VALUES IN 32-BIT ENVIRONMENT
_f_mul PROC
push ebp
mov ebp, esp
mov eax, DWORD PTR _b$[ebp+4]
push eax
mov ecx, DWORD PTR _b$[ebp]
push ecx
mov edx, DWORD PTR _a$[ebp+4]
push edx
mov eax, DWORD PTR _a$[ebp]
push eax
call __allmul ; long long multiplication
pop ebp
ret 0
_f_mul ENDP
_a$ = 8 ; size = 8
_b$ = 16 ; size = 8
_f_div PROC
push ebp
mov ebp, esp
mov eax, DWORD PTR _b$[ebp+4]
push eax
mov ecx, DWORD PTR _b$[ebp]
push ecx
mov edx, DWORD PTR _a$[ebp+4]
push edx
mov eax, DWORD PTR _a$[ebp]
push eax
call __aulldiv ; unsigned long long division
pop ebp
ret 0
_f_div ENDP
_a$ = 8 ; size = 8
_b$ = 16 ; size = 8
_f_rem PROC
push ebp
mov ebp, esp
mov eax, DWORD PTR _b$[ebp+4]
push eax
mov ecx, DWORD PTR _b$[ebp]
push ecx
mov edx, DWORD PTR _a$[ebp+4]
push edx
mov eax, DWORD PTR _a$[ebp]
push eax
call __aullrem ; unsigned long long remainder
pop ebp
ret 0
_f_rem ENDP
Multiplication and division are more complex operations, so usually the compiler embeds calls to a library functions doing
that.
These functions are described here:E on page 903.
Listing 24.10: Optimizing GCC 4.8.1 -fno-inline_f_mul:
push ebx
mov edx, DWORD PTR [esp+8]
mov eax, DWORD PTR [esp+16]
mov ebx, DWORD PTR [esp+12]
mov ecx, DWORD PTR [esp+20]
imul ebx, eax
imul ecx, edx
mul edx
add ecx, ebx
add edx, ecx
pop ebx