[atom0s]

Using modern compiler optimizations it suggests that doing something like this:

    int32_t val1 = 1234;
    int32_t val2 = -val1;

Translates to:

mov     [ebp+var_4], 4D2h
mov     eax, [ebp+var_4]
neg     eax
mov     [ebp+var_4], eax

which is what mcp suggested in his first suggestion. If you write the code out as:

int32_t val1 = 1234;
val1 *= -1;

It also optimizes to the first suggestion.