x86 - How to convert a positive number to negative in assembly

Question

I want to convert a positive number to negative in assembly, I need a code sample

The input is in hex sdword

Thanks

Answer 1

Well, there are two ways to do this, best would be to load the number into a register, then use the NEG instruction as Hans mention, ie: NEG EAX would negate eax. The other way would be XOR EAX,EAX SUB EAX,EDX where edx contains the number you want to negate