x86 Assembly: INC and DEC instruction and overflow flag

Question

In x86 assembly, the overflow flag is set when an add or sub operation on a signed integer overflows, and the carry flag is set when an operation o

Answer 1

What the processor does is set the appropriate flags for the results of these instructions (add, adc, dec, inc, sbb, sub) for both the signed and unsigned cases i e two different flag results for every op. The alternative would be having two sets of instructions where one sets signed-related flags and the other the unsigned-related. If the issuing compiler is using unsigned variables in the operation it will test carry and zero (jc, jnc, jb, jbe etc), if signed it tests overflow, sign and zero (jo, jno, jg, jng, jl, jle etc).