Change sign of fixed point number

[akarpilow]

I know that the first bit in a signed fixed-point number is the sign (0=+, 1=-) but is there an efficient way to invert this sign? It seems like it would be straight forward to just change a 0 to a 1 or a 1 to a 0 but I didn't find any FPGA functions doing this. It feels like overkill to multiply the number by -1. Do I have to somehow convert from fixed point to binary and change the leading bit directly?

Thank you for your help!

[GerdW · Accepted solution]

Hi pilow,

have you tried to negate the FXP number?

[akarpilow]

Oh damn! That works for fixed point too?  When I saw it I thought it was only for floating point. Well I'm embarrassed now. 😅 Thanks for your help.