What exactly is the Adaptive Body Bias ?

Can some explain me what exactly is ABB(Addaptive Body Bias) and two body biasing techniques called forward body biasing and Reverse body biasing?

Re: Body Biasing

You are modifying the body potential relative to source
to obtain some different gate characteristic.

Forward biasing the body lowers VT, at about .5-0.7 V/V
(body effect, see model params for your PDK's actual).
You are in a bind here, because you do not want to be
injecting current into the body (parasitic VBJT base)
and initiating either latchup or shunt LBJT conduction
that is non-gate-controlled. But light forward bias will
increase the speed & drive.

Reverse bias may conversely pull you up out of subthreshold
leakage on a lower-VT process. Here you worry about Vdb
(hot carrier) and straight oxide stress enhancement.

Adaptive would mean that you are closing a loop around it,
with some delta-attribute scheme and reference, to get the
behavior you want.