FTB_SHI#
Format: FTB_SHI dest, source.
Phase0: FTB_SHI FT3, (S2)
Phase1: -
Phase2: -
Description: Find top bit with signal
Find the first 0 from the MSB if the number is negative, else the first 1 from the MSB. Return -1 if no bits set.
Example:
c=0;
while ((S2[31] ^ S2)>>c) ++c;
FT3=c-1;