19.3 Flags stalls after shifts and rotates
You can get a stall resembling the partial flags stall when reading any flag bit after a shift or rotate, except for shifts and rotates by one (short form):
SHR EAX,1 / JZ XX ; no stall SHR EAX,2 / JZ XX ; stall SHR EAX,2 / OR EAX,EAX / JZ XX ; no stall SHR EAX,5 / JC XX ; stall SHR EAX,4 / SHR EAX,1 / JC XX ; no stall SHR EAX,CL / JZ XX ; stall, even if CL = 1 SHRD EAX,EBX,1 / JZ XX ; stall ROL EBX,8 / JC XX ; stall
The penalty for these stalls is approximately 4 clocks.