Conditional Moves

• CMOV R1, R2, R3

  • Move R2 to R1 if R3 = 0

• Main compiler use: If (cond ) S1 (with result in Rres)

  • Compute result of S1 in Rs1
    Compute condition and store in Rcond
    CMOV Rres, Rs1, Rcond
  • Increases register pressure
  • No need (in this example) for branch prediction

• Very useful if condition can be computed ahead

Previous slide

Next slide

Back to first slide

View graphic version