Flow of control – Conditional branches

• About 30% of executed instructions

  • Generally PC-relative

• Compare and branch

  • Only one instr. but a “heavy one”; Often limited to equality/inequality or comparisons with 0

• Condition register

  • Simple but uses a register and uses two instructions

• Condition codes

  • CC is extra state (bad for pipelining) but can be set “for free” and allow for branch executing in 0 time

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