Compare and Branch
A compare is a subtract that does not store its results; however, the results set the condition code, which can be tested by branch instructions.
| cmp | A,B | compare A - B , integer | ||
| fcmpd | A,B | compare A - B , floating | ||
The branch instructions test the condition code:
| ba | Branch always. | ||
| ble | fble | Branch if A &le B | |
| be | fbe | Branch if A = B | |
| bne | fbne | Branch if A &ne B | |
| bge | fbge | Branch if A &ge B | |
| bl | fbl | Branch if A < B | |
| bg | fbg | Branch if A > B | |
| nop | no operation | ||
Note that the effect of a branch is delayed by one instruction; therefore, a branch or call must be followed by an instruction, which may be useful or a nop. The instruction following the branch is executed before the branch is taken.