| 摘要 |
Instruction queue 1511 by a fetch stage specifies test instructions TEST2, e.g. AND test or OR-test, and jump-condition-code JCC. TEST 2 fuses a logical AND or OR operation type acting on a first and second source data operand with prior art test instruction for comparing the results of the logical operation against a mask in a third data operand. An execution stage responsive to a decode stage performs the logical operation between first and second operands (where AND or OR tests whether the bits in either source are zero or one, respectively) and compares the results to the mask to set a condition flag CC. Conditional branching JCC, e.g. branching to a slower generic code sequence, is executed depending on the flag. TEST2 and JCC can be fused for execution as a single micro instruction 1526. Performance for frequently executed type testing instruction idioms generated by just-in-time (JIT) compilers is improved. |
