Method and apparatus for using condition codes to nullify instru

Details Method and apparatus for using condition codes to nullify instru Method and apparatus for using condition codes to nullify instru

1995-06-07

1998-09-29

Lall, Parshotam S.

395581, G06F 930

Patent

active

058156950

ABSTRACT:
The invention is a method and apparatus for conditionally nullifying a current instruction based on a first test value where the first test value can be set in one or more prior instructions and where the execution of the current instruction can set a second test value without affecting the first test value. The one or more prior instructions which set the first test value need not immediately precede the current instruction. In a preferred embodiment, a test value comprises multiple bits, each bit capable of representing a unique state. A mask is provided to select the bits which are being tested. Also, means are provided for specifying an logical operation to be performed on the test values. The invention permits multiple status test results to be saved and concurrently tested in a single branch instruction.

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