COMPARE AND REPLACE DAT TABLE ENTRY

A first and a second operand are compared. If they are equal, the contents of register R1+1 are stored at the second-operand location, and the specified CPU or CPUs in the configuration are cleared of all TLB table entries of the designated type formed through the use of the replaced entry in storage, and all lower-level TLB table entries formed through the use of the cleared higher-level TLB table entries. A valid DAT table entry is replaced with a new entry, and the Translation Lookaside Buffer (TLB) is purged of any copies of (at least) the single entry on all CPUs in the configuration. If the first and second operands are unequal, the second operand is loaded at the first-operand location. The comparison result is indicated by the condition code. A method, system and a computer program product are provided.