Every time we add new instruction definitions to the HLASM opcode tables, we create a few test cases for each new instruction which include the expected hex code as a comment, so that we can verify automatically (using CMS Pipelines) that the expected code has been generated.
Our test cases included the WFKHEXBS extended mnemonic, so that has definitely been assembled correctly. That mnemonic was included in the preview updates to Principles of Operation provided by the architects, but it was the last one in the list and appeared on its own at the top of a new column, and appears to have been lost during the merge into the published version. I have informed the current editor about this omission. Jonathan Scott HLASM, IBM Hursley, UK
