Ref: Your note of Thu, 29 Jun 2023 08:57:50 -0700 The GNU assembler as used for Linux on IBM Z uses a similar "raw" format for instructions to that shown in Principles of Operation, although with some differences. There is more information about it here, comparing with HLASM:
http://linuxvm.org/Present/SHARE99/S8131db.pdf Jonathan Scott, HLASM IBM Hursley, UK
