We have just shipped APAR PH50915, an enhancement to code page support, which makes it possible to identify the source code page and specify the object code pages to be used for EBCDIC, ASCII and Unicode constants (now including UTF-8):
https://www.ibm.com/support/pages/apar/PH50915 Additional information is provided in a separate support document linked from the APAR page. For compatibility, the existing CODEPAGE option using a loaded conversion table is still supported, but there is a new warning ASMA230W issued for the first CU constant if the specified code page number is inconsistent with the EBCDIC source code page. This is an unfortunate exception to the normal rule that existing programs are not affected by HLASM maintenance, not only generating the same binary code but also not giving any new warning messages. We felt that we should call attention to inconsistent conversion options, but since the default options are inconsistent for compatibility reasons this means we have to warn for existing programs (unless the user has changed the CODEPAGE to 1140, the Euro equivalent of 37, which is accepted as sufficiently consistent). The message can be suppressed with SUPRWARN if necessary, but the recommended approach is to use CODEPAGE(LOCAL) which then uses an internally generated table for Unicode based on the EBCDIC source code page. Jonathan Scott, HLASM IBM Hursley, UK
