New version of HLASM Toolkit feature SPM macros

For the reasons previously stated, we are not able to use this impressive set of macros and documentation directly, as the differences from the existing ones are too extensive. We added our own support for Compare and Branch instructions and for Carry and Borrow conditions to the existing macros in APAR PH31153 in November 2020. We hope to add further enhancements in future, but this needs to be done in a very cautious and compatible way. We may well be able to make use of ideas from this collection in future, so we are setting it aside for reference. However, we are not able to make use of this alternative implementation directly, so we are declining this requirement.

This is a very interesting and potentially useful collection of enhancements, and addresses many historical requirements against the structured programming macros, using highly ingenious solutions which appear to be generally of high quality. It's an impressive amount of work.

I wish we could use this set "as is". However, the enhancements are so complex and the macros are so different to the current set that it would require a huge amount of resources to review and evaluate this collection, including extensive compatibility verification both for the design and the implementation. At present the requirement for all of this new function is not sufficient to justify such effort, given the limited development resources available to the current team. We also encountered a few bugs (for example, a missing sequence symbol and the "LT" instruction being misinterpreted) as soon as we tried some simple tests, which means we feel it needs very thorough review.

We do have some high priority requirements in this area, for example to support compare and branch instructions, but we believe this can be done by small incremental changes which can easily be verified and regression tested. We also have major reservations about introducing non-trivial logic on top of the standard assembler function, especially transforming existing code to exploit new instructions, as that can become disproportionately complex, like attempting to implement a compiler in the assembler macro language. Note for example that the new Select instructions in the IBM z15 now provide a better solution than load-on-condition in many cases.

We have saved this collection of macros and documentation for now as an illustration of possible enhancements together with the code that implements such enhancements, and we hope it may be practical to pick out specific new function in an incremental way so that we can introduce it in future without risking disruption.

Due to processing by IBM, this request was reassigned to have the following updated attributes:
Brand - Servers and Systems Software
Product family - Enterprise Tooling
Product - High Level Assembler (HLASM)

For recording keeping, the previous attributes were:
Brand - WebSphere
Product family - Enterprise Tooling
Product - High Level Assembler (HLASM)

Due to processing by IBM, this request was reassigned to have the following updated attributes:
Brand - WebSphere
Product family - Enterprise Tooling
Product - High Level Assembler (HLASM)
Component - Toolkit
Operating system - IBM z/OS

For recording keeping, the previous attributes were:
Brand - Servers and Systems Software
Product family - zSeries Software
Product - z/OS
Component - Other
Operating system - IBM z/OS

Creating a new RFE based on Community RFE #67135 in product z/OS.

Attachment (Description): suggested replacement for ch 2 of "HLASM Toolkit Feature User's Guide"

Attachment (Description): Macro source. Test example source.