HP-41 Boost module 0B and OS4 version 2A

[hth]

Updated Boost module released, together with an updated OS4.

Highlights:

• Now with a manual
• Direct access to X-memory data files using XSTO, XRCL etc
• Dual operand compares, <, <=, =, not-equal, combine your own compares, IND Z <= 05 ?
• Dual register exchange, IND 05 <> 02, also between normal registers and X-memory file: Z <>X 05 (exchange Z with register 05 in current data file).
• Dynamic stack buffer, push alpha, registers, RPN stack, flag, return stack, data registers. Makes it easy to write RPN code that preserves registers that you do not want to disturb.
• The dynamic stack makes it easy to write RPN functions that take a parameter from X (or X and Y), internally mess up registers and finally return something in X, preserving the rest of the stack and having old X value moved to L. Simply push the stack with PUSHST, restore with POPFLXL (pop stack, keep new X and move old X to L), POPDRXL is similar, but simulates taking parameters from X and Y, dropping the stack when registers are restored in a similar fashion.
• Many more functions provided.
  

Versions for ordinary HP-41 models as well as HP-41CL (with speed annotations) available.

Available now from:
https://github.com/hth313/boost41/releases/tag/v0B
https://github.com/hth313/OS4/releases/tag/v2A