The addition of relative addressing and immediate operands has provided the
opportunity to greatly simplify a lot of code.



However, I have found two cases where new instructions are still needed.



In the first case, I need to branch into a branch table using an index -



B             BTABLE(R2)



BTABLE B             RTN01

B             RTN02

B             RTN03

B             RTN04



There is no relative branch instruction which provides indexing.



In the second case, I need to be able to execute a instruction from a table
using an index -



EX           0,ITABLE(R3)



ITABLE  OI           FLG1,X'80'

OI           FLG1,X'40'

OI           FLG2,X'08'

OI           FLG3,X'01'



I would like to see two new instructions -



Branch Relative Unconditional with Indexing



Execute Relative with Indexing



As far as mnemonics for these instructions, I will suggest the following -



BRUX     Branch Relative Unconditional with Indexing



EXRX      Execute Relative with Indexing



Now, how important are these instructions?



For the proposed BRUX instruction, I would say that it is essential.



For the proposed EXRX instruction, I would say that it is highly desirable,
but not essential.



I welcome any comments you may have.



John P. Baker

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