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[34S] Proposal for Entry RPN mode with dynamic stack
02-20-2015, 09:42 AM
Post: #64
RE: [34S] Proposal for Entry RPN mode with dynamic stack
(02-19-2015 01:51 PM)Bit Wrote:  I'd expect trouble with library and user programs. If they change the RPN mode and get paused or interrupted, it'd be a major source of confusion for the user if the ENTER key suddenly works differently, especially as it may not be noticed right away. If the mode change only affects the program (e.g. it's stored as a local flag), then what should happen if you single step a program? I can't think of a good solution other than rewriting all library routines so they work correctly in both RPN modes and warn users that their programs will break unless they pay attention to this.
Let's assume that the behavioural changes effect ENTER (and perhaps a few other functions), we could introduce a new opcode for it. Thereby, existing code would continue to function as is (interpreted in Classical RPN mode), without any necessary preconditions to be met or modes to be preserved and enforced for specific routines. If the calculator is in Classical RPN mode, it would store the old opcode in program memory, if it is in Entry RPN mode, it would use the new opcode instead. Programming outside the calculator, different mnemotics would have to be used for the two flavours, f.e. ENTER↑ and ENTER or something along that line, or the same mnemotic would translate to different opcodes depending on the mode of the assembler.



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RE: [34S] Proposal for Entry RPN mode with dynamic stack - matthiaspaul - 02-20-2015 09:42 AM

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