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static recompilation of the HP-15C ROM
02-16-2014, 11:33 AM
Post: #4
RE: static recompilation of the HP-15C ROM
given that the 15C rom contains, what, a few thousand instructions, the result of static recompilation would probably easily fit within the available flash of many modern controllers. the pic32mx150, for instance, has 128k of flash available. i reckon this would be enough. if the flash is there, there is no good reason not to use it if it makes the job easier.

and the advantages are several:

- code that can be added to without need for trapping or worrying about the IP address, in order to fix bugs or add enhancements. it is possible to add in C code between the execution of the original instructions, and even modify individual instances of an instruction if needsbe. over time, some blocks of instructions may benefit from being hand-translated into 'pure C'. as i said before, moving to displaying instruction mnemonics instead of key codes becomes quite achievable.

- a source base that arguably side-steps copyright issues, in that it does not contain a copy of the original rom in any form that can be directly recognized or extracted. this is how microsoft basic gets away with being freely distributed. the code ends up representing just the algorithms.

- the whole development process can be divided up into a number of stages and blocks that can be achieved across many members of a group. quite literally, once the data structures are decided upon, each saturn instruction can be coded in C by a different person. it then becomes a true community effort with no need for a single author.

tasks might be:
- design data structures,
- create one or more I/O libraries (one for each desired platform),
- a team to work on instruction decoding for the static recompiler
- a number of individuals to re-encode instructions as blocks of 'C' code

rob :-)
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RE: static recompilation of the HP-15C ROM - robert rozee - 02-16-2014 11:33 AM

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