Synthetic programming (HP-41): Difference between revisions

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'''Synthetic programming''' is an advanced technique for [[Mathematical programming|programming]] the [[HP-41C]] and [[Elektronika B3-34]] [[Programmable calculator|calculators]], involving creating [[Instruction (computer science)|instructions]] (or combinations of instructions and operands) that cannot be obtained using the standard capabilities of the calculator.<ref name=IEEE/>

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'''Synthetic programming''' is an advanced technique for [[Mathematical programming|programming]] the [[HP-41C]] and [[Elektronika B3-34]] [[Programmable calculator|calculators]], involving creating [[Instruction (computer science)|instructions]] (or combinations of instructions and operands) that cannot be obtained using the standard capabilities of the calculator.<ref name="IEEE"/>

Some HP-41C instructions are coded in memory using multiple [[byte]]s. Some of these sequence of bytes correspond to instructions the calculator is able to execute, but these cannot be entered in the program memory using conventional program entry methods (''i.e.'' using the calculator as described in the user's manual.) Synthetic programming uses a [[Softwaresoftware bug|bug]] in the calculator firmware to enter those byte sequences as a sequence of other instructions, then partially skipping halfway through the first instruction, so that the calculator believes the end of the first instruction is actually the beginning of a new one.

It is not clear if the creators behind the HP-41 were aware of all these "black holes". HP did not officially support these techniques, but probably was intrigued by the strange operations and in some cases allowed enthusiasts to practice in their offices and helped to improve it among a whole sense of curiosity.

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==Further reading==

* {{cite book |isbn=0-96252580-4 |title=Synthetic Programming on the HP-41C |author-last=Wickes |author-first=William C. |date=1980 |isbn=0-96252580-4}}

* {{cite book |author-last=Jarett |author-first=Keith |date=1982 |title=HP-41 Synthetic Programming Made Easy |___location=United States |publisher=Synthetix}}

* {{cite book |isbn=0-9612174-4-8 |title=Inside the HP-41C |author-last=Dodin |author-first=Jean-Daniel |date=1985 |isbn=0-9612174-4-8}}

* {{cite book |isbn=0-9510733-0-3 |title=Extend Your HP-41 |author-last=Mier-Jedrzejowicz |author-first=Wlodek |date=1985 |isbn=0-9510733-0-3}}

* {{cite book |isbn=0-9612174-6-4 |title=HP-41 Advanced Programming Tips |author-last1=McCornack |author-first1=Alan |author-last2=Jarett |author-first2=Keith |date=1987 |isbn=0-9612174-6-4}}

* [http://nonpareil.brouhaha.com/microcode_simulation.pdf{{cite web |title=Microcode-Level Calculator Simulation], by |author-first=Eric |author-last=Smith, presented at 2004 |___location=Hewlett-Packard Handheld Conference in San Jose, California, onUSA |date=2004-09-26 September 2004|url=http://nonpareil.brouhaha.com/microcode_simulation.pdf}}

== See also==

* [[Yeggogology]] (Cyrillic: "Еггогология")

[[Category:HP programmable calculators| Synthetic programming]]