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HP-41 program checksum - Printable Version

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HP-41 program checksum - Jean-Marc - 04-18-2006

Hi, does anyone know how to recall the Checksum
of an HP-41 program in Extended memory? ( perhaps synthetic instructions? )
Best regards,

Re: HP-41 program checksum - Doug Wilder - 04-18-2006

Hi JeanMarc,

The checksum is stored as the first byte after the END. Locating it is somewhat difficult, yet EMDIR gives important data. Remember that there are two registers (overhead) used for filename and pointers.

Recall of the data is another problem. One would suppose that lowering the curtain then using RCL 00 would suffice, unfortunately the RCL function normalizes (distroys) the data. The only HP module that I know of that can do a non-normalized recall is the HP-IL Development module (RG-BUFX function with lowered curtain).

Best regards,

Re: HP-41 program checksum - Jean-Marc - 04-21-2006

Hi Doug,
thank you for these informations.
Best regards.