HP-41 MCODE printer entries?
09-10-2016, 05:01 AM
Post: #1
 hth Senior Member Posts: 405 Joined: Mar 2014
HP-41 MCODE printer entries?
Has anyone documented stable MCODE entry points that work with all HP-41 printers?

I am aware of the original 82143A printer, the HPIL and the IR module. Are there any other printer ROMs in existence?

Håkan
09-10-2016, 09:56 AM (This post was last modified: 09-10-2016 09:59 AM by J-F Garnier.)
Post: #2
 J-F Garnier Senior Member Posts: 551 Joined: Dec 2013
RE: HP-41 MCODE printer entries?
I'm not sure that there is a printer entry point documentation, but I investigated several years ago, and here are my findings.
There is a table at the end of each printer ROM, that act as defined entry points for several internal printer routines.
There are also a few fixed entry points, because some ROMs (I identified the Time ROM doing it) directly call these entries, and it must work for all printer ROMs.

My list:
Code:
 * FIXED ENTRIES: =OUTPCT   EQU 63DDH =PRTMSG   EQU 6400H =PRTLCD   EQU 6BB9H =IAUALL   EQU 6DB3H * ENTRY TABLE: =PRT18    EQU 6FCBH  goto PRX =PRT17    EQU 6FCDH  goto PRSTK =PRT16    EQU 6FCFH  goto REGL =PRT15    EQU 6FD1H  goto XPRT15 =PRT14    EQU 6FD3H  goto ENDALP =PRT13    EQU 6FD5H  goto OVERFL =PRT12    EQU 6FD7H  goto PRTCAT =PRT11    EQU 6FD9H  goto PAVIEW =PRT10    EQU 6FDBH  goto PVIEW =PRT9     EQU 6FDDH  goto PADV =PRT8     EQU 6FDFH  goto DATA&R =PRT7     EQU 6FE1H  goto PPROMP =PRT6     EQU 6FE3H  goto PMESSG =PRT5     EQU 6FE5H  goto DATA&F =PRT4     EQU 6FE7H  goto DATAPR =PRT3     EQU 6FE9H  goto ALPHOP =PRT2     EQU 6FEBH  goto NXINST =PRT1     EQU 6FEDH  goto PXTR * =ACRGCX   EQU 6FF0H  goto ACREGC =PBYTCX   EQU 6FF2H  goto PBYTEC

The HP82143, HPIL printer and IR printer are the only printer ROMs.
The internal of the IR printer ROM is still unkown, several people (including myself) tried to investigate it, but without success. The IR ROM remains maybe the biggest mysterious part of the whole HP-41C system.

J-F
09-13-2016, 05:45 PM
Post: #3
 hth Senior Member Posts: 405 Joined: Mar 2014
RE: HP-41 MCODE printer entries?
Great! Thanks!

I will get some disassembler output of the IR and 82143A printer so I can compare them a bit.
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