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HP-71 Forth/Assembler ROM fix
12-02-2015, 08:02 AM (This post was last modified: 12-02-2015 08:12 AM by J-F Garnier.)
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HP-71 Forth/Assembler ROM fix
I published on my site a simple fix for the two major bugs of the assembler in the Forth ROM (buggy B=B+B A and D1=AS opcodes). I found this fix several years ago, but it now makes sense to publish it since the FRAM71 module now allows to load (and possibly modify) the hardwired part of the Forth/Assembler ROM.

http://www.jeffcalc.hp41.eu/emu71/bug71.html#forth

A couple of simple POKE may implement the fix, after loading the regular ROM:
POKE "E76A8","4" ! instead of "5"
POKE "E76C4","9" ! instead of "8"
Note that the ROM checksum is unchanged by this fix.

I let the FRAM71 experts devise the exact patch loading procedure :-)

J-F
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Messages In This Thread
HP-71 Forth/Assembler ROM fix - J-F Garnier - 12-02-2015 08:02 AM
RE: HP-71 Forth/Assembler ROM fix - Erwin - 11-24-2018, 09:24 PM
RE: HP-71 Forth/Assembler ROM fix - Erwin - 11-24-2018, 10:17 PM
RE: HP-71 Forth/Assembler ROM fix - Erwin - 11-25-2018, 06:12 PM



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