NEW: HP 15C Collectors Edition

[J-F Garnier]

(11-03-2023 04:08 PM)Divasson Wrote:  

(11-03-2023 02:47 PM)ebs Wrote:  According to The Calculator Store blog, the patch is just a change of a couple of bytes in the HP16C rom (but doesn't say which bytes), so it's possible to do it with a hex editor. No need to redistribute the entire firmware that would require HP/Moravia approval.

Actually 3 bytes. I'd leave the author to comment/explain - his baby, not mine.

I believe there is no more any reason to keep it confidential.

The 16c ROM patches are:
06ef:000 (was:346)
06f0:000 (was:1cb)
0718:3ac (was:17a)
(addresses are the 10-bit word addresses expressed in the 16c ROM space)

Actually, it's more a workaround than a fix, because it doesn't correct the emulator weakness but just works around it taking advantage of the 16C hex>dec code structure and using the existing emulator's possibilities (basically replacing the offending opcode with a replacement opcode that is known to work for this particular case).
Also, since only the 16c ROM is patched and not the emulation engine itself, the 15c modes are not affected in any way.

J-F