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c3d
db48x
C++2024–2026
c3d / db48x

db48x

RPL runtime for the DM42 calculator, in the spirit of HP48/49/50

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4Distinct people
9Mentions
0Explicit recommenders
297GitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

RPL runtime for the DM42 calculator, in the spirit of HP48/49/50

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:03:16 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by month9 dated mentions

Observed mentions: 2024-11-06 22:26:22 UTC to 2026-03-05 07:18:51 UTC.

0123452024-11-01 00:00:00 UTC to 2024-12-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 commentsNov 20242024-12-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-01-01 00:00:00 UTC to 2025-02-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-02-01 00:00:00 UTC to 2025-03-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-03-01 00:00:00 UTC to 2025-04-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-04-01 00:00:00 UTC to 2025-05-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-05-01 00:00:00 UTC to 2025-06-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-06-01 00:00:00 UTC to 2025-07-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-07-01 00:00:00 UTC to 2025-08-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 commentsJul 20252025-08-01 00:00:00 UTC to 2025-09-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-09-01 00:00:00 UTC to 2025-10-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-10-01 00:00:00 UTC to 2025-11-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-11-01 00:00:00 UTC to 2025-12-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2025-12-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2026-01-01 00:00:00 UTC to 2026-02-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2026-02-01 00:00:00 UTC to 2026-03-01 00:00:00 UTC (exclusive): 1 mentions; 1 submissions, 0 comments2026-03-01 00:00:00 UTC to 2026-04-01 00:00:00 UTC (exclusive): 5 mentions; 0 submissions, 5 commentsMar 2026

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
Nov 20242024-11-01 00:00:00 UTC2024-12-01 00:00:00 UTC202
Dec 20242024-12-01 00:00:00 UTC2025-01-01 00:00:00 UTC000
Jan 20252025-01-01 00:00:00 UTC2025-02-01 00:00:00 UTC000
Feb 20252025-02-01 00:00:00 UTC2025-03-01 00:00:00 UTC000
Mar 20252025-03-01 00:00:00 UTC2025-04-01 00:00:00 UTC000
Apr 20252025-04-01 00:00:00 UTC2025-05-01 00:00:00 UTC000
May 20252025-05-01 00:00:00 UTC2025-06-01 00:00:00 UTC000
Jun 20252025-06-01 00:00:00 UTC2025-07-01 00:00:00 UTC000
Jul 20252025-07-01 00:00:00 UTC2025-08-01 00:00:00 UTC000
Aug 20252025-08-01 00:00:00 UTC2025-09-01 00:00:00 UTC000
Sep 20252025-09-01 00:00:00 UTC2025-10-01 00:00:00 UTC000
Oct 20252025-10-01 00:00:00 UTC2025-11-01 00:00:00 UTC000
Nov 20252025-11-01 00:00:00 UTC2025-12-01 00:00:00 UTC101
Dec 20252025-12-01 00:00:00 UTC2026-01-01 00:00:00 UTC000
Jan 20262026-01-01 00:00:00 UTC2026-02-01 00:00:00 UTC000
Feb 20262026-02-01 00:00:00 UTC2026-03-01 00:00:00 UTC110
Mar 20262026-03-01 00:00:00 UTC2026-04-01 00:00:00 UTC505

What Hacker News says

9 sources
c3d·Mar 5, 2026
DB48x certainly has a GitHub site with freely downloadable pieces of software that can run on the calculator. For instance here: https://github.com/c3d/db48x/tree/stable/library Some of these include contributions from third parties. The problem is that the law is written without a precise enough wording that would ensure that there is no risk whatsoever for me. And the penalty is stiff, something like $7500 per child using the software. As for mandating age verification, it's unclear to me how you think that it's possible to deliver an API giving age bracket info (in the case of DB48x, the idiomatic way would be an RPL command that returns that info) without having a facility to enter age or date of birth or something like that. So yes, everyone who reads the text interprets it as mandating age verification.
In Open source calculator firmware DB48X forbids CA/CO use due to age verification
c3d·Nov 6, 2024
> Where's the apostrophe (equiv. to quote in lisp)? That should be an easily accessible key not buried in a menu. The apostrophe is on the XEQ key of the DM42, or "F". But in RPL, it is not to quote like in Lisp, but to introduce algebraic expressions (although it does quote names as a side effect). On the simulator / web site, the symbol on the key looks like this: [' ()], it is on the second row on the rightmost column, see https://github.com/c3d/db48x/blob/stable/DB48X-Keys/DB48X-Ke.... The key is labeled like this because it serves a dual purpose to accommodate the smaller number of keys on the DM42 relative to the HP48. It adds a tick when not inside an expression, which in RPL begins an algebraic expression. When you are inside an algebraic expression, then you don't need tick anymore, so the key inserts parentheses inside. > - Why
Read the rest
did he swap the log keys? Because I personally prefer to have exp and ln rather than ln and log. I also would prefer to have y^x as a primary, unshifted key, and this change is coming soon. But I recognize that keyboard layout is a personal preference, so I'm currently working on making this customizable. Recently, "User mode" has been introduced, which lets you reconfigure the keyboard the way you want. So if you want to restore decimal LOG as the primary key instead of EXP, then do this: 'LOG10' 24.1 ASN. You should be able to restore EXP to the original position with 'EXP' 25.2 ASN, but there is bug with shifted user keys that I need to fix. This should be fixed in the next release. In addition, the very next release should offer three layouts: 1) One that is maximally compatible with DM42 / HP42, which I assume is what you want. 2) One that corresponds to the current layout, so that people with existing overlays can keep them. 3) One that corresponds to a new iteration of the key layout that is better suited for DB48x, which is currently being discussed on the HP Museum forum.
In DB48X: High Performance Scientific Calculator, Reinvented

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