Submission timeline
2007–2026One slot for every year since HN launched. Height is that year's peak points; orange marks a 100+ point or 50+ comment breakout. Select a bar to open its strongest thread.
First comments on top threads
HN comment orderIn hardware this would be called a carry save adder [1]. One interesting fact about carry save adders is that the carry part of the register can be extended in order to avoid any carrying between words for very long periods of time. Instead of using 53 bits to represent 52 bits, use 60 bits, and now you can perform 256 sequential additions with no carrying between words before the carry part saturates and needs to be handled. Somewhat surprisingly…
> Aside: Why 13 bits instead of 12? For our purposes, we’re going to ignore the carries in the most significant limb, allowing numbers to wrap when they overflow past 2256 - 1 (just like how unsigned addition works in C with normal size integer types). As a result, we can assign 52 bits to the most significant limb and ignore the fact that it will run out of room for carries before the other limbs do. Why not give…
I believe the general name of this trick is "carry save addition". https://en.wikipedia.org/wiki/Carry-save_adder
The first top-level comment from each of the four biggest threads, in HN’s own order. Excerpts are shortened; open a comment for full context.
- Breakout years
- 2
- Total points
- 1004
- Total comments
- 171
100+ points or 50+ comments
reference only — not used in Hall rules or ranking
reference only — not used in Hall rules or ranking
Every submission
| Date | Title as submitted | By | Points | Comments |
|---|---|---|---|---|
| 2020-05-29 | The radix 2^51 trick (2017)First breakout · Best thread | mooreds | 518 | 83 |
| 2022-05-30 | The radix 2^51 trick (2017) | ddtaylor | 2 | 0 |
| 2022-11-22 | The radix 2^51 trick | shkhuz | 51 | 6 |
| 2022-11-22 | The radix 2^51 trick | ot | 2 | 0 |
| 2025-05-30 | The radix 2^51 trick (2017)Hall induction · Latest 20+ point return | blobcode | 431 | 82 |