Open to work | ✯ https://xitter.cf/t.co/GIde268mPb | prev. @onchainheroes
mload(0x40)
Joined January 2015
- Tweets374
- Following1.2K
- Followers911
- Likes8K
Pinned Tweet
New article: deriving the math behind Solady's 67-byte, 114-gas sqrt(x) from first principles.
The Solady CLZ PR just merged! 🚀
github.com/Vectorized/solady…
No magic multipliers
Exactly 6 Babylonian iterations
1 floor correction
Full derivation 👇
atarpara retweeted
Best book to understand ZK math for Groth16
hackmd.io/@Sahil4555/zk/%2Fp…
1/4 Answer: Version D1 is cheaper by 6 gas! 🎉
This behavior is caused by the Solidity compiler's internal "stack scheduling" heuristic during code generation.
It seems counterintuitive to delay a revert check, but on the happy path, it makes a massive difference to stack layout. Here is exactly why:
3/4
JUMPI pops condition + destination — whatever's left is exactly what the fall-through block opens with.
Compare both snapshots right after JUMPI:
D1 → [lo, rem, d, extra] all 4 live — SUB/DIV/ADD fire directly
D2 → [b, a, d, lo] rem and extra don't exist yet
In D2, MULMOD needs [a, b, d] on top.
Block B opens with [b, a, d, lo].
Two ops fix it:
DUP3 [d, b, a, d, lo] <--- copy d
SWAP2 [a, b, d, d, lo] <--- reorder args for MULMOD
4/4 DUP3 + SWAP2 = 6 gas. Two opcodes. That's the entire delta.
Solady already uses this in FixedPointMathLib.sol (fullMulDiv):
r := mulmod(x, y, d) ← before check
t := and(d, sub(0, d)) ← before check
if iszero(...) { revert }
Rule: batch intermediates before the revert check.
One unified block → compiler plans the full layout.
JUMPI in the middle → fall-through starts blind.
Solady update:
Added a CLZ variant to LibRLP.
LibRLP.encodeUint() is now 118 gas cheaper.
PR: github.com/Vectorized/solady…
More optimizations coming soon.
New article: deriving the math behind Solady’s `cbrt(x)` implementation from first principles.
What is the 0x90b5e5 constant actually doing?
original implementation by @duncancmt
* Why cube root needs magic multipliers
* Why sqrt does not
* Optimal Initial guess
* Exactly 5 Newton Rashson iterations
Full blog post: atarpara.github.io/solady-cb…
The quirk: Integer Babylonian iterations get stuck bouncing between floor and ceil forever if x+1 is a perfect square (like x=15).
`sub(z, lt(div(x, z), z))` is the floor correction. It catches the cycle and subtracts 1.
10 mathematical facts packed into 8 lines of Yul.
Deep math beats brute force in EVM optimization.
Thanks to @duncancmt for formally verifying this in 0x-settler.
Full blog post link : atarpara.github.io/solady-sq…
atarpara retweeted
Ethereum’s next major upgrade, “Fusaka”, goes live in less than 48 hours.
I read all 13 EIPs being included so you don’t have to.
So, here are 13 tweets (with diagrams) to explain the 13 upgrades in simple terms: 🧵
Hey @solidity_lang, the community is eagerly waiting for the Solidity Summit 2025 recordings! 🗓️ The speaker lineup looked amazing. Any ETA on when they’ll hit YouTube or anywhere else?
Thanks!
If solady has a million fans then I am one of them
If solady has ten fans then I am one of them
If solady has only one fan then that is me
If solady has no fans then that means I am no longer on earth
If the world is against solady then I am against the world
