-
Notifications
You must be signed in to change notification settings - Fork 1.3k
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
pulley: Implement 16x8 arithmetics #9904
Conversation
Subscribe to Label Actioncc @fitzgen
This issue or pull request has been labeled: "cranelift", "pulley"
Thus the following users have been cc'd because of the following labels:
To subscribe or unsubscribe from this label, edit the |
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Thanks for this!
pulley/src/interp.rs
Outdated
let b = self.state[operands.src2].get_u16x8(); | ||
for (a, b) in a.iter_mut().zip(&b) { | ||
// rounding average | ||
*a = (*a & *b) + ((*a ^ *b) >> 1) + ((*a ^ *b) & 1); |
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Could this perhaps be written as *a = (u32::from(a) + u32::from(b) + 1) / 2
? Basically the more classical version of an average which explicitly takes advantage of wider-precision arithmetic to avoid overflow issues.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
instantly convinced :))
Helps #9783