AEON: Add bt.lwst instruction #1321
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
The bt.lwst instruction uses almost the same encoding as bt.swst, except it has the LSB set. This means the immediate actually starts at bit 1, is 4 bits long, and is shifted left by 2 bits to calculate the offset. Note that both the bt.lwst and bt.swst mnemonics are guesses not based on any official documentation.
|
Until we know for sure what the mnemonic should be, |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The encoding for
bt.lwstis almost the same as that ofbt.swstexcept that it has the LSB set. This means the value for the immediate starts at bit 1, is 4 bits long, and is shifted left by 2 bits to calculate the offset. These instructions seem to be intended to provide more efficient stack access, using only 16 bits rather than the 24 bits ofbn.sw/bn.lwz.The
bt.lwstandbt.swstmnemonics are both entirely made up. I would love to know what the official mnemonics are or if these are actually just special cases of other load/store word instructions.