Initial support of Broadcom VideoCore IV #1147
Open
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 conditional jump is difficult to handle in the decompiler. A left shift followed by a (signed) right shift is easier.
When comparing to an immediate, a copy must be made. Currently, the value is copied twice: once in loophckcond to check the condition and once to display the value in the disassembly. However, the disassembly does not need the value itself; it can use a display stub and save one unnecessary P-Code.
Some functions in the firmware seem to guarantee that no registers are clobbered except r0. The caller then uses original r1-r5 values after the function call.
FLOAT_FLOOR does not produce a twos complement integer output, so: 1. ffloor and fceil do not need an int2float() 2. floor needs a trunc()
mumbel
referenced
this pull request
in nstarke/raspberrypi4-bootloader-analysis
Dec 6, 2021
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Outdated suggestions cannot be applied.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 VideoCore IV architecture documentation is not publicly available, but it has been reverse-engineered, see https://github.com/hermanhermitage/videocoreiv. This commit adds support for the reverse-engineered variant.