M1 Macs have an elaborate system of keys and certificates which allow the installation of second operating systems, as well as the primary OS, based on Ownership.
Apple silicon
Where code can make simple selections according to a conditional test, it may be possible to eliminate branching and ensure rapid execution.
The primary admin account on an M1 Mac is its Owner, responsible for authorising the installation and use of second operating systems. Here’s what can go wrong with Ownership.
An overview of bit operations, including MOVK for 16-bit immediate values, bit shift operations, bitwise AND, OR, XOR, and more, plus a cheat sheet.
Basic integer arithmetic – add, subtract, negate, multiply, multiply-and-add, and divide – in their many variations. With some catches for those more used to high-level languages.
Close to the top of my shortlist of new features in the next Apple Silicon Macs is that kernel panics become a thing of the past.
Explaining the LDR family of instructions for loading registers, MOV for moving one register to another, STR for storing to memory, and SXTx/UXTx for filling a register with smaller data types.
Management of kernel extensions has changed significantly in Big Sur and later. This overview for users contrasts kexts with user-level extensions which are replacing them.
How conditional branching can slow modern processors down badly, comparing assembly code with that generated by Apple’s Swift compiler, and some puzzles.
A strange volume named xART or xarts, secure memory management, and long random numbers: how they fit together to protect against replay attacks.
